Composites for Environmental Engineering 1119555299, 9781119555292

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Composites for Environmental Engineering

Scrivener Publishing 100 Cummings Center, Suite 541J Beverly, MA 01915-6106 Publishers at Scrivener Martin Scrivener ([email protected]) Phillip Carmical ([email protected])

Composites for Environmental Engineering

Edited by

Shakeel Ahmed and

Saif Ali Chaudhry

This edition first published 2019 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA and Scrivener Publishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA © 2019 Scrivener Publishing LLC For more information about Scrivener publications please visit www.scrivenerpublishing.com. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions. Wiley Global Headquarters 111 River Street, Hoboken, NJ 07030, USA For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com. Limit of Liability/Disclaimer of Warranty While the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials, or promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where appropriate. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read. Library of Congress Cataloging-in-Publication Data ISBN 978-1-119-55529-2 Cover image: Pixabay.Com Cover design: Russell Richardson Set in size of 12pt and Minion Pro by Manila Typesetting Company, Makati, Philippines Printed in the USA 10 9 8 7 6 5 4 3 2 1

This book is dedicated to Prof. Saiqa Ikram for her guidance and support throughout my career which has allowed me to obtain the level I am at. Dr. Shakeel Ahmed

Contents Preface

xvii

1 Composites: Types, Method of Preparation and Application as An Emerging Tool for Environmental Remediation 1 Bushra Fatima, Geetanjali Rathi, Rabia Ahmad and Saif Ali Chaudhry 1.1 Introduction 2 1.2 Classification Based on Matrix 4 1.2.1 Metal Matrix Composites (MMC) 5 1.2.2 Methods for Synthesizing Metal-Matrix Composites 5 1.2.3 Bonding in Metal Matrix Composites 9 1.2.4 Applications of Metal Matrix Composites 10 1.3 Polymer Matrix Composites 10 1.3.1 Classification of Polymer Matrix Composites 12 1.3.2 Methods for Synthesizing of Polymer Composites 13 1.3.3 Bonding in Polymer Matrix Composites 15 1.3.4 Applications of Polymer Matrix Composites 16 1.4 Ceramic Matrix Composites 16 1.4.1 Methods for Synthesizing Ceramic Matrix Composites 17 1.4.2 Advantage of Ceramic Matrix Composites 18 1.4.3 Disadvantages of Ceramic Matrix Composites 18 1.4.4 Applications of Ceramic Matrix Composites 18 1.5 Classification Based on Reinforcement 19 1.5.1 Fiber-Reinforced Composites 19 1.5.2 Particle Reinforced Composites 20 1.5.3 Structural Reinforced Composites 20

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Contents 1.6 Recent Advancement in Composites 1.6.1 Methods for Synthesizing Green Composites 1.6.2 Advantages and Disadvantages of Green Composites over Traditional Composites 1.6.3 Applications of Green Composites 1.7 Advantages of Composites 1.8 Disadvantages of Composites 1.9 Conclusion 1.10 Future Prospects 1.11 Acknowledgement References

21 22 22 22 23 23 24 24 25 25

2 Applications of Composites Materials for Environmental Aspects 33 Pintu Pandit, Kunal Singha, Akshay Jadhav, T.N. Gayatri and Utpal Dhara 2.1 Introduction 34 2.2 History of Composites for Eco-Friendly Engineering 35 2.3 Composites for Greenhouses 36 2.4 Polymers have been Reinforced by Fiber (FRP) for Greenhouse 36 2.4.1 Composites Employed in Controlling Humidity in the Home which is Green 36 2.4.2 Composite Films for Optical Transmission of Greenhouse 37 2.5 Composites Employed in Acoustic Applications 37 2.6 Natural Fiber Composites 40 2.6.1 Pretreatment of Natural Fiber 40 2.6.2 Factors Impacting on Bodily Functioning of Natural Fiber Composites 41 2.6.2.1 Fiber Selection 41 2.6.2.2 Matrix Selection 42 2.6.2.3 Interface Strength 42 2.6.2.4 Fiber Orientation 42 2.6.3 Jute-Coir Composites for Constructions 43 2.6.4 Bamboo Composites for Construction 43 2.7 Effective Factors for Low Frequency Acoustic Absorption 44

Contents 2.7.1 Fiber Size 2.7.2 Feed Size 2.7.3 Majority Density 2.7.4 Sample Layer Thickness 2.8 Composites Employed in Wind Energy 2.9 Composites Used in Wind Turbines 2.9.1 Impact of Wind Hit on the Composite Material 2.10 Composite Materials for the Marine Environment 2.11 Composite Materials for Aerospace Engineering 2.12 Composites Materials for Civil Engineering 2.13 Composite Materials Employed in Solar Energy Panels 2.14 Conclusions References 3 The Application of Mechano-Chemistry in Composite Preparation S. C. Onwubu, P. S. Mdluli, S. Singh, and M. U. Makgobole 3.1 Introduction 3.2 The Science of Mechanochemistry 3.3 Brief History of Mechanochemistry Application 3.4 Mechanochemical Tools 3.5 Applications of Mechanochemistry in the Milling of Eggshell Powder 3.6 Conclusions References 4 Fiber-Reinforced Composites for Environmental Engineering Gayatri T. Nadathur, Pintu Pandit and Kunal Singha 4.1 Introduction 4.2 Strength of FRC Materials 4.3 Composite Manufacturing 4.4 Environmental Sustainability of Composites 4.5 Green Composites 4.6 Composite Filtration Membranes/Media 4.7 Liquid (Water or Oil) Filtration Media 4.8 Air Filtration Media 4.9 Filtration/Separation of Oil-Water Liquid Mixtures 4.10 FRCs for Noise Reduction

ix 44 45 45 46 46 47 47 48 49 50 50 51 52 57 57 58 59 60 63 65 66 69 69 72 74 77 80 85 86 88 88 91

x

Contents 4.11 Fire Resistant FRCs 4.12 Conclusions References

5 Polymer Nanocomposites: Alternative to Reduce Environmental Impact of Non-Biodegradable Food Packaging Materials Shiji Mathew and Radhakrishnan EK 5.1 Introduction 5.2 Role of Food Packaging Materials 5.3 Environmental Impact of Food Packaging 5.4 Polymer Nanocomposites 5.5 Biopolymers as Packaging Materials 5.6 Advantages of Biopolymers 5.7 Reinforcements used in Bionanocomposites 5.7.1 Nanoclays-Layered Clays/Silicates 5.7.2 Metal and Metal Oxide Nanoparticles 5.8 Bionanocomposites 5.9 Polysaccharide-Based Bionanocomposites 5.9.1 Starch-Based Packaging Material 5.10 Protein-Based Bionanocomposites 5.10.1 Gelatin Bionanocomposites 5.11 Biodegradable Synthetic Polymers 5.11.1 Polylactic Acid-Based Packaging Materials 5.11.2 Poly (Vinyl) Alcohol-Based Packaging Materials 5.12 Properties of Bionanocomposites 5.12.1 Mechanical Properties 5.12.2 Barrier Properties 5.12.3 Thermal Properties 5.12.4 Biodegradability 5.13 Changes Occurring during Biodegradation Process 5.14 Methods of Preparation of Bionanocomposites 5.14.1 In Situ Polymerization 5.14.2 Melt Intercalation Technique 5.14.3 Solvent Casting 5.15 Bionanocomposite Characterization 5.16 Conclusions References

92 94 94

99 99 101 102 103 104 105 106 106 107 108 108 108 109 110 111 111 112 113 115 115 117 117 119 120 120 120 121 121 123 124

Contents 6 Environmental Science and Engineering Applications of Polymer and Nanocellulose-Based Nanocomposites Niranjan Thondavada, Rajasekhar Chokkareddy, Nuthalapati Venkatasubba Naidu and G. G. Redhi 6.1 Introduction 6.2 Preparation of Polymer Nanocomposites 6.2.1 Direct Compounding 6.2.2 In-Situ Synthesis 6.3 Environmental Applications of PNCs 6.3.1 Catalytic and Redox Degradation of Pollutants 6.4 Biocatalytic Nanocomposites 6.4.1 Adsorption of Pollutants 6.5 Preparation of Nanocellulose 6.5.1 Nanocellulose-Based Nanocomposites 6.5.2 Antimicrobial Filters 6.5.3 Catalysis 6.5.4 Energy Applications 6.6 Conclusion References 7 Nanocomposites of ZnO for Water Remediation Parita Basnet and Somenath Chatterjee 7.1 Introduction 7.2 Aqueous Pollutants 7.3 Types of ZnO NCs 7.3.1 M-ZnO NCs as Photocatalyst 7.3.1.1 Metal Doped/Incorporated-ZnO NCs as Photocatalyst 7.3.1.2 Metal Deposited-ZnO NCs as Photocatalyst 7.3.2 Semiconductor-ZnO (S-ZnO) NCs as Photocatalyst 7.3.3 Polymer-ZnO (P-ZnO) NCs as Photocatalyst 7.3.4 Mixed Metal, Semiconductor and/or Polymer-ZnO NCs as Photocatalyst 7.3.4.1 Bimetallic-ZnO NCs as Photocatalyst 7.3.4.2 Metal-Semiconductor-ZnO (M-S-ZnO) NCs as Photocatalyst

xi 135

136 137 137 138 141 141 142 151 155 158 162 162 164 166 166 179 180 182 184 185 185 188 191 193 197 197 199

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Contents 7.4 Other Applications Related to the Photocatalytic Activities of ZnO NCs 7.5 Conclusion 7.6 Acknowledgement References

8 Degradation of Organic Compounds by the Applications of Metal Nanocomposites Iffat Zareen Ahmad and Mohammed Kuddus 8.1 Introduction 8.2 Metal Oxides Used in Photocatalytic Degradation of Organic Pollutants in Wastewater 8.2.1 Titanium Dioxide 8.2.2 Graphene Oxide 8.2.3 Zinc Oxide 8.2.4 Cesium Oxide 8.2.5 Silver Salts 8.2.6 Bismuth Compounds 8.2.7 Copper Compounds 8.2.8 Gold Compounds 8.3 Conclusion References 9 Nanocomposites in Environmental Engineering Mohammad Nadeem Lone and Irshad A. Wani 9.1 Introduction 9.2 Polymeric Nanocomposites 9.2.1 PNC’s as Catalysts and Redox Active Media 9.2.2 PNC’s for Adsorption and Degradation of Pollutants 9.3 Magnetic Polymer Based Nanocomposites 9.3.1 Types of Magnetic Nanocomposites 9.3.1.1 Type I: Inorganic Core Shell Nanocomposites 9.3.1.2 Type II: Self Assembled Colloidal Nanocomposites 9.3.1.3 Type III: Organic–Inorganic Nanocomposites

201 206 222 222 235 237 244 244 248 249 250 250 251 252 254 255 256 263 264 265 265 285 287 287 287 288 288

Contents

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9.3.2 Synthesis of Magnetic Nanocomposites (MNC’s) 9.3.2.1 Ex-Situ Synthesis 9.3.2.2 In-Situ Synthesis 9.3.3 Environmental Applications 9.3.3.1 Elimination of Heavy Metals 9.3.3.2 Elimination of Toxic Dyes and Effluents 9.3.3.3 Removal of Oil from Water 9.4 Future Perspectives and Conclusion References

289 289 290 294 294 297 298 299 300

10 Bio-Composites from Food Wastes Pintu Choudhary, Priyanga Suriyamoorthy, J. A. Moses and C. Anandharamakrishnan 10.1 Introduction 10.2 Vegetables Waste 10.3 Fruit Waste 10.4 Coffee and Tea Waste 10.5 Animal-Based Food Waste 10.6 Food Grain Waste References

319

319 326 329 332 333 337 339

11 Properties of Food Packaging Biocomposites and Its Impact on Environment 347 K.S. Yoha, M. Maria Leena, J.A. Moses and C. Anandharamakrishnan 11.1 Introduction 348 11.2 Importance of Food Packaging 350 11.3 Packaging Materials Impact on Environment 351 11.4 Risks of Elemental Migration from Packaging Material 352 11.4.1 Contact Migration 354 11.4.2 Non-Contact Migration 355 11.5 Selection of Food Packaging Material 355 11.6 Biodegradable Polymers 356 11.6.1 Polysaccharides 358 11.6.1.1 Sugar-Based Biopolymers 358 11.6.1.2 Starch-Based Biopolymers 358 11.6.1.3 Cellulose-Based Biopolymers 359 11.6.1.4 Pectin 359

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Contents 11.6.2 Proteins 11.6.2.1 Collagen 11.6.2.2 Casein 11.6.2.3 Zein 11.6.2.4 Gluten 11.6.3 Seaweed Polymers 11.6.4 Plants Seed Mucilage 11.6.5 Micro-Organisms Synthesized Biopolymers 11.6.5.1 Polyhydroxyalkanoates (PHA) 11.6.5.2 Polyhydroxybutyrate (PHB) 11.6.5.3 Polyhydroxybutyrate-CoHydroxyvalerate (PHBV) 11.6.6 Bio-Derived Synthetic Polymers 11.6.6.1 Poly-Lactic Acid (PLA) 11.6.6.2 Poly Glycolic Acid (PGA) 11.6.6.3 Poly-Lactic-Co-Glycolic Acid (PLGA) 11.7 Bio-Based Polymeric Composite Materials 11.7.1 Starch-Based Composites 11.7.2 Poly(Hydroxyalkanoate)-Based Composites 11.8 Thermal and Mechanical Properties of Composites 11.9 Surface Modifications of Biocomposites 11.10 Conclusion References

12 Environmentally Benign Protocols for the Synthesis of Transition Metal Oxide: A Brief Outlook Neha D. Desai, Kishorkumar V. Khot, Tukaram D. Dongale, Atul Khot and Popatrao N. Bhosale 12.1 Introduction 12.2 Titanium Dioxide (TiO2) 12.2.1 Introduction 12.2.2 Method of Synthesis 12.2.3 Experimental of TiO2 Thin Film 12.2.4 Results and Discussions 12.3 Molybdenum Trioxide (MoO3) 12.3.1 Introduction 12.3.2 Experimental

360 360 361 361 362 362 366 367 367 367 368 368 368 369 370 370 370 371 371 372 373 374 383

384 385 385 387 389 389 392 392 394

Contents 12.3.3 Growth Mechanism 12.3.4 Structural Analysis 12.4 Zinc Oxide (ZnO) 12.4.1 Introduction 12.4.2 Experimental 12.4.3 TiO2 Memristor Devices 12.4.4 ZnO Memristor Devices References Index

xv 395 396 398 398 400 404 406 409 421

Preface Composites are materials made from two or more constituent materials with significantly different physical or chemical properties. The two materials combine together to give a new material with higher strength, toughness, stiffness, but also a higher resistance to creep, corrosion, wear or fatigue compared to conventional materials. It is composed primarily of a matrix i.e. a continuous phase which is armoured with secondary discontinues reinforcement phase. These materials have been used in a variety of products viz. spacecrafts, sporting goods, catalyst, sensors, actuators, biomedical materials, batteries, cars, furniture, aircraft components, etc. This book focusses on processing, properties of various types of composite materials, as well as their environmental engineering applications. This book examines the current state-of-art, new challenges, and opportunities of composites in environmental engineering. The chapters in this book covers nearly every conceivable topic related to composites in environmental engineering. Chapter 1 gives general account of composites, their types, properties and different methods of preparation. Chapter 2 deals with the utilization of Fiber reinforced polymer composite materials in environmental engineering with a focus on their green advantages. Chapter 3 provides a comprehensive overview on the advances made in the mechanochemical process of composite preparation. Chapter 4 gives detailed information about Fiber reinforced materials, their environmental sustainability and applications in environmental engineering. Chapter 5 discusses about the development, characterization, properties and food packaging applications of biodegradable polymer nanocomposites. xvii

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Preface

Chapter 6 provides a summary of the constructive techniques and current advances on the application of nanocomposites for treatment of pollutants, impurities sensing, and detection. Chapter 7 deals with Zinc Oxide nanocomposites and their application in water remediation. Chapter 8 provides an update on the different types of metal nanocomposites and their applications in degradation of organic dyes and to illustrate their efficiency in the area of pollution control. It also intends to provide an insight into the prospects and limitations of the metal nanocomposites for the degradation of organic pollutants. Chapter 9 present an overview of polymer and magnetic polymer nanocomposites, and their fabrication methods. It also discusses their recent applications like catalytic degradation, adsorption of pollutants, elimination of heavy metals, toxic dyes, effluents and removal of oil from water in environmental engineering. Chapter 10 is devoted to introduce different strategy to develop bio-composite from food wastes and its applications. Chapter 11 discusses about the properties of food packaging biocomposites materials and its impact on environment. Chapter 12 discusses environmental protocol for synthesis of transition metal oxides. We would like to express our sincere appreciations to the contributors of this book for their excellent contributions and ScrivenerWiley for their efforts involved in publication of this book. Shakeel Ahmed Saif Ali Chaudhry Summer 2019

1 Composites: Types, Method of Preparation and Application as An Emerging Tool for Environmental Remediation Bushra Fatima, Geetanjali Rathi, Rabia Ahmad* and Saif Ali Chaudhry† Environmental Chemistry Research Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi, India

Abstract Pollution is one of the major problems in most of the developing and developed countries. Water pollution remains a source of constant concern for environmentalists. With the growth of industrialization and globalization this issue is rising day by day. Several types of methods and materials have been used to avoid these problems, but often the methods proved to be useless in the absence of proper method and materials. In order to streamline these methods such as ion exchange, membrane filtration and adsorption, continuous new types of effort and materials are being made. In the material used so far, the best features of composite materials have come out, which has opened a new door in the field of treatment technologies. Composite is made up of different types of material having unique properties. The combination of different desired material is required to obtain the desired results in the composites thus resultant composites prove to be highly advance, unique and beneficial. In this chapter, we have discussed the different types of composite materials, and their preparation strategies and applications. The detail study on matrix and reinforced material based composites, and green composites have been conducted. This chapter will definitely be the preferred choice of environmentalists.

*Corresponding author: [email protected] † Corresponding author: [email protected] Shakeel Ahmed and Saif Ali Chaudhry (eds.) Composites for Environmental Engineering, (1–32) © 2019 Scrivener Publishing LLC

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Composites for Environmental Engineering

Keywords: Environment, pollution, composites, types of composites, matrix and reinforcement, green composites

1.1 Introduction Concerned with the problems of the environment, environmental engineers are developing the solutions by using the principles of biology and chemistry. Most common issues on which the engineers are focussed currently are disposal and recycling of the waste materials, air and water pollution, controlling the public health issues, removal of polluting substances from the surroundings, harmful effects caused by acid rain, global warming, auto mobile emissions, depletion of ozone layer etc. [1–3]. These effect the ecosystem which ultimately leads to human health problems and may sometimes even prove fatal. One such matter rising at the global level is water pollution [4–7]. Water which is a very precious resource is useful for us in a number of ways but its quality is degrading day by day. Major sources of water pollution include industrial, municipal, agricultural, natural, storm water, landfill, underground storage tank etc. [8–11]. Among them industrial waste plays a major role in polluting water bodies that release dyes and harmful metal ions [12, 13]. Human health is affected to a great extent and sometimes even proves fatal [14–16]. In the present times many types of materials or combination of material are being used for reducing the environmental pollution. Composites are one such type. Composites can be defined as “artificially made material made by the combination of two or more material that is different in the properties of its constituent”. Both the constituents are chemically different from each other and are separated by an interface [16–19]. Composites are different from that of conventional materials because of their superior properties [17–20]. Composites contain a continuous phase called Matrix and dispersed or discontinuous phase called Reinforcement or reinforcing material. Properties of the particles get changed when the size of the particles is below their critical size. As dimensions reach the nanometre level, the interactions at phase interfaces become largely improved, and this plays an important part in enhancing

Composites for Environmental Remediation 3 materials properties [21]. Matrix can be made from polymer (synthetic or natural), metal, ceramics and resins while the reinforcement are the nanoparticles, fibers, filled, whiskers, flakes, particulates, directionally solidified eutectics. Engineers and scientist are trying to make composites having better and better properties by combining different metals, alloys, ceramics, and reinforcement material. As a result of which composites are used for a wide range of applications. With the current advancements, composites are being replaced by the nanocomposites. A nanocomposite can be defined as a composite material formed by the combination of two or more components in which one component phase have nanoscale dimensions (0D,1D,2D) that is around 10–9 m. This nanometre sized materials are dispersed/embedded in the matrix of a polymer, metal or ceramic. It is a multiphase solid material. Nanocomposites are very much different from conventional composites for the exceptionally high surface to volume ratio of the reinforcing material and/or its exceptionally high accept ratio. Following parameters affect their properties like process used in the synthesis, material of the matrix which can exhibit nanoscale dimensions, loading, modification of the surface of nanoparticles, dispersion degree, size, shape and orientation of the nanoscale reinforcement phase and interaction between the matrix and the reinforcements. Due to the distinct properties of the constituents and inhomogeneous distribution of the reinforcement material these nanocomposites have direction dependent properties which we called anisotropy [22]. Interphase plays a very important role in the properties of the composites which tells us about the bonding between matrix and reinforcement material. Elasticity, strength, chemical potential varies from composites to composites since the preparation involves different types of reinforcement and matrices. But as the discontinuity in the above parameters occurs between the reinforcement and matrix, then not only by the medium of transition but also the matrix will create a chemical compound at interface due to the discontinuity in chemical potential [23]. Interfacial bonding is there between interface and matrix. This bonding will be strong and weak depending on the type of composites containing phases. Like in PMCs and MMCs strong bonding is chosen while in case of CMCs weak bonding will be chosen [24].

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Composites for Environmental Engineering

While synthesizing the composites/nanocomposites following points should be kept in mind: a) Matrix selection i. Amount of the polymeric matrix material. ii. Properties include aspect ratio, chemical nature, purity, distribution, orientation and geometry. iii. Interaction between the two i.e. adhesion [25]. b) Reinforcement selection i. The basic mechanical properties of the fiber itself. ii. The surface interaction of fiber and resin (the ‘interface’). iii. The amount of fiber in the composite (‘Fiber Volume Fraction’). iv. The orientation of the fibers in the composite [26].

1.2 Classification Based on Matrix Based on the type of matrix composites can be classified as (Figure 1.1):

Classification based on Matrix

Metal Matrix Composites

Polymer Matrix Composites

Figure 1.1 Classification based on matrix.

Ceramic Matrix Composites

Composites for Environmental Remediation 5

1.2.1 Metal Matrix Composites (MMC) Composites consisting of a matrix of a ductile metal (aluminium, magnesium, iron, cobalt, copper) or alloys which constitute the continuous phase in which nanoparticles are implanted as a reinforcement material called dispersed phase. These metals are of low density while the ceramic reinforcements like silicon carbide (SiC), aluminium oxide (Al2O3) or minerals like mica, graphite etc. The continuous phase results in change in the physical, chemical and mechanical properties of composites than those of matrix alone. Some common metal matrix nanocomposites include Ag/Au, Ni/PSZ [27], Ni/YSZ [28], Cu/Nb, Al/SiC [29]. While, they are much better than polymer composites in the properties like high strength, fracture toughness and stiffness, capability of tolerating high temperature conditions in the corrosive environment. The nanoparticles are having the following characteristics as a good reinforcement material: i. Non-reactiveness with matrix material. ii. Stability over a range of temperatures. iii. For high modulus matrix, high modulus NPs. The matrix of the composites itself alone are not having high strength and toughness but when nanoparticles are added they cause the difficulty in the dislocation movement which results in the better mechanical properties.

1.2.2 Methods for Synthesizing Metal-Matrix Composites Various methods for synthesizing metal matrix complex are (Figure 1.2): a) Spray pyrolysis The liquid matrix material gets atomize by an atomizer to produce a mist which is then passed to a substrate and a high velocity carrier gas loading the substrate material.

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Composites for Environmental Engineering Methods for Synthesizing Metal-Matrix Composites

Spray pyrolysis

Liquid metal infiltration

Vapor techniques

Chemical Vapor deposition

Rapid solidification

Physical Vapor Deposition

Stir casting

Colloidal methods

Chemical methods

Sol gel methods

Figure 1.2 Methods for synthesizing metal-matrix composites.

b) Liquid metal infiltration Infiltration means permeation of a liquid into something by filtration. Here the molten metal matrix after the thermal treatment infiltrated into a porous preform. Example: Silicon carbide (SiC) matrix composites  The molten silicon infiltered into the carbon (C) microporous preform by the capillary action when the molten temperature of silicon exceeds its melting point [30]. c) Vapor techniques i) Chemical Vapor Deposition A CVD apparatus has the following components gas delivery system, reactor chamber, energy source, substrate loading mechanism, vacuum system, exhaust system, process control equipment, and exhaust treatment system. This method involves the deposition of the material in gaseous form (which will get at their ambient temperature) onto a substrate after passing through a reaction chamber. The substrate is heated previously. After it comes in contact with previously heated substrate a chemical reaction will take place and material is deposited on or near the solid surface. This method is versatile in nature, it can be used for the fabrication of

Composites for Environmental Remediation 7 different metallic or ceramic composites. Also, a highly purified product will be achieved since the impurities are removed by distillation techniques from the gaseous reactants. ii) Physical Vapor Deposition Most common PVD process (Figure 1.3) are sputtering and evaporation. Sputtering is a plasma assisted technique in which a source target after bombardment through the accelerated gaseous ions creating the vapors. The evaporation involves the production of vapors by heating the material in vacuum. PVD involves the condensation then evaporation and finally go back to condensation phase of a material. After the consolidation of the nanocomposites, supersaturation of the vapor phase occurs in an inert atmosphere so as to promote the metal nanoparticles condensation. This method is used to deposit thin layers of material in nm range.

Solid target material

Flux of ejected targeted atoms

Thin film deposition on substance Substrate

External energy supply to substrate (heating)

Figure 1.3 Apparatus of physical vapor deposition.

Target excitation

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Composites for Environmental Engineering d) Rapid solidification Rapid solidification means rapid liquid state quenching. Products obtained by this process are powder, flakes, ribbons, wires and foils. Here the molten metal infiltrated a preform of fibers or particles until both are completely melt. This molten alloy is then freezing in the inter spaces of the fiber and form the composites. Example: Cast iron and aluminium silicon alloys [31]. e) Stir casting It is one of the simplest methods. The metal matrix gets a molten form by heating it into a furnace, then reinforcement material is dispersed into the molten matrix which is followed by mechanical stirring. So that the mixture will be completely mixed and we get a suitable dispersion. Finally, the dispersion gets solidified in appropriate conditions. f) Chemical methods [32] i) Colloidal Methods ii) Sol Gel Methods It involves the two basic components for preparing composites. First a sol and then gel. Whole process involves the hydrolysis and condensation of the matrix and reinforcement dispersion mixture. After chemical reactions the sol gets converted into a gel. Further process involves the heating treatment in the gel gets converted into oxides as final material which results in the formation of composites. A large difference in structural properties is achieved according to the change of temperature. Example: Fe/Au-containing nanocomposite [33].

Composites for Environmental Remediation 9

1.2.3 Bonding in Metal Matrix Composites In MMC interface i.e. bonding between metal matrix (primary phase) and reinforcement (secondary phase) is one of the following (Figure 1.4a–c):

Primary (Matrix) Phase Secondary (reinforcing) Phase Interface

Figure 1.4a Direct bonding between primary and secondary phase.

Primary (Matrix) Phase Secondary (reinforcing) Phase, fiber Interface (Third ingredient)

Figure 1.4b Addition of third material to bond the primary phases.

Primary (Matrix) Phase Secondary (reinforcing) Phase Interface (solution of primary and secondary phases)

Figure 1.4c Formation of inter phase by solution of primary and secondary at inter phases at their boundary.

10 Composites for Environmental Engineering Types of Interfacial bonding at interface: i.

Mechanical bonding depends on the roughness degree of the fiber. ii. Chemical bonding occurs between the chemical groups of the matrix and reinforcement and their compatibility. iii. Electrostatic bonding involve interaction between oppositely charged surface of matrix and reinforcement. iv. Reaction or inter-diffusion bonding.

1.2.4 Applications of Metal Matrix Composites i.

Pushrod i.e. used in automobile application is made from aluminium metal matrix composite. It is highly used as this composite is having attractive physical, mechanical and elastic properties [34]. ii. Reinforced MMC are light in weight so they are used as a component of aircraft and helicopters. iii. Al/SiC/fly ash composites used for designing of various components in automotive sector because of great tensile strength and hardness as compared to unreinforced aluminium [35]. iv. Al/SiC/B4C composites are preferred for heavy duty vehicles and high wear resistance applications. While comparing to single ceramic reinforced composites these possessing greater hardness and toughness it is found [35]. v. Carbon-carbon composites which are used in braking system, refractory material etc.

1.3 Polymer Matrix Composites Composites consist of a matrix of polymer such as homopolymer, copolymer, block copolymer, unsaturated polyester, epoxy, polycarbonate, polyvinylchloride, nylon, polystyrenes or polymer blends being dispersed with fibers, whiskers, platelets or particles, glass, carbon,

Composites for Environmental Remediation 11 steel, one-dimensional (nanotubes and fibers), two-dimensional (layered materials like clay) or three-dimensional (spherical particles). So, the continuous phase comprises the matrix while the discontinuous phase is reinforcement. In the application in which the polymer nanocomposites are employed the choice depends on the type of reinforcement. The properties of nanocomposites are entirely affected by the nanoparticles which are used. This is called as nano-effect [36]. Nanoparticles surface area, surface energy and type of geometry effect the matrix completely in terms of strength. Over all the properties of the composites depend on these nanosized reinforcements. Bond between matrix and the reinforcement are weak intermolecular force but chemical bond also exists if the reinforcement is dispersed at an atomic or molecular level. The matrices possess the following physical and chemical properties: i.

High elastic stiffness and strength with a small concentration of nano additives ii. Barrier resistance iii. Wear resistance iv. Flame retardancy v. Clay minerals (montmorillonite, saponite, hectorite etc) added as filler materials in polymer matrix for obtaining high strength and hardness. vi. Magnetic, electrical and optical properties. vii. Enhanced thermal stability viii. Polymer resins as reinforcement produces a dramatic improvement in their biodegradability. ix. Hydrophobicity to hydrophilicity x. Insulators to semiconductors to conductors One of the most striking features of the polymer matrix is that they are highly porous and nanoparticles due to their high surface area resulting into the larger area of matrix is in nanoparticles region. As a result, gradual transition occurs in physical and chemical properties. In order to form a better and useful composites two criteria should be kept in mind. Firstly, the polymer matrix and reinforcement interaction must be very efficient. Secondly in the matrix,

12 Composites for Environmental Engineering dispersion of nanoparticles should be very effective so the processing is decided [37].

1.3.1 Classification of Polymer Matrix Composites i.

Thermoplastic Matrix Polymer Composites They comprise a matrix of thermoplastic polymers (polyethylene, polystyrene, polyamides, nylon polypropylene) in which reinforcement are dispersed. Thermoplastic polymers are linear or branched polymers or 2D structures in which chains of molecules are not interconnected to one another. The individual molecules have linear structure with no chemical linkage between them. They are held together by weak secondary bond (intermolecular force such as Vander Waal and hydrogen forces). These polymers can change their shape and melt on heating and become hard on cooling. So, recycling can be done without affecting the properties. The processing methods used for such polymers are injection moulding, film stacking, diaphragm forming and thermoplastic tape lying. ii. Thermosets Matrix Polymer Composites They comprise a matrix of thermoset polymers (epoxy, polyesters, phenolic polyamide resins) in which different types of fillers are dispersed (Carbon Nanofibers (CNFs), Montmorillonite organoclays (MMT), Metallic nanoparticles, Carbon nanotubes (CNTs), ceramics). These polymers are heavenly cross-linked, having a 3D structure. They do not melt and cannot be remoulded but will decompose on heating. One of the forms of chopped fiber composites offer a wide range of applications. These are better as compared to thermoplastic in rigidity and improved mechanical properties. Processing methods includes hand layup, spray layup techniques, filament winding, pultrusion, resin transfer moulding and autoclave moulding.

Composites for Environmental Remediation 13

1.3.2 Methods for Synthesizing of Polymer Composites Various methods for synthesizing of polymer composites are listed below (Figure 1.5): i)

Intercalation of the Polymer/Pre-Polymer from Solution Plate like nanofillers are dispersed in the polymer matrix. This method is suitable for layered silicates composites. Silicates reinforcement is penetrating into the matrix, depending upon the degree of penetration composites structure ranging from intercalated to exfoliated types. Polymer is dissolved in co-solvent while plate like nanofillers in solvent. Both the solutions are mixed together and polymer chains displaced the nano-platelet solvent and will intercalate in it. Thus, leading to the formation of polymer layered silicate composites.

Intercalation of the polymer In-situ intercalative polymerization

Sol-gel process

In-situ polymerization

Methods for Synthesizing of Polymer composites

Template synthesis

Melt intercalation

Direct mixture of polymer and particulates

Figure 1.5 Methods for synthesizing of polymer composites.

14 Composites for Environmental Engineering Examples: Clay with PCL, PLA, HDPE, PEO, PVA, PVP, PVA, etc. [38,39, 40–46]. ii) In-Situ Intercalative Polymerization In this method the nanofillers that are used as a reinforcement being dispersed in the monomer solution and the fillers get swollen. Polymerization of the resulting solution is done by heat, radiation or by organic initiator. Examples includes montmorillonite with N6/PCL/ PMMA/PU/Epoxy [47–51]. iii) Melt Intercalation Softening temperature of polymer is the key parameter here. In this method both the nanofillers (clays) and the polymer matrix are mixed together above softening temperature of the polymer. Annealing of the solution mixture is done either statistically or under shear. Due to which the monomers are being dispersed into the layers of the host material. Examples: Montmorillonite with PS/PEO/PP/PVP, Clay-PVPH [52–56]. iv) Direct Mixture of Polymer and Particulates One of the simplest and `easiest method of synthesizing polymer matrix composite involves the direct mixing of the polymer and fiber when the polymer melts above its glass transition temperature this method is called melt compounding method. Second method involves the mixing of both polymer and fiber in a solvent which is called solvent method [57]. v) Template Synthesis Used for the synthesis of LDH nanocomposites. This method involves the dissolving of both polymer matrix and clay layers in an aqueous solvent. Nucleation and growth of clay layers takes place when the polymers get trapped inside the layers at high temperature. This polymer is water soluble, acts as a source of template [58–62]. Examples: Hectorite with PVPR, HPMC, PAN, PDDA, PANI.

Composites for Environmental Remediation 15 vi) In-Situ Polymerization In this method reinforcement is dispersed in the polymer matrix (which is the monomer having low molecular weight, a precursor) solution, when the mixture of reinforcement and polymer matrix gets homogenised, an appropriate catalyst is added for the polymerization process. Examples: PET/CaCO3, Epoxy vinyl ester/ Fe3O4; Epoxy vinyl ester/γ-Fe2O3; Poly (acrylic acid) (PAA)/ Ag, PAA/Ni and PAA/Cu AgNO3, NiSO4 and CuSO4 [63–66]. vii) Sol-Gel Process This method is also known as chemical solution deposition. By using this method for synthesizing metal oxide nanocomposites, the texture and surface properties can be easily controlled. It involves three steps: • Hydrolysis: It involves the production of hydroxide solution of reinforcement and monomer which is called “sol”. • Condensation: It involves the formation of a 3D interconnected network formed by the polymerization reaction and the hydrolysis. • Drying: This process involves drying of gel and formed composites [67]. Examples: 2-hydroxyethyl acrylate (HEA)/SiO2, Polyimide/SiO2; polyimide/silica, polyethylacrylate/ SiO2, PMMA/SiO2, polycarbonate/SiO2 and poly (amide-imide)/TiO2 [68–71].

1.3.3 Bonding in Polymer Matrix Composites Thermosetting polymers have epoxy, polyesters, phenolic polyamide resins which are polar in nature and have surface energy values which provide good wetting to the reinforcement via the intrinsic adhesive adsorption mechanism. The inter-atomic and intermolecular forces like dispersion forces, primary chemical (e.g. covalent bonding)

16 Composites for Environmental Engineering forces, dipole forces and hydrogen bond forces are acting in between the adhesive/composite’s interphase. While in case of thermoplastic polymers (polyethylene, polystyrene, polyamides, nylon polypropylene) surface free energy have lower values, therefore bonding in these are quite difficult. So engineers are using special adhesive materials after the pre-treatment of the composites materials.

1.3.4 Applications of Polymer Matrix Composites i.

In Aerospace industry, carbon fibers are extensively used as reinforcement materials. ii. As polymers are less dense consisting of light carbon and hydrogen atoms they are used as structural components and in applications which have the need of lightweight materials such as automobile, defence, aerospace and electronics.

1.4 Ceramic Matrix Composites Ceramic a word derived from a Greek word “keramikos” meaning pottery. Ceramics are the inorganic and non-metallic solid material exhibiting strong ionic and to some extent covalent bonding, having crystalline nature. They can tolerate high temperature conditions but on mechanical and thermal loading catastrophic failure occurs. So, lack of toughness is one of the main reasons that these are not used in structural applications. So, ceramic matrix composites have been synthesized now a day for improving the toughness. They are best considered for high temperature conditions [72]. Ceramic matrix composites are the composites consisting of ceramic matrix reinforced with different kinds of reinforcement, thus forming a ceramic fiber reinforced ceramic material. Their main applications are restricted due to their brittle behavior. Due to the fact that ceramic materials have superior properties they are used both as matrix material and reinforcement in many industrial applications. Main function of reinforcement is not only to provide the toughness by blocking the dislocation movement and act as a barrier for crack propagation but also improved properties such as electrical

Composites for Environmental Remediation 17 and thermal conductivity, thermal expansion, hardness, thermal shock resistance, high corrosion resistance. For improving the strength, particle strengthening and fiberreinforcement have been utilized. Reinforcement of ceramic matrix is done by either continuous long fiber or discontinuous short fibers. One of the main disadvantages of reinforcing ceramic matrix with short fibers is catastrophic as compared to long discontinuous fiber. Examples of short fiber composites: aluminium nitride (AIN), titanium boride (TiB2), oxide (alumina) or nonoxide (silicon carbide) ceramic matrix reinforced by the whiskers of silicon carbide (SiC), zirconium oxide (ZrO2). Example of long discontinuous fiber: Silicon carbide matrix composites, mullite (alumina and alumina -silica (mullite) matrix composites, carbon-carbon composites [73].

1.4.1 Methods for Synthesizing Ceramic Matrix Composites Various methods for synthesizing Ceramic Matrix Composites given in Figure 1.6:

Chemical vapor infiltration Solid state route

Coprecipitation route

Liquid phase infiltration

Methods for synthesizing of Ceramic Matrix Composites

Melt synthesis Laser synthesis

Sol-gel method

Direct metal oxidation or chemical bonding

Figure 1.6 Methods for synthesizing of ceramic matrix composites.

18 Composites for Environmental Engineering

1.4.2 Advantage of Ceramic Matrix Composites i. ii. iii. iv. v. vi.

Non-catastrophic failure Higher chemical stability Corrosion resistance Wear resistance Do not react with chemicals It can withstand high temperature [73]

1.4.3 Disadvantages of Ceramic Matrix Composites i.

CMC requires high temperature for processing that can be employed for temperature reinforcement. ii. High temperature is required during processing process which results in complex manufacturing thus resulting in complexity and expensive materials.

1.4.4 Applications of Ceramic Matrix Composites i.

Silicon carbide whisker-reinforced Al2O3 and Si3N4 are used in cutting tool. ii. Ceramic matrix composites used as industrial materials such as high alloy steels and refractory metals. iii. Discontinuous reinforced ceramics are being used in chute liners. iv. Silicon carbide whisker-reinforced Al2O3 and Si3N4 used in Cutting tools. v. Aerospace vi. Jet engine vii. Components for burners, flame holders. viii. Components for high temperature gas turbines such as turbine blade, combustion chambers. ix. Hot fluid channel x. In Energy sector silicon carbide continuous fiber reinforced matrix composites for nuclear applications are used due to high temperature strength xi. Industrial uses of CMCs include furnace materials, energy conversion systems, gas turbines and heat engines.

Composites for Environmental Remediation 19

1.5 Classification Based on Reinforcement Based on reinforcement composites can be classified as (Figure 1.7):

1.5.1 Fiber-Reinforced Composites Composites having the dispersed phase is in the form of fibers are classified as whiskers, fibers and wires on the basis of diameter. Fibers are of glass fibers, silicon carbide fibers, high silica and quartz fibers, alumina fibers, metal fibers and wires, graphite fibers, boron fibers, aramid fibers and multiphase fibers are used. Glass fibers, is again classified into E-glass, A-glass, R-glass etc. [74]. They are further classified as: • Continuous (aligned) • Discontinuous (short)-Aligned and randomly oriented The characteristic properties of fiber-reinforced composites depend on fiber length (long and short), fiber orientations (continuous and aligned, discontinuous and aligned, and discontinuous and randomly oriented fiber reinforced composites) fiber shape, composition, concentration, fiber phase and matrix phase. These parameters effect the specific strength i.e. ratios of tensile strength to specific gravity and specific modulus i.e. ratio of modulus of elasticity to specific gravity. Matrix phase of fiber reinforced composites are made from ceramic, polymer or metal which are discussed above.

Classification based on Reinforcement

Fiberreinforced composites

Continuous (aligned)

Discontinuous (short)

Particulates Composites

Large-particle

Dispersionstrengthened composites

Figure 1.7 Classification based on reinforcement.

Structural Composites

Sandwich composites

Laminated composites

20 Composites for Environmental Engineering

1.5.2 Particle Reinforced Composites For a composite to be good in stiffness and strength there must be good interaction and bonding in between the composites constituting material i.e. matrix and reinforcement. An interaction at atomic level is one of the reasons of high strength. Dispersion strengthened composites include the extremely small particles that are dispersed to a great extent and well bonded in matrix material thus, provide great strength. They are further classified as: • Large-particle • Dispersion-strengthened composites Large particle composites contain larger size particles that are not well dispersed like smaller ones. Reinforcement action causes the enhancement in mechanical properties.

1.5.3 Structural Reinforced Composites They are further classified as: • Laminated composites Wood considered as the best example for describing laminated composites. Laminated composites are 2D-dimensional sheets of material containing a layer of materials bonded together. Stacking and cementing of the layers in a particular direction, length of the layer that are bonded with each other tells the degree of strength. Laminated structure of the modern times having complex laminated structure, metal-plastic laminates (metal-plastic, vinyl-metal laminates) are the examples. Processing methods include adhesive bonding, pre-coating or cladding methods. • Clad or Sandwich composites Two separate sheets bonded by an adhesive thicker core. Source of stiffness and strength in the composite are the sheets parts which are made up of aluminium alloys, titanium, steel and fiber reinforced plastics. Thickness of the sheets kept in such a way that it

Composites for Environmental Remediation 21 can withstand the stresses that are resulting from the loading. Core present in between the sheets serves many functions: i) Act as source of support in between the sheets ii) Providing stress and stiffness iii) Capable of withstanding transverse stress. These composites are used in a number of ways like roofs, wall of building floors.

1.6 Recent Advancement in Composites Green composites are gaining attention at global scale because of environmental awareness, reductions in usage of oil-based resource, consumption of renewable and biodegradable resources during processing. They are not only being used in engineering applications but are also gaining importance at economical scale. Green composites are composites of natural resins/polymers. The biodegradable material constitutes the continuous phase embedded with plant fibers as reinforcement or discontinuous phase. These plant fibers act as a source of mechanical strength. Most commonly used polymers for green composites are polylactic acid, polyhydroxybutyrate, starch etc. Examples: Kevlar/SPC based resin, Cellulose/ SPC based resin. Natural fibers may be classified into two broad categories: • Non-wood fibers: They are of following types -bast fibers, leaf fibers, seed fibers, fruit fibers and stalk fibers. • Wood fibers: They are of following types: i) Hardwood fibers-fibers from aspen and birch ii) Soft wood fibers-fibers from pines, spruces, larches Biodegradable polymers can be classified on the basis of their origin: i. Natural ii. Synthetic

22 Composites for Environmental Engineering Methods for synthesizing green composites

Open mould process

Hand layup

Spray layup

Tape layup

Closed mould process

Filament winding

Transfer moulding

Injection moulding

Compression moulding

Figure 1.8 Methods for synthesizing green composites.

1.6.1 Methods for Synthesizing Green Composites Some of the important methods for synthesizing green composites are listed in (Figure 1.8).

1.6.2 Advantages and Disadvantages of Green Composites over Traditional Composites Despite green composites been proven having advantages over traditional composites, they do have certain drawbacks that need to be worked upon.

1.6.3 Applications of Green Composites i.

Used in aircrafts and ships because of the light weight ii. In mobile phone for example composites of kenaf and PLA for reducing CO2 emissions. iii. Banana fibers and its composites used as interior decoration material iv. Composites of plant derived fiber and crop-derived plastic use for solution of uncertainty of petroleum supply v. In spare tire cover, circuit boards PLA/kenaf fiber composites are used.

Composites for Environmental Remediation 23

1.7 Advantages of Composites i.

Wide variety of methods, different types of reinforcement and matrix material offers the use of composites in wide range of applications. ii. Composites offer excellent resistance to corrosion, chemical attacks, impact damage and heat. iii. Composites are able to withstand high temperature for carbon-carbon composite used for designing leading edges of the wings in space shuttle can retain its properties even at 2000°C. iv. Properties are greatly improved that include high strength or stiffness to weight ratio, improved torsional stiffness, dimensional stability, improved weatherability, improved friction and wear properties, heat sink properties, improved dent resistance, improved reliability for fewer structural failures. v. Cost of production is low.

1.8 Disadvantages of Composites Although possessing many advantages composite materials have some of the draw backs such as (Figure 1.9): i.

Fabrication and material cost is high for example composites synthesized from biodegradable components are too expensive. ii. Composite materials are difficult to repair, more brittle and easily damaged. iii. Isotropic a word used in metals while for nonmetals anisotropic. In composites anisotropy exists, which means that the properties are not same in all directions while metals possess isotropy. So, the mechanical characterization is a complex matter and requires more parameters as compared to metals.

24 Composites for Environmental Engineering Advantage over traditional composites Less expensive Reduced weight Increased flexibility

Disadvantage over traditional composites Moisture absorber

Less compatible with conventional resin systems

Lower strength

Renewable resource Eco friendly processing No skin damage

Figure 1.9 Advantages and disadvantages of green composites over traditional composites.

iv. Matrices are generally weak, corroded and also degraded in the environment. v. While comparing with metals, composite has less service experience and durability.

1.9 Conclusion It may be concluded that composites are a promising material for treatment of water. Wide variety of composite material provide for treatment of various types of impurities present in water.

1.10 Future Prospects In the field of water treatment the green composite material are having a bright future. They are eco friendly and thus are a choice

Composites for Environmental Remediation 25 for environmentalists. Further modifications will provide better results.

1.11 Acknowledgement The Financial support from the University Grant Commission, UGC, India and Department of Chemistry, Jamia Millia Islamia, New Delhi, India, is gratefully acknowledged.

References 1. Tara, N., Siddiqui, S.I., Rathi, G. et al., Nano-engineered Adsorbent for the removal of dyes from water: A review. Curr. Anal. Chem., 15, 1, 2019. 2. Siddiqui, S.I., Rathi, G., Chaudhry, S.A., Acid washed black cumin seed powder preparation for adsorption of methylene blue dye from aqueous solution: Thermodynamic, kinetic and isotherm studies. J. Mol. Liq., 264, 275–284, 2018. 3. Siddiqui, S.I., Rathi, G., Chaudhry, S.A., Qualitative analysis of acid washed black cumin seeds for decolorization of water through removal of highly intense dye methylene blue. Data Brief, 20, 1044–1047, 2018. 4. Siddiqui, S.I., Ravi, R., Chaudhry, S.A., Removal of arsenic from water using graphene oxide nano-hybrids. In: A new generation material graphene: Applications in water technology. M. Naushad (ed.), Springer, Cham, 2019. https://doi.org/10.1007/978-3-319-75484-0_9. 5. Siddiqui, S.I. and Chaudhry, S.A., Removal of arsenic from water through adsorption onto metal oxide-coated material. Mater. Res. Found., 15, 227–276, 2017. 6. Siddiqui, S.I. and Chaudhry, S.A., A review on graphene oxide and its composites preparation and their use for the removal of As3+ and As5+ from water under the effect of various parameters: Application of isotherm, kinetic and thermodynamics. Process Saf. Environ. Protect., 119, 138–163, 2018. 7. Chaudhry, S.A., Ahmed, M., Siddiqui, S.I., Ahmed, S., Fe(III)-Sn(IV) mixed binary oxide-coated sand preparation and its use for the removal of As(III) and As(V) from water: Application of isotherm, kinetic and thermodynamics. J. Mol. Liq., 224, 431–441, 2016. 8. Chaudhry, S.A., Zaidi, Z., Siddiqui, S.I., Isotherm, kinetic and thermodynamics of arsenic adsorption onto iron-zirconium binary

26 Composites for Environmental Engineering

9.

10.

11.

12.

13.

14.

15.

16. 17.

18.

oxide-coated sand (IZBOCS): Modelling and process optimization. J. Mol. Liq., 229, 230–240, 2017. Siddiqui, S.I. and Chaudhry, S.A., Nigella sativa plant based nanocomposite-MnFe2O4/BC: An antibacterial material for water purification. J. Clean. Prod., 200, 996–1008, 2018. Siddiqui, S.I., Chaudhry, S.A., Islam, S.U., Green adsorbents from plant sources for the removal of arsenic: An emerging wastewater treatment technology. In: Plant-based natural products: Derivatives and applications. S.U. Islam (ed.), John Wiley & Sons, Inc., Hoboken, NJ, USA, 193–211, 2017. https://doi.org/10.1002/9781119423898. ch10. Siddiqui, S.I. and Chaudhry, S.A., Nanohybrid composite Fe2O3ZrO2/BC for inhibiting the growth of bacteria and adsorptive removal of arsenic and dyes from water. J. Clean. Prod., 223, 849–868, 2019. Siddiqui, S.I., Ravi, R., Rathi, G. et al., Decolorization of textile wastewater using composite materials. In: Nanomaterials in the wet processing of textiles. S.U. Islam and B.S. Butola (eds.), John Wiley & Sons, Inc., pp. 187–218, 2018. Siddiqui, S.I., Manzoor, O., Mohsin, M. and Chaudhry, S.A., Nigella sativa seed based nanocomposite-MnO2/BC: An antibacterial material for photocatalytic degradation, and adsorptive removal of Methylene blue from water. Environ. Res., 171, 328–340, 2019. Siddiqui, S.I., Fatima, B., Tara, N. et al., 15: Recent advances in remediation of synthetic dyes from wastewaters using sustainable and lowcost adsorbents. In: The textile institute book series, The impact and prospects of green chemistry for textile technology, S.U. Islam and B.S. Butola (eds.), Woodhead Publishing, 2019. https://doi.org/10.1016/ B978-0-08-102491-1.00015-0. Siddiqui, S.I. and Chaudhry, S.A., Arsenic: Toxic effects and remediation. In: Advanced materials for wastewater treatment, S.U. Islam (ed.), John Wiley & Sons, Inc., pp. 1–27, 2017. https://doi. org/10.1002/9781119407805.ch1. Siddiqui, S.I. and Chaudhry, S.A., Removal of arsenic from water using nanocomposites, A Review. Curr. Environ. Eng., 4, 81–102, 2017. Siddiqui, S.I. and Chaudhry, S.A., Iron oxide and its modified forms as an adsorbent for arsenic removal: A comprehensive recent advancement. Process Saf. Environ. Prot., 111, 592–626, 2017. Abbasi, H., Antunes, M. and Ignacio, J., Velasco Recent advances in carbon-based polymer nanocomposites for electromagnetic interference shielding. Prog. Mater. Sci., 103, 319–373, 2019.

Composites for Environmental Remediation 27 19. Siddiqui, S.I. and Chaudhry, S.A., Organic/inorganic and sulfated zirconia nanocomposite membranes for proton-exchange membrane fuel cells. In: Organic-inorganic composite polymer electrolyte membranes, D. Inamuddin, A. Mohammad, and A. Asiri (eds.), Springer, Cham, 2017. https://doi.org/10.1007/978-3-319-52739-0_9. 20. Siddiqui, S.I., Naushad, M., Chaudhry, S.A., Promising prospects of nanomaterials for arsenic water remediation: A comprehensive review. Process Saf. Environ. Protect., 126, 60–97, 2019. 21. Camargo, F.H.C., Satyanarayana, K.G., Wypych, F., Nanocomposites: Synthesis, structure, properties and new application opportunities. Mater. Res., 12, 1, 1–39, 2009. 22. Paliwal, B. and Cherkaoui, M., Estimation of anisotropic elastic properties of nanocomposites using atomistic-continuum interphase model. Int. J. Solids Struct., 49, 18, 2424–2438, 2012. 23. Jesson, D.A. and Watts, J.F., The Interface and Interphase in Polymer Matrix Composites: Effect on Mechanical Properties and Methods for Identification. Polym. Rev., 52, 3, 321–354, 2012. 24. Seshan, S., Guruprasad, A., Prabha, M., Sudhakar, A., Fiber-reinforced metal matrix composites - a review. J. Indian Inst. Sci., 76, 1–14, 1995. 25. Chen, W., Zhang, J., Cai, W., Sonochemical preparation of Au, Ag, Pd/SiO2 mesoporous nanocomposites. Scr. Mater., 48, 2, 1061–1066, 2003. 26. Herrera-Franco, P.J. and Valadez-Gonzalez, A., Mechanical properties of continuous natural fiber-reinforced polymer composites. Comput. Part A: Appl. Sci. Manuf., 35, 3, 339–345, 2004. 27. Aruna, S.T. and Rajam, K.S., Synthesis, characterisation and properties of Ni/PSZ and Ni/YSZ nanocomposites. Scr. Mater., 48, 5, 507– 512, 2003. 28. Xiaochun, L., Yang, Y., Cheng, X., Ultrasonic-assisted fabrication of 123 metal matrix nanocomposites. J. Mater. Sci., 39, 9, 3211–3212, 2004. 29. Marchal, Y., Delannay, F., Froyen, L., The essential work of fracture as a means for characterizing the influence of particle size and volume fraction on the fracture toughness of plates of Al/SiC composites. Scr. Mater., 35, 2, 193–198, 1996. 30. Hayun, S., Rittel, D., Frage, N., Dariel, M.P., Static and Dynamic Mechanical Properties of Infiltrated B4C-Si Composites. Mater. Sci. Eng., 487, 1, 405–409, 2008. 31. Macke, A., Schultz, B.F., Rohatgi, P.K., Gupta, N., Metal Matrix Composites for Automotive Applications, in: Advanced Composite

28 Composites for Environmental Engineering

32.

33. 34.

35.

36. 37.

38.

39.

40.

41. 42. 43. 44. 45.

46.

Materials for Automotive Applications: Structural Integrity and Crashworthiness, pp. 313–344, 2013. Henrique, P., Camargo, C., Satyanarayana, K.G., Wypych, F., Nanocomposites: synthesis, structure, properties and new application opportunities. Mater. Res., 12, 1, 1–39, 2009. Carpenter, E.E., Kumbhar, A. et al., Synthesis and magnetic properties of gold–iron– gold nanocomposites. Mater. Sci. Eng., 286, 1, 81–86, 2000. Murugan, S.S. and Jegan, V., Development of Hybrid Composite for Automobile Application and its Structural Stability Analysis Using ANSYS. IJMSME, 3, 1, 23–34, 2017. Singh, J. and Chauhan, A., Characterization of hybrid aluminium matrix composites for advanced applications-A Review. J. Mater. Res. Technol., 5, 2, 159–169, 2016. Paul, D.R. and Robeson, L.M., Polymer nanotechnology: Nanocomposites. Polymer, 49, 15, 3187–3204, 2008. Ciprari, D., Jacob, K., Tannenbaum, R., Characterization of Polymer Nanocomposite Interphase and Its Impact on Mechanical Properties. Macromolecules, 39, 16, 6565–6573, 2006. Ounaies, Z. and Park, C., Electrical properties of single wall carbon nanotube reinforced polyimide composites. Compos. Sci. Technol., 63, 11, 1637–1646, 2003. Jimenez, G., Ogata, N., Kawai, H., Ogihara, T., Structure and thermal/ mechanical properties of poly ( -caprolactone)-clay blend. J. App. Polym. Sci., 64, 11, 2211–2220, 1998. Ogata, N., Jimenez, G., Kawai, H., Ogihara, T., Structure and thermal/ mechanical properties of poly (l-lactide) – clay blend. J. Polym. Sci., Part B: Polym. Phys., 35, 2, 389–396, 1997. Jeon, H.G., Jung, H.T., Lee, S.W., Hudson, S.D., Morphology of polymer silicate nanocomposites. Polym. Bull., 41, 1, 107–113, 1998. Aranda, P. and Ruiz-Hitzky, E., Poly (ethylene oxide) - silicate intercalation materials. Chem. Mater., 4, 6, 1395–1403, 1992. Greenland, D.J., Adsorption of polyvinylalcohols by montmorillonite. J. Colloid Sci., 18, 7, 647–664, 1963. Francis, C.W., Adsorption of polyvinylpyrrolidone on reference clay minerals. Soil Sci., 115, 1, 40–54, 1973. Zhao, X., Urano, K., Ogasawara, S., Adsorption of polyethylene glycol from aqueous solutions on monmorillonite clays. Colloid Polym. Sci., 267, 10, 899–906, 1989. Usuki, A., Kojima, Y., Kawasumi, M. et al., Synthesis of Nylon-6-clay hybrid. J. Mater. Res., 8, 5, 1179–1183, 1993.

Composites for Environmental Remediation 29 47. Usuki, A., Kojima, Y., Kawasumi, M. et al., Swelling behavior of montmorrinollitecation exchanged for Ω-amino acid by –Caprolactum. J. Mater. Res., 8, 5, 1174–1178, 1993. 48. Messersmith, P.B. and Giannelis, E.P., Polymer Layered Silicate Nanocomposites: In situ intercalative polymerization of –caprolactone in layered silicates. Chem. Mater., 5, 8, 1064–1066, 1993. 49. Okamoto, M., Morita, S., Taguchi, H. et al., Synthesis and structure of smectic clay/poly (methyl methacrylate) and clay/polystyrene nanocomposites via in situ intercalative polymerization. Polymer, 41, 10, 3887–3890, 1993. 50. Okamoto., M., Morita., S., Messersmith., P.B., Giannelis, E.P., Synthesis and characterization of layered silicate-epoxy nanocomposites. Chem. Mater., 6, 10, 1719–1725, 1994. 51. Vaia, R.A. and Giannelis, E.P., Lattice of polymer melt intercalation in organically modified layered silicates. Macromolecules, 30, 25, 7990– 7999, 1997. 52. Gilmann, J.W., Flammability and thermal stability studies of polymer layered–silicate (clay) nanocomposites. App. Clay Sci., 15, 1–2, 31–49, 1999. 53. Vaia, R.A., Vasudevan, S., Krawiec, W., Scanlon, L.G., Giannelis, E.P., Polymer electrolyte nanocomposites: Melt intercalation of poly (ethylene oxide) in mica-type silicates. Adv. Mater., 7, 2, 154–156, 1995. 54. Kawasumi, M., Hasegawa, N., Kato, M., Usuki, A., Okada, A., Preparation and mechanical properties of polypropylene-clay hybrids. Macromolecules, 30, 20, 6333–6338, 1997. 55. Vaia, R.A. and Giannelis, E.P., Polymer melt intercalation in organically modified layered silicates: Model predictions and experiment. Macromolecules, 30, 25, 8000–8009, 1997. 56. Tanahashi, M., Development of Fabrication Methods of Filler/Polymer Nanocomposites: With Focus on Simple Melt-Compounding-Based Approach without Surface Modification of Nanofillers. Materials, 3, 3, 1593–1619, 2010. 57. Tomasko, D.L., Han, X., Liu, D., Gao, W., Supercritical fluid applications in polymer nanocomposites. Curr. Opin. Solid State Mater. Sci., 7, 4–5, 407–412, 2003. 58. Watkins, J.J. and McCarthy, T.J., Polymerization in supercritical fluidswollen polymers: A new route to polymer blends. Macromolecules, 27, 17, 4845–4847, 1994. 59. Watkins, J.J. and McCarthy, T.J., Polymer/metal nanocomposite synthesis in supercritical CO2. Chem. Mater., 7, 11, 1991–1994, 1995.

30 Composites for Environmental Engineering 60. Watkins, J.J. and McCarthy, T.J., Polymerization of styrene in supercritical CO2-swollen poly (chlorotrifluoroethylene). Macromolecules, 28, 12, 4067–4074, 1995. 61. Carrado, K.A. and Xu, L.Q., In situ synthesis of polymer-clay nanocomposites from silicate gels. Chem. Mater., 10, 5, 1440–1445, 1998. 62. Nakahira, A. and Niihara, K., Strctural ceramics-ceramic nanocomposites by sintering method: Roles of nano-size particles. J. Ceram. Soc. Jpn., 100, 4, 448–453, 1992. 63. Ferroni, L.P., Pezzotti, G., Isshiki, T., Kleebe, H.J., Determination of amorphous interfacial phases in Al2O3/SiC nanocomposites by computer-aided high-resolution electron microscopy. Acta Mater., 49, 11, 2109–2113, 2001. 64. She, J., Inoue, T., Suzuki, M., Sodeoka, S., Ueno, K., Mechanical properties and fracture behavior of fibrous Al2O3/Sic ceramics. J. Eur. Ceram. Soc., 20, 12, 1877–1881, 2000. 65. Tjong, S.C. and Wang, G.S., High-cycle fatigue properties of Al-based composites reinforced with in situ TiB2 and Al2O3 particulates. Mater. Sci. Eng., 386, 1–2, 48–53, 2004. 66. Akita, H. and Hattori, T., Studies on molecular composite. I. Processing of molecular composites using a precursor polymer for poly (P-Phenylene benzobisthiazole). J. Polym. Sci., Part B: Polym. Phys., 37, 3, 189–197, 1999. 67. Akita, H. and Kobayashi, H., Studies on molecular composite. III. Nano composites consisting of poly (P-phenylene benzobisthiazole) and thermoplastic polyamide. J. Eur. Ceram. Soc., 37, 3, 209–218, 1999. 68. Akita, H., Kobayashi, H., Hattori, T., Kagawa, K., Studies on molecular composite. II. Processing of molecular composites using copolymers consisting of a precursor of poly (P-phenylene benzobisthiazole) and aromatic polyamide. J. Eur. Ceram. Soc., 37, 3, 199–207, 1999. 69. Chang, J.H. and An, Y.U., Nanocomposites of polyurethane with various organoclays: Thermomechanical properties, morphology, and gas permeability. J. Eur. Ceram. Soc., 40, 7, 670–677, 2002. 70. Khan, W.S., Hamadneh, N.N., Khan, W.A., Polymer nanocomposites – synthesis techniques, classification and properties, in: Science and Applications of Tailored Nanostructures, One Central Press, United Kingdom, 2016. 71. Ma, R.Z., Wu, J., Wei, B.Q., Liang, J., Wu, D.H., Processing and properties of carbon nanotubes-nano-SiC ceramic. J. Mater. Sci., 33, 21, 5243–5246, 1998.

Composites for Environmental Remediation 31 72. Camargo, P.H.C., Satyanarayana, K.G., Wypych, F., Nanocomposites: Synthesis, structure, properties and new application opportunities. Mater. Res., 12, 1, 1–39, 2009. 73. Mohanty, A.K., Misra, M., Drzal, L.T. et al., Sustainable bio-composites from renewable resources: Opportunities and challenges in the green material world. J. Polym. Environ., 10, 19–26, 2002. 74. Nakamura, R., Goda, K., Noda, J. et al., High temperature tensile properties and deep drawing of fully green composites. Express Polym. Lett., 3, 1, 19–24, 2009.

2 Applications of Composites Materials for Environmental Aspects Pintu Pandit1*, Kunal Singha1, Akshay Jadhav2, T.N. Gayatri2 and Utpal Dhara1 1

National Institute of Fashion Technology, Department of Textile Design, Ministry of Textiles, Govt. of India, Patna, India 2 Institute of Chemical Technology, Mumbai, India

Abstract This chapter deals with all of the apps and utilization of fiber reinforced polymer composite materials in eco helpful engineering with a focus on the green advantages of theirs. These goals might be done by synthesizing physical, natural, and chemical substance facts of engineering and science. Ultimately, our aim is safeguarding and maintain natural resources and human health with to the sustainable development of physical infrastructure, like strategies for wastewater treatment, water supply, renewable energy, solar energy, wind energy, resilient seaside environments etc. Environmental engineering covers a wide variety of purposes involving science and engineering principles to safeguard and improve the natural environment, for instance air, water that is clean, land resources. Likely applications of composites in the upcoming development of different kinds of environmental engineering and domestic products will be in addition discussed in detail in this chapter. Keywords: Composite, fibers, natural resources, sustainable development, environmental engineering

*Corresponding author: [email protected] Shakeel Ahmed and Saif Ali Chaudhry (eds.) Composites for Environmental Engineering, (33–56) © 2019 Scrivener Publishing LLC

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34 Composites for Environmental Engineering

2.1 Introduction Composite is a multiphase substantial produced from a mixture of two as well as elements which differ in alignment or form, that are bonded jointly but maintaining their characteristics and properties. The result of this specific structure is the point that the anew generated material has superior qualities around the separate parts. The fiber reinforcements offer good damping excessive resistance and qualities to fatigue. The certain elements continue to be distinct and diverse within the finished framework, distinguishing composites from combinations of mixtures. The completely fresh information is picked for factors which are many: common examples include supplies that happen to be much more effective, much less weighty, and possibly less expensive in comparison with standard materials. Composites are comprised of certain things called constituent materials. There are two main types of components in a composite material named as- supplies matrix (binder) for reinforcement and constituent fibers or polymers. At least one part of these two types of material is required. The matrix material covers and supports all the reinforcement components by having the comparative proportions. The reinforcements evinced their certain physical and physical qualities to enrich the matrix properties. A synergism needs to be there during making the choices of matrix required to optimally strengthen the framework of any composite materials [1]. The substance parts might be selected on the reinforcement afore or perhaps maybe after the reinforcement written content is positioned in the mould space or perhaps maybe onto the mould top. The matrix constituents understanding is essentially vital. Dependent upon the characteristics of the matrix feature, this unique mixing process can be done in various ways- such as for instance synthetic substance polymerization for only a thermoset polymer matrix, and possibly solidification from the molted charge for a thermoplastic polymer matrix composite. A range of moulding strategies might be useful depending on the end items design requirements. The main problem is to bear this technique for the selected matrix for reinforcement materials. Moreover, another vital issue is to keep a close looking on the availability at the gross level of the component materials. Large amounts or expenditures of automated or fast

Applications of Composites Materials 35 manufacturing technology is most likely could be utilized for validating and manufacturing common hybrid composites made from polyester, vinyl ester, phenolic, epoxy, polyimide, polypropylene, polyamide etc. The reinforcement substances are basic fibers which are widely in used in textile and fiber industries. The various techniques for example- 60 % resin along with 40 % fiber in addition with vacuum infusion may offers a final composite with a better rigidity and hardness. The mechanical modulus of these products are greatly based on this matrix to fiber ratio. For example-wood is considered a natural composite of cellulose fibers inside a matrix of lignin based composite [2,3]. Standard engineered composite materials for earth consist of reinforced concretes and rigid bodies (composite wood as plywood, reinforced plastics like polymer or maybe fiberglass, ceramic matrix composites and metal matrix composites) was reinforced by fiber more advanced composite materials. There are various usages of composite materials spread over a wide of ranges as spacecraft and aircraft, marine engineering, civil engineering, agriculture and greenhouse, acoustic insulators, wind energy, solar energy and ecofriendly engineering pile up etc.

2.2 History of Composites for Eco-Friendly Engineering Most likely the earliest made composite stuffs were straw and mud mixed to make bricks for building structure. Primeval brick making was realized by Egyptian tomb portraits. Wattle and daub are among possibly the eldest male made composite materials by 6000 years old. Concrete is a amalgamated material, plus is used greater than every other male made the substance in the earth. Woody shrubs like both real wood from trees and such plant life as palms and bamboo, can yield natural composite that has been used prehistorically by humanity and continue being utilized commonly in creating and scaffolding [4]. Among the usual plus common majority of the composites are fiberglasses, where small glass fibers are embedded inside a polymeric substance (usually an epoxy or perhaps maybe polyester). The glass fiber is tough and stiff relatively (but besides brittle),

36 Composites for Environmental Engineering while the polymers are ductile (weak and also flexible). So the resultant fiberglass is fairly flexible, ductile, strong and stiff in nature [3].

2.3 Composites for Greenhouses A green home is a framework with walls in addition to top created chiefly of transparent info, like glass, in what plants needing regulated climatic conditions are cultivated. Numerous viable glass greenhouses are hi-tech manufacturing facilities for vegetables or flowers. The glass greenhouse is packed with gear like screening installations, cooling, lighting and also may be handled by a laptop computer to adjust conditions for vegetable growth. Different techniques are utilized to assess best amounts in addition to comfort ratio of greenhouse microclimate (i.e., air temperature, relative humidity in addition to vapor pressure) to have the ability to reduce production danger just before looking after a particular crop. Composite with less reflective glasses are usually less effective but cheaper and anti-reflective coated with best economic advantages. Ventilation is among the most necessary components in increasing greenhouse trends.

2.4 Polymers have been Reinforced by Fiber (FRP) for Greenhouse FRP is a profitable material option that is idyllic for various types of construction. Fiber Reinforced Polymer (FRP) is common within the building business due to the layout flexibility, affordability, nonconductivity, low maintenance considerable strength-to-weight ratio, UV resistance and flame retardance. FRP constituents for Greenhouses are structural or building component such as angles, channels, I-beams, square round tubes, gratings, walkways, stairways and panel.

2.4.1 Composites Employed in Controlling Humidity in the Home which is Green Humidity regulatory masses of biological and inorganic substances are examined to replace brick for greenhouse structure which

Applications of Composites Materials 37 employs the ability of the dampness controlling supplies to raise and minimize the fluid to solve today’s issues of humidity controlling strategies in the greenhouse. The formulation of the raw resources of the moisture regulatory brick is done by making sure of the proportion of preservative in the raw materials and also by checking the impact of relative humidity onto the resources. The creation procedure for composite and various moisture controlling techniques has been discussed in that chapter. The ratios of entire raw materials of the bricks for maximum moisture are acquired through the assessments on the ability of the composite humidity regulatory blocks of different percentages of raw constituents. The composite components provide the great advantage of environmental protection, energy and heat saving operation. This can help in securing the preservation in many greenhouse-builded applications.

2.4.2 Composite Films for Optical Transmission of Greenhouse It has been evident that equally low-density polyethylene (LPDE) and linear very minimal density polyethylene (LLDPE) can place in much better hand power and excellent environmental stress resistance when as opposed with few other polymers [1]. Generally, LDPE is applied for a lot of materials as a demonstration, trash bags in addition to greenhouse films whereas LLDPE is perfect for farming uses. Blended LDPE or LLDPE film are often used as covering content due to their ability to display a gentle window in the variety of light which is noticeable, that’s a benefit for just about any plant life could be utilized in picture synthesis. Thermal power is often accumulated inside the greenhouse throughout the day and in addition is created to nearby at night, commanding to good winter suggest which would provide regular development for vegetable cultivating inside the greenhouse [5].

2.5 Composites Employed in Acoustic Applications Over the last several years, there is still a growing demand for improving the inner noise and inside the sound of railway, aircraft,

38 Composites for Environmental Engineering automobile, and developing compartments. Interior sound impairs person’s health and results in a drop in safety that is active plus passenger comfort implementation [6,7]. Nowadays sound pollution is now the last pollution source containing excellent bad influences on the environment, human health, and economy. The right way to reduce the damages of sound is now a vital issue. Generally, active management and also passive control [7] is provided through the ways of managing noise. Though it’s capable of just deal with the sounds linked to a narrow frequency range, the former is really accomplished by decreasing the generation of sound at the areas of sound sources. The passive management is often attained through the utilization of higher sound absorption materials, which could be utilized to absorb sounds linked to an extensive frequency range by efficiently dissipating power that is good on the process of propagation of the sound wave. The application of good absorbing materials is among the current successful sound control technologies. The insulation materials and also regular industrial sound absorption are in fact mineral fibers, foam, in addition to the composites of theirs. Nevertheless, the uses of such thing is costly as energy consumptive and also provides much greater value on the parts, that impacts the structural integrity of theirs. Sandwich structure composites happen to get widely employed in aerospace, construction and transportation along with anew energy fields as load-carrying parts by reason of the excessive strength-to-weight ratio of theirs. Sandwich construction composites are designable, multifunctional and also additional characteristics might be offered beside sustaining with appropriate design, for instance, acoustic absorption impact tolerance, radiation resistance and thermal isolation etc. Natural fibers for instance ramie, jute, knead, etc. Reinforced composites have drawn a good deal of interest from engineers and material scientists lately due to the great mechanical properties of theirs, light in body weight, friendly and biodegradable environmentally [8,9]. Nevertheless, natural fibers, as fibrous porous elements, definitely were keen on yielding the assortment of new sound absorption structures in new years. As a kind of fibers, natural fibers are intended having a very similar mechanism for acoustic absorption as more conventional synthetic fibrous elements, like cup fiber and mineral wool. The systems of excellent absorption in porous fiber product are essentially the viscous effects

Applications of Composites Materials 39 as an outcome of the internal friction between fiber structure and airflow, after which winter losses due to heat transfer among many fibers [10]. Nowadays, increasing interest has centered on earth environmental friendliness, like inside floor panels in aerospace industry, highspeed trains, and automobiles. Compatible components that may be reused and maybe have much small energy for creation and also add minimal greenhouse gas secretions. By using organic substances as face sheets or maybe core sources for sandwich structures would provide fatigue properties with great load bearing. Furthermore, this particular system type provides great sound absorption characteristics when as opposed with the regular metallic plus laminated composite structural users [11,12]. Holistic comprehension the acoustic attenuation process of different porous resources is provided by managing sound by sound absorption. The accessible industrial sound absorptive constituents utilised in outdoor and indoor uses might be grouped as fibrous, cellular and granular. Fibrous components could be possibly natural either synthetic. The acoustic sections from organic fibers are not perilous to human health and also far better ecofriendly than any traditional manmade fibers [13]. As a result, usages of natural aided composites are created such a huge interests and hopes among the manufacturers and engineers to look for alternative substances from organic fibers as a substitute for artificial fibers. The blend of natural or conventional fiber with rubbery granular substances proved as an considerable audio absorption overall performance at less frequency area in comparison to either existing organic fiber or maybe granular composites. The objective of natural fiber based composite or green composite is to minimum the impact and health hazard troubles by maintaining recyclable standard and leading to environmental pollution by stopping the emission of CO2 gasoline responsible for climatic change abruptly in daily life [14–16]. To be able to eliminate these issues fibro granular composites are made to make the planning of sustainable and ecofriendly composites with the mixture of all natural fiber with biogranular elements. These fibrogranular composites show encouraging basic functionality within the evaluation of many outside and indoor applications [17,18].

40 Composites for Environmental Engineering

2.6 Natural Fiber Composites Natural fiber-based composites are biodegradable, little, much less expensive, nontoxic, together with nonabrasive attributes and presume as the most substitute for synthetic fibers for acoustic absorption reasons. The organic fibers with great physical attributes are proved as top quality composites with economical and environmental advantages for example The fibers of coir, corn, paddy, sisal, banana, fiber glass, mineral wool, and glass wool are excellent examples of artificial fibers which can act as potential solutions for manufacturing of acoustic absorbers [3,19]. Natural fiber reinforced resin/polymer composites have attained a good deal of interest as an outcome of the small, cost-efficient, abundant, biodegradable and also environmentally friendly by property. Furthermore, these substances are usually more affordable, ecofriendly better than pure glass fiber reinforced composites [20]. To be able to assist the quality of natural fibers chemical substance changes of the fibers are carried out before composite production to remove these limitations. It was proved that mercerization or maybe alkaline treatment can reduce the fiber diameter by upgrading the adhesive quality of natural fibers [21]. The increment of fiber diameter really helpful for sound absorption due to the enhancement of fiber tortuous path and greater surface area, which subsequently improves the air flow resistivity of fibrous content. The expansion of air flow resistivity results in loss of power that is good by friction of sound waves with air particles and therefore boosts extremely minimal frequency sound absorption [22].

2.6.1 Pretreatment of Natural Fiber To be able to achieve fiber body, fiber quality, additionally to a far better fiber-matrix adhesion within the composite, pretreatment of all natural fiber is necessary for internet business use in parallel with synthetic fiber. Many pretreatment techniques will be found by you there to enable you to tune the fiber depending on the research needs. Mercerization or maybe alkaline treatment, plasma therapy, then graft copolymerization is provided by examples. Among them, mercerization or maybe alkaline treatment serves the objective of

Applications of Composites Materials 41 the evaluation, as this particular method lowers the fiber diameter. This is a typical process of yielding good quality fibers. Mercerization lifts the surface unevenness of fiber through the elimination of many important things as lignin, pectin, and also hemicelluloses of the fiber. Though removing these items reduces the acoustic absorption performance of the content material, it provides for more effective fiber binder interface adhesion, fiber wellness, sustainability, antifungus quality and most significantly decreases the diameter of the fibers [23,24]. Few of natural bioresources can also be utilized as natural pretreatment, dyeing and functional finishes to improve natural fiber performance for better composite materials as per end applications [25–28].

2.6.2 Factors Impacting on Bodily Functioning of Natural Fiber Composites Fiber selection criteria are very crucial while manufacturing a good composite, for example these criteria are such as matrix selection, fiber content, fiber dispersion, fiber orientation, interfacial strength, fiber type, extraction method, harvest time, aspect ratio, treatment, composite manufacturing process and porosity etc.

2.6.2.1 Fiber Selection Fiber style is often categorized dependent upon its origin: plant, mineral or animal. Most vegetable fibers include cellulose like the main structural part of theirs, while animal fibers mostly entail of protein. Though mineral-based natural fibers had been earlier used extensively in composites, these are now stayed away from due to associated health issues (carcinogenic by ingestion or inhalation) and banned in several countries. Generally, greater strengths and stiffness are offered with the larger performance cultivate fibers than the found animal fibers. An exception to this is silk, that might have truly high strength, but is pretty costly, has decreased stiffness and is less found [29,30]. This helps make plant-based fibers best to be worn in composites with structural specifications, so the emphasis on the evaluation. Furthermore, plant fiber may suitably be developed in several locations and in addition could be harvested after

42 Composites for Environmental Engineering short periods. In general, higher productivity is attained with varieties having better cellulose written content along with with cellulose microfibrils lined up a lot more in the fiber path which is apt to occur in bast fibers (e.g. flax, hemp, kenaf, jute in addition to ramie) that have far better structural requirements in providing support for the stalk over the veggie [31].

2.6.2.2 Matrix Selection The matrix is an important part of a fiber reinforced composite. A barrier against adverse locations are supplied by it, protects the surface part of the fibers from physical abrasion and that transfers load to fibers. The most used matrices currently used in NFCs are polymeric as they are light weight and in addition could be prepared at heat which is reduced. Thermoplastic polymers and both thermoset are used for matrices with good fibers [2].

2.6.2.3 Interface Strength Though natural fibers come from inexhaustible resources also the polymer composites reliant on them are earth friendly, additionally, you will find a few drawbacks. They are connected with the application of unmodified or raw fibers within preparation of the composites to remove various disadvantages are as quality differences, better moisture absorption and smaller thermal balance of the unmodified fibers [32,33].

2.6.2.4 Fiber Orientation The best hand properties may typically be achieved for composites in case the fibers are lined up parallel to the line of applied load. Nevertheless, that is tougher obtaining alignment with organic fibers than for continuous synthetic yarns. Some alignment is managed during injection moulding, driven by matrix viscosity and mould design. Wind power could be the very best example of unlimited power source. Wind power is completely clean, ecofriendly and inexhaustible environmentally and may serve as an substitute to fossil fuels. The essential model of utilizing renewable

Applications of Composites Materials 43 energy is actually dependent on the simple fact that it’s in a position to minimize greenhouse gases and pollution. Natural fiber reinforced composites develop a great group of things which not just have excellent manual qualities but may furthermore be biodegradable in nature.

2.6.3 Jute-Coir Composites for Constructions All wooden products can be used as an option construction business. That needs the generation of coir ply sheets with focused jute as coir and waste rubber timber inside. A very skinny layer of jute fibers filled with phenolic resin is utilised for enhanced appearance plus to be able to create a wood as finish. The composite ply coir boards (jute rubber wood coir) as natural fiber and plywood substitute reinforce boards (jute coir) can be applied as synthetic composite substitute for manufacturing of false ceiling, roofing, furniture, partitioning, surface paneling, furniture, wardrobe and cupboards. These boards are utilized as doors mounts as an additional to traditional material as wood, steel etc. [2,3].

2.6.4 Bamboo Composites for Construction The bamboo-based composites might be utilized in creating sector for flooring tiles, blocks, false ceilings, furniture and partition walls etc. with laminated or polymerized surface. Pre-fabricated housing components for shelters, sheds, huts, pyramids, cubicles etc. are fabricated by consuming bamboo composites. These factors include of beams, structural frames, columns and rafters and trusses etc. and are erected by cladding with nuclear, biological and functional protective aided fabric sheets. They are suitable for remote and distant places and a great deal suitable for hill forts, remote beaches, inclement weather stations, regular as well as unconventional traveler areas, farmhouses, little islands and retreats. Some other product that is constructed with bamboo based polymer resin embellished components. Due to the organic weightlessness of the bamboo some fantastic composite matrix can be produced with the great bo the attribute of bamboo, so it becomes less heavy when compared with a different wood and plywood boards. Bamboo laminates might change timber

44 Composites for Environmental Engineering in most uses as door, furniture, window and also used in making of partition frame, cabinet, wardrobes and flooring etc.

2.7 Effective Factors for Low Frequency Acoustic Absorption 2.7.1 Fiber Size Fiber diameter is most likely most crucial physical geometrical parameter for enhancing the sound absorption overall functionality for any fibrous material. The decrease in fiber diameter leads to a growth in the benefits of sound absorption coefficient. This is since more fibers should attain identical volume density at similar thickness of the test material. This results to a tortuous path and higher airflow resistance. As an end result, the acoustical performance of the sample material improves as an outcome of the viscous friction through air vibration. The accession of thinner fibers as a consequence of the reduction in fiber diameter results in a remarkable certain surface area and far more micropores within the exact same volume density of the sample. This raises the value of the sound absorption coefficient because of more friction of air molecules with a larger surface area. Additionally, small fiber moves much better in comparison with thick fiber in waves that are good, which results in vibration in the environment, which enhances absorption working with more viscous losses due to air vibration [34,35]. Fiber diameter is an important parameter in improving the audio absorption within the lower frequency region. The considerable development in lesser frequency absorption was found due to the reduction in coir fiber diameter inside the numerical simulation of due to the assortment of fiber sizes on constant thickness of the test material. Finer fiber with lowered diameter absorbed the sound much more successfully than the large, coarse fiber. The finer fibers better the sound absorption overall functionality of nonwoven fabric content by lessening the prospective connectivity of pores. Generally there appeared to be a gradual increase along with a difference in the good on sound absorption coefficient with the lessening of fiber diameter towards the lower frequency region [34].

Applications of Composites Materials 45

2.7.2 Feed Size The characteristic impedance plus propagation constant with characteristic porosity, particle dimension, tortuosity, density of matrix base is very much important factors to be considered while empirically designed a new composite fabric. A reliable prediction of the acoustic performance of a loose granular blend of grain base like husk was described by the research [36]. The usefulness of elmer rice husk and also buckwheat husk as sensible absorbing materials have been shown by them. They learned that the benefit of the sound absorption coefficient of grain husk is 0.5 plus buckwheat husk is 4.5 at 500Hz and 40mm thickness [37]. The flow resistivity is directly proportional to the inner surface area of the granular composite material, and the inner surface area is inversely proportional to the feed size. Additionally, it confirmed that unconsolidated granulates of feed sizes and consolidated content of grain size contribute bigger flow resistivity, on the issue of utilizing the binder at an excellent ratio. The statement of theirs might be clarified through the basic fact that smaller sized grains display bigger flow resistivity than larger grains, bringing about increased acoustic absorption general performance [38]. There is another idea that clarified that the reduced sized grains display bigger flow resistivity than the larger grains, leading to increased acoustic absorption basic performance for every grain types.

2.7.3 Majority Density The density of a chemical is generally a significant component governing its sound absorption traits. The analysis of materials density is critical, as the present analysis is dealing with the collective density of two materials like fibrous and granular material. It is reported the elevated sample density is going to cause an increase in sound absorption at high frequency regions and medium. They had proved that with increment of the sample density is prominent with the increment of the volume of fibers/area for a matrix in a composite material. As an end result, energy damage of sound waves will increase as an outcome of the expansion of area friction that typically results to an increase in fine absorption performance [32]. The effect

46 Composites for Environmental Engineering of most density was noticed in the acoustic performance of bamboo wool materials. The improved majority density of the bamboo wool content moved the great worth of the sound absorption coefficient from the substantial on the reduced frequency range.

2.7.4 Sample Layer Thickness Based on basic guidelines of absorption phenomena inside a porous material, the absorption is enhanced by a lot of dissipative technique of viscosity and thermal conduction between the matrix and fiber layers inside the composite. This much better sound absorption is due to the better thickness of the test material. The significant part of fiber level thickness on acoustic absorption of fresh and industrial coir fiber. Setup of the Johnson Allard rigid frame layout to compute the acoustic absorption overall functionality of coir fiber at different thicknesses. It was found that improving the coir fiber layer thickness improves the absorption and moves the absorption peak towards the lower frequency region [33].

2.8 Composites Employed in Wind Energy The search for alternative sources of electricity and technological innovation that will help tap electrical power from sources hitherto not being used, has become especially relevant in the wake of the energy crisis rural sector. Blowing wind power is sustainable and clean source of energy. The wind energy industry is among the greatest proprietors of composite materials. Composites are mostly present in two components: the nacelle and the blades. While other hybrid combinations happen to be suggested, carbon/glass fiber hybrid composites are the solution that is beginning to be utilized by turbine manufacturers. The wind generator industries are constantly focusing on the enhancement of light in body weight, cost potent and also green-friendly materials due to the development of wind turbine blades. The quantity of correct blade materials plays a significant role which determines the final effectiveness of a wind turbine blade.

Applications of Composites Materials 47

2.9 Composites Used in Wind Turbines Some variants in the framework of wind turbines are developed by rapid improvements in material technology. In wind structures, cutters are a surely crucial part of system effectiveness. Generally, composite materials are constituted of the metallic, organic or inorganic base structural mechanisms. Those are widely known as particulates, fibers, stamps, matrix layers. Geometrical shapes are restricted by those structural components. Actual functions of the matrix as being a quantity element is to be able to create a dispersion of extra structural ingredients as fibers, particulates, stamp in the personal framework of its, to create a phase effect among those components. Components which are in composite materials are sorted out inside each other, they have passive action chemically. Nevertheless, especially, in metallic systems in minimal quantities, several magnitude dissolutions and interfacial reactions affecting composite qualities among components could be discovered. Purpose of composite materials appear to be on wind turbine blades may be tended due to the sophistication of one or maybe perhaps a number of the physical, chemical or even physical properties as humidity, heat, and chemical supplies oxidation resistance may decides its results pertaining to green effects as in humidity or in absorption [39–41].

2.9.1 Impact of Wind Hit on the Composite Material In wind turbine technology for halting unforeseen effects affected by wind hit originated from outside environment information is really apt to give a response or even maybe many convenient responds. Based upon the planned location and use where the system is developed probable attacks imposing on content could possibly arouse in several methods that can be various. Against that, respond offered to hit relies on the material. Strike electrical power in composite materials simply could be entrapped by flexible deformation and also a number of damage systems (fiber break, matrix rest and delimitation). In the very long term, polymer composites are thought to take place in turbine blade solutions. Furthermore, with classically

48 Composites for Environmental Engineering recognized composites bright composites in turbine engineering may be assumed in an economical way.

2.10 Composite Materials for the Marine Environment Marine and manufacturing locations subject materials to powerful situations that demand optimum and maintenance-free functioning over extended stages of operation. By using current composite materials technology to industrial marine engineering various difficulties like fatigue can be eliminated by lowering down the maintenance hazards due to sea water interaction with the various hard part of the ship. Composite materials happen to get applied completely in a marine environment after the late 1950’s in addition to their life expectancy is successfully found in applications as sailing as well as motor vessels, buoys, pontoons, and buoyancy. The great bulk of top quality craft nowadays is produced from mixtures of composite materials coupled using a number of different manufacturing processes. Composite materials are broadly defined as those in which a binder is reinforced with strengthening materials. In terms that are contemporary, the binder is generally a resin, as well as definitely the reinforcing material consists of cup strands (fiber glass), aramid fibers or maybe carbon fibers. Composites provide the benefits connected with a much better strength-to-weight ratio than constant wood or steel methods, as well as they involve lower levels of ability to produce a good hull surface on a semi-industrial scale. The application of FRP composites to maritime crafts was initially pressed by a need for little, good, corrosion resistant long lasting naval boats. Many of these first applications are pushed by the necessity to overcome corrosion problems came across with steel or maybe environmental degradation or maybe aluminum alloys suffered by wood. The cost of carbon fiber falls as production bulks development so the accessibility of sheet carbon fiber (and other profiles) is more prevalent in boat/ship production. Composite materials and technology science are in fact improving promptly and carbon nanotube and epoxy mixtures are integrated by brand-new composites.

Applications of Composites Materials 49 Not a long time ago, a bit naval boat with a hull made utilizing carbon nanotubes was delivered as a concept task. A rising an element in boat construction will be performed by strength, lightness, durability and ease of manufacturing process. Despite the new composites, fiber reinforced polymer composites more and more promising for many years to come.

2.11 Composite Materials for Aerospace Engineering Composite materials are largely a combination of two plus unlike elements that are used collected in an attempt to merge greatest qualities or maybe impart a recently available variety of features that neither of the constituent substances is able to reach on their own. Engineering composites are hoarded from specific plies that use the kind of frequent, straight fibers (eg. carbon, glass, aramid etc.) lodged in a wide range polymer matrix (eg. phenolic, polyester, epoxy etc.). The utilization of fiber reinforced composites has become a more and more appealing choice to the common metals for a lot of aircraft components primarily as an outcome of the greater strength of theirs, durability, corrosion resistance, resistance to fatigue and harm tolerance characteristics. Composites provide better freedom since the content might be personalized to meet up in the layout needs and furthermore they offer extensive weight advantages. Carefully created individual composite parts, currently, are approximately twenty 30 % lighter than their regular metal counterparts. For light aircraft and carefully loaded structural elements. Numerous forms of composites are generally put on to the aerospace industry. For example, composites had been originally used for military aircraft during World War II. Nowadays, they are used for private planes plus contemporary industrial aircraft in the aerospace industry. It is essential that you simply be mindful that the three most regular pre-existing types of composites are reinforced with fiber glass, aramid fiber, and carbon fiber. Aramid fiber is a training course of heart resistant and effective artificial fibers. They are employed in military aerospace and applications, for ballistic ranked body armour cloth and ballistic composites, in motorcycle tires, and as an asbestos replacement [41].

50 Composites for Environmental Engineering

2.12 Composites Materials for Civil Engineering Composites may perhaps gain civil engineering. Advantages which composites provide are combined with the particular bodily limits of civil engineering an interesting progress has the ability to happen. Composites are usually a part of the information developing and foundation for civil engineering projects. During the last thirty years of composite materials, plastics and also ceramics are really the dominating emerging materials. The volume and number of applications of composite materials will continue to grow continuously, enquiring and conquering brand new markets relentlessly. Modern composite materials constitute a sizable portion of the engineered resources market. As the years go by, civil engineering has created us realize the benefits of using composite materials in construction. There is been a sizable increase in the quantity of structures in developing and building which use composite materials. Furthermore, with increased demand on power, safety and trustworthiness it has become essential for a great deal of industries to utilize composites in civil engineering. Composites are in trend in the construction industry over sine a long time. Furthermore, difficulties that entail building reinforced parts that are competent to get over disasters as earthquakes and hurricanes are faced by civil engineering today. this needs the revolutionary use of composite materials in structural systems and pre-existing buildings. Composites are used effectively in creating concrete buildings more earthquake resilient around the earth. It is anticipated that composite engineering is able to get a lot more useful highways into the civil engineering allowing it to conduct a much more essential component in pressing the prospective future of the building and building system on the boundaries that are an essential component for environmental engineering.

2.13 Composite Materials Employed in Solar Energy Panels Solar energy is going to be the world’s most plentiful renewable source of power. It is potential that’s amazing to modify the

Applications of Composites Materials 51 exhausting fossil fuels to get the culture of ours. Current photovoltaic and photocatalytic strategies are almost completely reliant on semiconductor materials. To enhance the usefulness of these devices for solar energy programs, various methods are designed. Considerable work was based on the enhancement of semiconductor/ biomolecular composites for changing sunlight to electricity and fuels. A fast increase in human population and also worldwide economic development make a successful demand for power, although the fossil fuel reserves that we rely a great deal on are depleting. Together with the substantial difference between demand and supply, use of nonrenewable fuels, in addition, causes resultant green problems, like air pollution, climate change triggering weather changes, and also the destruction of biodiversity. To be equipped to preserve sustainable global development, exploring limitless power with very little undesirable environmental consequences is essential. The promising applicants need to be abundant, cheap and environmentally clean, along with for sale on earth. Among the organic and natural inexhaustible energy as biomass power, tidal, ocean thermal, geothermal, wind, and sunshine, the solar energy is considered the appealing choice [42]. Furthermore, through molecular engineering, it is possible to tune the optical and electrical characteristics of organic molecules to a better match for the goal of solar energy conversion. In truth, a wide variety of organic and inorganic nano composites are often be employed in the device fabrication phone system to improve the solar power harvesting and additionally the charge transport processes [43]. Among many of the benefits of solar energy panels, the most essential element is that solar energy is truly a renewable source of energy.

2.14 Conclusions These goals might be done by synthesizing physical, natural, and chemical substance facts of engineering and science. Natural resources with the sustainable development of physical infrastructure, renewable energy, solar energy, wind energy, resilient seaside environments etc. Environmental engineering covers a wide variety of purposes involving science and engineering principles to safeguard and improve the natural environment, for instance air, water

52 Composites for Environmental Engineering that is clean, land resources. Likely, improved and performance enhancement applications of composite materials in the upcoming development of different kinds of environmental engineering.

References 1. Myriounis, D., Role of segregation and precipitates on interfacial strengthening mechanisms in metal matrix composites when subjected to thermo-mechanical processing, Sheffield Hallam University, Research Archive, U.K., 2009. 2. Das, S., Basak, S., Pandit, P., Singha, A.K., Hybrid Bast Fiber Strengthened Thermoset Composites. Thermoset Compos. Prep. Prop. Appl., 38, 112, 2018. 3. Jadhav, A.C., Pandit, P., Gayatri, T.N., Chavan, P.P., Jadhav, N.C., Production of Green Composites from Various Sustainable Raw Materials, in: Green Composites. Textile Science and Clothing Technology, Muthu S. (ed.), pp. 1–24, Springer, Singapore, 2019. 4. Shaffer, G.D., An archaeomagnetic study of a wattle and daub building collapse. J. Field Archaeol., 20, 59–75, 1993. 5. Dunne, R., Desai, D., Sadiku, R., Material characterization of blended sisal-kenaf composites with an ABS matrix. Appl. Acoust., 125, 184– 193, 2017. 6. Thomas, S., Surgical dressings and wound management, Dr Stephen Thomas, Medetec Publications, Cardiff, South Wales, U.K., 2010. 7. Kittas, C., Tchamitchian, M., Katsoulas, N., Karaiskou, P., Papaioannou, C.H., Effect of two UV-absorbing greenhouse-covering films on growth and yield of an eggplant soilless crop. Sci. Hortic. (Amsterdam), 110, 30–37, 2006. 8. Briassoulis, D., Aristopoulou, A., Bonora, M., Verlodt, I., Degradation characterisation of agricultural low-density polyethylene films. Biosyst. Eng., 88, 131–143, 2004. 9. Dintcheva, N.T., La Mantia, F.P., Acierno, D., Di Maio, L., Camino, G., Trotta, F., Luda, M.P., Paci, M., Characterization and reprocessing of greenhouse films. Polym. Degrad. Stab., 72, 141–146, 2001. 10. Cemek, B. and Demir, Y., Testing of the condensation characteristics and light transmissions of different plastic film covering materials. Polym. Test., 24, 284–289, 2005. 11. Papadopoulos, A.P. and Pararajasingham, S., The influence of plant spacing on light interception and use in greenhouse tomato

Applications of Composites Materials 53

12.

13. 14.

15.

16. 17.

18.

19. 20.

21.

22.

23.

24.

(Lycopersicon esculentum Mill.): A review. Sci. Hortic. (Amsterdam), 69, 1–29, 1997. Liu, J., Bao, W., Shi, L., Zuo, B., Gao, W., General regression neural network for prediction of sound absorption coefficients of sandwich structure nonwoven absorbers. Appl. Acoust., 76, 128–137, 2014. Arenas, J.P. and Crocker, M.J., Recent trends in porous soundabsorbing materials. Sound Vib., 44, 12–18, 2010. Maderuelo-Sanz, R., Barrigón Morillas, J.M., Martín-Castizo, M., Gómez Escobar, V., Rey Gozalo, G., Acoustical performance of porous absorber made from recycled rubber and polyurethane resin. Lat. Am. J. Solids Struct., 10, 585–600, 2013. Maderuelo-Sanz, R., Nadal-Gisbert, A.V., Crespo-Amorós, J.E., Parres-García, F., A novel sound absorber with recycled fibers coming from end of life tires (ELTs). Appl. Acoust., 73, 402–408, 2012. Pfretzschner, J., Rubber crumb as granular absorptive acoustic material, Pfretzschner Jaime, Madrid, Spain, 2002. Mahzan, S., Ahmad Zaidi, A.M., Arsat, N., NM Hatta, M., Ghazali, M.I., Rasool Mohideen, S., Study on sound absorption properties of coconut coir fiber reinforced composite with added recycled rubber. Int. J. Integr. Eng., 2, 29–34, 2010. Mamtaz, H., Fouladi, M.H., Al-Atabi, M., Narayana Namasivayam, S., Acoustic absorption of natural fiber composites. J. Eng., 1–11, 2016. Borlea, A., Rusu, T., Vasile, O., Investigation composite materials for its sound absorption properties. Rom. J. Acoust. Vib., 9, 123, 2012. Juliá, E., Segura, J., Nadal, A., Gadea, J.M., Crespo, J.E., Study of sound absorption properties of multilayer panels made from ground tyre rubbers. Fascicle Manag. Technol. Eng., 1, 147–150, 2013. Kalia, S., Kaith, B.S., Kaur, I., Pretreatments of natural fibers and their application as reinforcing material in polymer composites—A review. Polym. Eng. Sci., 49, 1253–1272, 2009. Tsujiuchi, N., Koizumi, T., Ohshima, Y., Kitagawa, T., An optimal design and application of sound-absorbing material made of exploded bamboo fibers, in: Conf. 2005, IMAC-XXIII Conf. Expo. Struct. Dyn, pp. 1–7, 2002. Asdrubali, F., Survey on the acoustical properties of new sustainable materials for noise control, in: Proc. Euronoise, European Acoustics Association, Tampere, 2006. Turkiewicz, J. and Sikora, J., Sound absorbing materials from recycled rubber products. Mech. Control., 32, 3, 117–121, 2013.

54 Composites for Environmental Engineering 25. Teli, M.D. and Pandit, P., A Novel Natural Source Sterculia foetida Fruit Shell Waste as Colorant and Ultraviolet Protection for Linen. J. Nat. Fibers., 15, 3, 2018, 337–343, 1–7, 2017. 26. Teli, M.D. and Pandit, P., Development of thermally stable and hygienic colored cotton fabric made by treatment with natural coconut shell extract. J. Ind. Text., 48, 1, 87–118, 2018. 27. Pandit, P., Gayatri, T.N., Maiti, S., Green and Sustainable Textile Materials Using Natural Resources. Green Sustain. Adv. Mater. Process. Charact., 1, 213–261, 2018. 28. Pandit, P. and Nadathu, G.T., Characterization of Green and Sustainable Advanced Materials. Green Sustain. Adv. Mater. Process. Charact., 1, 35–66, 2018. 29. Teli, M.D. and Pandit, P., Multifunctionalised silk using Delonix regia stem shell waste. Fibers Polym., 18, 1679–1690, 2017. 30. Teli, M.D. and Pandit, P., Novel method of ecofriendly single bath dyeing and functional finishing of wool protein with coconut shell extract biomolecules. ACS Sustain. Chem. Eng., 5, 9, 8323–8333, 2017. 31. Das, S. and Bhowmick, M., Mechanical properties of unidirectional jute-polyester composite. J. Text. Sci. Eng., 5, 1, 2015. 32. Koizumi, T., Tsujiuchi, N., Adachi, A., The development of sound absorbing materials using natural bamboo fibers. WIT Trans. Built Environ., 59, 1–10, 2002. 33. Nor, M.J.M., Ayub, M., Zulkifli, R., Amin, N., Fouladi, M.H., Effect of different factors on the acoustic absorption of coir fiber. J. Appl. Sci., 10, 2887–2892, 2010. 34. Coates, M. and Kierzkowski, M., Acoustic textiles–lighter, thinner and more sound-absorbent. Tech Text Int., 11, 15, 2002. 35. Ingard, K.U., Notes on sound absorption technology (Book), NY Noise Control Found, Poughkeepsie, 1994, 1994. 36. Voronina, N., Acoustic properties of fibrous materials. Appl. Acoust., 42, 165–174, 1994. 37. Sakamoto, S., Takauchi, Y., Yanagimoto, K., Watanabe, S., Study for sound absorbing materials of biomass tubule etc. J. Environ. Eng., 6, 352–364, 2011. 38. Swift, M.J., Bris, P., Horoshenkov, K.V., Acoustic absorption in recycled rubber granulate. Appl. Acoust., 57, 203–212, 1999. 39. Vardar, A. and Eker, B., Mathematical modelling of wind turbine blades through volumetric view. Wind Struct., 9, 493–503, 2006. 40. Vardar, A. and Eker, B., The wind tunnel measuring methods for wind turbine rotor blades. Wind Struct., 7, 305–316, 2004.

Applications of Composites Materials 55 41. Zhou, H.F., Dou, H.Y., Qin, L.Z., Chen, Y., Ni, Y.Q., Ko, J.M., A review of full-scale structural testing of wind turbine blades. Renew. Sustain. Energy Rev., 33, 177–187, 2014. 42. Baxter, J., Bian, Z., Chen, G., Danielson, D., Dresselhaus, M.S., Fedorov, A.G., Fisher, T.S., Jones, C.W., Maginn, E., Kortshagen, U., Nanoscale design to enable the revolution in renewable energy. Energy Environ. Sci., 2, 559–588, 2009. 43. Mbuyise, X.G., Arbab, E.A.A., Kaviyarasu, K., Pellicane, G., Maaza, M., Mola, G.T., Zinc oxide doped single wall carbon nanotubes in hole transport buffer layer. J. Alloys Compd., 706, 344–350, 2017.

3 The Application of MechanoChemistry in Composite Preparation S. C. Onwubu1*, P. S. Mdluli2, S. Singh3 and M. U. Makgobole4  1

Department of Dental Sciences, Durban University of Technology, South Africa 2 Department of Chemistry, Durban University of Technology, South Africa 3 Discipline of Dentistry, University of KwaZulu-Natal, South Africa 4 Chiropractic and Somatology, Durban University of Technology, South Africa

Abstract Traditional dependency on solvent in most chemical reaction is becoming less viable and sustainable in the event of climate change facing the world. In this aspect, mechanochemistry offers an advantageous prospect in composite material preparation. Its use in the synthesis of hydroxyapatites and eggshell powder for various medical and dental applications has added to the field of chemistry a new insight to chemical reactivity and material synthesis. The aim of this chapter was to provide a comprehensive overview on the advances made in the mechanochemical process of material preparation. Keywords: Mechanochemistry, preparation, composites

3.1 Introduction In recent decade, science, engineering, and technology have witnessed unprecedented advances in nearly every facet of human life. In medicine and dentistry, these advances is buoyed by the discovery and introduction of smart material having characteristics that *Corresponding author: [email protected] Shakeel Ahmed and Saif Ali Chaudhry (eds.) Composites for Environmental Engineering, (57–68) © 2019 Scrivener Publishing LLC

57

58 Composites for Environmental Engineering mimic the natural functions of the body [1, 2]. Consequently, there is an increasing requirement for advanced materials with enhanced properties to meet new requirements or to replace existing materials. Among these materials, the healing and biomedical properties of hydroxyapatite composite, amorphous calcium phosphate (ACP), amorphous nanosilica material, zirconia etc have generated much attention. However, these materials are traditionally synthesized with the use of toxic or noxious compounds, which may limit their biomedical applications [3]. Moreover, the environmental concern and cost of production seems to overwhelm the benefits associated with the use of these materials. Hence, a new technology and method of synthesizing and modifying the said materials for medical and dental application becomes highly desirable.

3.2 The Science of Mechanochemistry In recent years, mechanochmistry technology has gain sufficient attention amongst researchers and industrialist for the preparation of different composite materials owing to the versatility, energy saving potential, and environmental friendliness of the technology [4, 5]. Besides its simplicity and ease of use, mechanochemical treatment is reported to have positive effect on the properties of composite materials which could be attributed to its functionality. As revealed in literature [3], mechanochemistry harnessed mechanical force to induce chemical reactions or structural changes of material that is similar to those provided by thermochemistry (energy by heat), photochemistry (energy by light) or electrochemistry (energy by electrical potential). Owing to these attributes, mechanochemistry is considered a powerful technique for modulation of chemical reactivity and preparation of materials with high performances [6, 7]. By this mechanical activation, it becomes possible not to only cause structural changes in the material but also reduce their particles sizes [8]. Given the above significant benefits in the use of mechanochemical approaches in the preparation of composite materials, this chapter aim to highlight some recent development and application of mechanochemistry and to call attention the possibilities for future

Mechano-Chemistry in Composite Preparation

59

study. It is interesting to mention that this technology is a rapidly evolving field with several advantageous properties. Nonetheless, it is worth stressing that the science of mechanochemistry is not a recent invention and practice. This technology appeared to have had its application dating back to the Stone Age.

3.3 Brief History of Mechanochemistry Application Although the recognition of mechanochemistry as a distinctive aspect of science was slow in coming, nevertheless, its use in material preparation has had a long history. According to historical document [9], the first recorded use of mechanochemistry principle was attributed to Aristotle’s student Theophrastus of Eresus (ca 315B.C). In his short work entitled “on stones”, Theophrastus described the reduction of cinnabar to mercury by grinding the material in a copper mortar and pestle. Presumably, Theophrastus may have unwittingly apply the process of mechanochemical reaction following the reaction in equation 3.1.

HgS + Cu → Hg + CuS

(3.1)

Despite the work and contribution by Theophrastus, the mechanochemical preparation of materials remain uncharted territory for nearly 2000 years [9]. Still, it is well known that milling operations such as grinding were extensively utilized during this periods to process materials like grains, black powders, building materials, minerals, and pharmaceuticals products. This is more so, as mortar and pestle was the standard laboratory instrument for chemical preparation by the early chemist and Alchemist [9]. And the application of these techniques resulted to chemical effects and changes. Of interest, and moving away from the Aristotle era, Michael Faraday was the first to be accredited with the concept of modern application of mechanochmistry. He has in 1820, reported on the lessening of silver chloride (AgCl) with various active metals (Zn, Sn, Fe, Cu). This he achieved by grinding in a mortar, in a procedure described by him as ‘the dry way’ [10]. Faraday’s report could be considered as the first systematic studies of mechanochemical

60 Composites for Environmental Engineering process. His styles and choice of words suggests that mechanochemical application was well know during his time, although, little literature exist on the topic [9]. The work of Carey Lea an American chemist in 1866, however, inspired the modern concept of the word mechanochemistry. His work largely distinguished the differences between chemical changes induce by thermochemical and that of mechanical reactions [11]. This set outside the assumption that chemical changes observe from grinding process could be due to thermochemical processes. However, it was Wilhelm Ostwald that introduced the term mechanochemistry in 1919 [12]. Ostwald understood mechanochemistry in a wider sense and viewed it as a distinct subdiscipline of chemistry [9]. Heinicke [13] succinctly captured this concept in his widely accepted definition that mechanochemistry is a branch of chemistry which is concerned with chemical and physio-chemical transformations of substances in all states of aggregation produced by the effect of mechanical energy. Despite the exhaustive and extensive history of mechanochemistry, it was until recently; that it was added into the chemical literature. The recent IUPAC Compendium of Chemical Terminology defines mechanochemical reaction as a ‘‘chemical reaction that is induced by mechanical energy’’ [14]. Although the recognition of mechanochmistry in the scientific space could be considered belated, it is, however, exciting to note that the technology presents an opportunity to go beyond the boundary of chemical reaction.

3.4 Mechanochemical Tools Over the last decade, mechanochemical tools have transcendent from its earliest mortar and pestle (Figure 3.1a) to more elaborate and sophisticated electronic devices (Figure 3.1b). Among these new devices, the ball-milling, tumbling mill, planetary mill, mixer, and rolling mill etc. (Figure 3.2) have been extensively utilized as a tool for mechanochemical reaction. Ball-milling is a common comminution method of producing fine powder in many industrial fields. Baláž [4] noted that ball-milling combines solid state approach and mechanical energy input for various desired applications. The

Mechano-Chemistry in Composite Preparation

(a)

61

(b)

Figure 3.1 Showing (a) mortar and pestle; (b) modern planetary ball-milling.

A

D

B

C

E

F

Figure 3.2 Different types of mills for high energy milling: A – ball mill, B – planetary ball mill, C – vibration mill, D – attritor (stirring ball mill), E – pin mill, F – rolling mill (Source [16]).

tumbling mill with centrifugal and planetary action is also been used in the preparation of fine powders from a variety of materials namely: ores, chemicals, glass, ceramics, and plant materials [8]. The tumbling mill is often considered as the progenitor of the planetary ball-mills commonly used today. The planetary ball-milling through the imposition of impact, shear and friction forces has the capability to reduce particles into fine powders [8]. In the planetary ball-milling, it is worth noting that the reagents and ball(s) must be loaded as before and the jars spin counterdirectionally to the spinning disc that they are mounted on [15]. Another type of the ball-milling is the mixer. This devices uses the movement of ball bearings to apply mechanical force to the reagents. Here, reagents are loaded into jars and one or more ball bearings are

62 Composites for Environmental Engineering added. The jars are then mounted horizontally and shaken based on the operator’s desired applications. The above mentioning devices requires high energy mills with different working requirement such as compression, shear, impact etc. It is worth stating here that several variables influences the milling process. As such, the operator must pay keen attention to parameters like the material of the milling media; the type of the mill to use; milling speed and time; ball-to powder ratio, milling atmosphere; as well as the filling extent of the milling chamber [17]. Apart from these, the type of mechanochemical vials or reactors and balls could also contribute to the end results. Table 3.1 highlights the different milling materials and their composition. It is critical to note that the

Table 3.1 Material specification for grinding bowl and balls material. Use for grinding stock

Density in g/cm3

Main components

Agate

Soft to mediumhard samples

2.65

(99.9% SioO2)

Silicon nitride

Abrasive samples, metal-free grinding

3.25

(90% Si3N4)

Sintered corundum

Medium-hard, fibrous samples

3.9

(99.7% A12O3)

Zirconium oxide

Fibrous, abrasive samples

5.7

(96.2% ZrO2)

Hardened, stainless steel

Medium-hard, brittle samples

7.7

(16.0-18.0% Cr)

Tungsten carbide

Hard, abrasive samples

14.9

93% WC + 6% Co)

Materials

Mechano-Chemistry in Composite Preparation

63

use of these devices will depend on the intended applications and materials to be milled. The planetary ball mills by Fritsch company (invented 1961, Germany) are considered as the mainstays of many laboratories using the principles of mechanochemical reaction in their material preparations. The attractiveness of the Fritsch product in the mechanochemical reaction is the durability and automation of the unit. For instance, the operator has the discretion to vary the setting, milling time, and speed to suit his or her desired applications. More so, the Fritsch unit has energy density about 100–1000 times higher when compared against the earliest conventional milling equipment [18]. As such, the unit is quite pricy and is only desirable for processing of larger and harder materials. Alternatively, for the processing of smaller samples, it is recommended to use laboratory shaker, disc and vibration mills etc. The only drawbacks arising from mechanochemistry in research is the challenge of contamination. Ferencz [16] noted that the small size of milled particles, the availability of large surface area and the formation of new surfaces during milling all contribute to the contamination of the powder. Consequently, the author had recommended the use of special materials as components of the vials and grinding balls lowering the Fe contamination of the samples. In addition to these, the use of protective inert atmosphere for moisture or oxygen sensitive materials was also noted to reduce the chances of contamination.

3.5 Applications of Mechano-Chemistry in the Milling of Eggshell Powder Eggshells are bioceramic composite with unique organic and inorganic compounds made mainly of calcium carbonates (~97% by weight) [19]. In recent years, the modification of eggshell waste through ball-milling to obtain a novel material has gained numerous attention amongst researchers owing to their environmental friendliness, less use of harmful organic solvents and energy as well as its reproducibility with high yield under simple and easy operating conditions [4, 5]. Ball-milling natural material such as eggshells offers

64 Composites for Environmental Engineering

Figure 3.3 Eggshell powder in a jar of 10mm balls.

the prospect to change their applications potential to a new level. For the milling of eggshell, it is widely reported [4] that the number of balls ranged from 4 to 50 often with a 10 mm (Figure 3.3) or smaller balls. According to Tsai, Yang [8], the availability of fine eggshell powder in the fields of biomaterials is very much important. Interestingly, mechanochemistry brings about the possibility to prepare nanomaterials by using a top-down approach [17]. Onwubu, Vahed [20] demonstrated that a nanosized eggshell powder prepared through ball-milling process were effective as a dental powder abrasive material (Figure 3.4). Equally important, mechanochemical milling of eggshells have been reported to induce phase transformation in the eggshell carbonate structure from calcite to aragonite and vice versa [21]. This phase changes is, however, milling time dependent. It has been shown that eggshell milled above 250 min causes the transformation of calcite to aragonite or aragonite to calcite [22]. In a more recent study [23], eggshell powder were modified with titanium dioxide (EB@TiO2) through ball-milling both material in a ratio 4:1 at a speed of 400rpm for 200min. The authors observed that ball-milling induce the coating of TiO2 particles on the surface of the eggshell powder without necessary changing the calcite structure of the carbonates in the eggshell. The investigation of the particle size distribution showed no agglomerate in the modified composites (Figure 3.5). The new composite is suggested to have improved acid resistant against tooth erosion.

Mechano-Chemistry in Composite Preparation

(a)

(b)

65

(c)

Figure 3.4 Showing (a) eggshells; (b) ball-milled powder; (c) dental polishing process.

B A

200 nm

Figure 3.5 TEM images of eggshell powder coated TiO2 (A) irregular shaped particles typified eggshell powder; (B) spherical shaped particles typified TiO2.

3.6 Conclusions In summary, the science of mechanochemistry, particularly the modern use of planetary ball milling has made enormous progress in recent decade. Its application in material preparation has altered the traditional dependent on solvents. In particular, when the debate of climate change is considered, the planetary ball milling is highly advantageous in these regards. It offers more simplicity, waste free conditions, and environmental friendliness; which is high in the global agenda of clean environment. In terms of efficiency, the technology influences chemical reaction, homogenization of

66 Composites for Environmental Engineering materials with emphases in creating phase changes in composite material. While the reemergence of mechanochemistry principle has excited many scholars and researchers, it still has a long way to go in terms fully understanding the mechanism of the reactions and the industrial application of the technology. Nonetheless, this chapter has highlighted the advances made so far by bringing to the forefront the benefits of mechanochemical reaction. Hence, it is strongly recommended that mechanochemistry be incorporated in text books, part of course content and chemistry curriculum.

References 1. Ratner, B.D. and Bryant, S.J., Biomaterials: Where we have been and where we are going. Annu. Rev. Biomed. Eng., 6, 41–75, 2004. 2. Badami, V. and Ahuja, B., Biosmart materials: Breaking new ground in dentistry. The Scientific World J., 2014, 1–7, 2014. 3. Hua, Z., Nie, M., Liu, X., Wanga, Q., A Clean Strategy to Prepare Polylactide/Hydroxyapatite Bionanocomposites via Solid Mechanochemistry. J. Macromol. Sci. B: Phys., 56, 5, 306–14, 2017. 4. Baláž, M., Ball milling of eggshell waste as a green and sustainable approach: A review. Adv. Colloid Interface Sci., 256, 256–275, 2018. 5. Baláž, P., Achimovičová, M., Baláž, M., Billik, P., Cherkezova-Zheleva, Z., Criado, J.M. et al., Hallmarks of mechanochemistry: From nanoparticles to technology. Chem. Soc. Rev., 42, 18, 7571–637, 2013. 6. James, S.L., Adams, C.J., Bolm, C., Braga, D., Collier, P., Friscic, T. et al., Mechanochemistry: Opportunities for new and cleaner synthesis. Chem. Soc. Rev., 41, 413–47, 2012. 7. Brantley, J.N., Wiggins, K.M., Bielawski, C.W., Polymer mechanochemistry: The design and study of mechanophores. Polym. Int., 62, 2–12, 2013. 8. Tsai, W.T., Yang, J.M., Hsu, H.C., Lin, C.M., Lin, K.Y., Chiu, C.H., Development and characterization of mesoporosity in eggshell groun by planetary ball milling. Microporous Mesoporous Mater., 111, 379– 86, 2008. 9. Takacs, L., The historical development of mechanochemistry. Chem. Soc. Rev., 42, 7649–59, 2013. 10. Faraday, M., Dry way in inducing reactions. Q. Jl. Sci. Lit. Arts, 8, 374– 75, 1820.

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11. Rightmire, N.R. and Hanusa, T.P., Advances in organometallic synthesis with mechanochemical methods. Dalton Trans., 45, 6, 2352–62, 2016. 12. Ostwald, W., Handbuch der Allgemeinen Chemie, Band 1, Akademische Verlagsgesellschaft mbH, Leipzig, 1919. 13. Heinicke, G., Tribochemistry, Akademie-Verlag, Berlin, 1986. 14. IUPAC Compendium of Chemical Technology, The “Gold Book”, 2nd ed., A.D. McNaught and A. Wilkinson (Eds.), Blackwell Scientific Publications, Oxford, 1997. 15. Howard, J.L., Cao, Q., Browne, D.L., Mechanochemistry as an emerging tool for molecular synthesis: What can it offer? Chem. Sci., 9, 12, 3080–94, 2018. 16. Ferencz, Z., Mechanochemical Preparation and Structural Characterization of Layered Double Hydroxides and their Amino Acid-Intercalated Derivatives: szte, PhD Thesis. University of Szeged: Szeged, 2016. 17. Baláž, P., Mechanochemistry in Nanoscience and Minerals Engineering, Springer-Verlag, Berlin Heidelberg, 2008. 18. Fokina, E., Budim, N., Kochnev, V., Chernik, G., Planetary mills of periodic and continuous action. J. Mater. Sci., 39, 16–17, 5217–21, 2004. 19. Onwubu, S.C., Vahed, A., Singh, S., Kanny, K.M., Physicochemical characterization of a dental eggshell powder abrasive material. J. Appl. Biomater. Func. Mater., 15, 4, e341–e346, 2017. 20. Onwubu, S.C., Vahed, A., Singh, S., Kanny, K.M., Reducing the surface roughness of dental acrylic resins by using an eggshell abrasive material. J. Prosthet. Dent., 117, 2, 310–14, 2017. 21. Baláž, M., Zorkovská, A., Fabián, M., Girman, V., Briančin, J.A.P.T., Eggshell biomaterial: Characterization of nanophase and polymorphs after mechanical activation. Adv. Powder Technol., 26, 1597–608, 2015. 22. Baláž, P., Calka, A., Zorkovska, A., Baláž, M., Processing of eggshell biomaterial by electrical discharge assisted mechanical milling (EDAMM) and high energy milling (HEM) techniques. Mater. Manuf. Processes, 28, 4, 343–47, 2013. 23. Onwubu, S.C., Mdluli, P.S., Singh, S., Evaluating the buffering and acid-resistant properties of eggshell–titanium dioxide composite against erosive acids. J. Appl. Biomater. Func. Mater., 1–7, 2018.

4 Fiber-Reinforced Composites for Environmental Engineering Gayatri T. Nadathur1, Pintu Pandit2* and Kunal Singha2 1

Institute of Chemical Technology, Mumbai, India National Institute of Fashion Technology, Department of Textile Design, Ministry of Textiles, Govt. of India, NIFT Campus, Patna, India

2

Abstract Applications of composite materials are increasingly in demand in the field of environmental engineering with emphasis on effective solutions. Managing the physical and chemical properties to achieve the application goal of the composite material is required for economically cheap and sustainable products. Potential applications for composites lie in the area of pollution control, Sound absorbent, air filters, strong and flexible membranes for water purification in effluent treatment, fire retardancy, oil spill remediation, etc. depending on the chemical nature and processing of the composite. The specific advantages of natural resource based composites, nanomaterial and synthetic fiber based composites, can be managed to fit the end use. Keywords: Composite, natural resources, applications fibers, environmental engineering

4.1 Introduction Environmental engineering involves the deployment of science and engineering knowledge and constructs in the pursuit of maintenance and conservation of the environment, especially in *Corresponding author: [email protected] Shakeel Ahmed and Saif Ali Chaudhry (eds.) Composites for Environmental Engineering, (69–98) © 2019 Scrivener Publishing LLC

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70 Composites for Environmental Engineering its interaction with human activities that signal modern civilisation like building, transport, mining, industrial agriculture, and energy harvesting so that hazards are mitigated, if not resolved, for both the human and environmental components. Wastewater management required in industrial runoffs and urban sanitation, air pollution control for exhaust from automobile emissions and manufacturing plants that process fossil fuels at any step or use them to generate energy, as in coal powered electricity—these are some examples where environmental engineering has significant impact. Fiber reinforced composites (FRC) are increasingly substituting for metal components in automobile bodies, aeroplane and other aerostructures, bringing into focus their most important feature of lightweight construction with strength. Modern jet planes used for transport may contain upto 50-53% of FRC materials. There exist limitless opportunities in their utilization, enabled by the science of material chemistry and composite technology. In  the last half century of development, FRC materials have come to the forefront when replacing 100% metal and ceramic load-bearing structures. The ubiquitous utility poles for power distribution and transmission, as well as last mile telephonic/communication cable connections, are a visible example of the application of these FRC materials, replacing wood and cement poles. The previous materials were subject to insect and avian attack, in case of wood, or the cement poles were simply too unwieldy and heavy relative to the ground geography in which they were to be embedded, like in rocky, mountainous or desert regions, or in high density urban areas. Being easily subject to damage by high winds, or UV damage was another disadvantage. But FRC utility poles made of materials like E-glass fibers and polyester/vinyl ester resins blended with UV inhibitors, in a portable, modular design have tremendous ease of handling, installation and repair in case of damage. Such FRC utility poles are low cost when considered from the lifecycle perspective, as well as in terms of maintenance and reliability, when considering that power supply grids have to be functional in extreme weather conditions bearing heavy ice, snow, rain and storm-force winds. They also have good flexibility, bending 45–50° relative to the ground without breaking, undergoing deformation

Fiber-Reinforced Composites 71 but returning to its original conformation, with minimal fatigue. These poles ranging in length from 30-150 ft. are made by a process of filament winding of resin-impregnated fibers; sections may be assembled for longer lengths, and are non-conductive in nature so that linemen at work are protected. They are light weight, rust free, durable and rugged [1]. Fiber reinforced composites are essentially a combination of polymeric matrix, considered a continuous phase, with reinforcing fibers, as the dispersed phase, to give a synergistic combination of desired properties, inherent to the constituent components. The compressive strength of the matrix adds to the fibers’ tensile strength. The fibers distribute the load applied to the composite block, so that it preserves its shape and structure. The FRC could be strong while its components are independently brittle, based on the fact that multiple fracture energy absorbing pathways are available to the FRC, modulating its fracture toughness. The arrangement of fibers in the matrix could be continuous and aligned in one direction, continuous and aligned in two directions (as in weaves), continuous and randomly oriented (as in a mat) or both discontinuous and random. Sometimes a structural composite is made when layers of fiber composites are stacked in specific orientations to form laminates. This isotropic, anisotropic or orthotropic nature of fiber orientation along with fiber dimensions and density affect the material properties such as mechanical behavior, nature of shrinkage under curing and thermal stability. Commonly used fibers are glass, carbon, or aramid polymers, while the matrix could be thermosetting resins of an epoxy or polyester chemically, or even ceramics and metals. The strengthening effect of the fibers arises when they remove faults present in the matrix, as in brittle spots in ceramics or those formed due to the alignment of the polymer chain in the matrix. Depending on the application performance to be achieved by the composite, the choice of the matrix or fiber can be based on the required merit index E/ρ2 and the related Ashby property plots (Figure 4.1). The failure mechanism of FRC, which is crucial to its behavior when subject to force, is determined by the nature of matrix deformation, fiber fracture, debonding at the fiber-matrix interface, deflection of cracks and degree of fiber pull-out.

72 Composites for Environmental Engineering

Impact strength[kJ m−2]

300 GFRPs CFRPs PFRPs SFRPs

200

Glass-epoxy Carbon-epoxy

Glass-polyseter Silk-epoxy

100 Glass-acrylic Musa-PP Jute-PP

0 0

Glass-PP

Wood-PP Cordenka-PLA Bamboo-ABS Musa-PP Jute-PP Flax-AESO

20 40 60 Fiber volume fraction[%]

Figure 4.1 Comparison of the impact strength at room temperature of polymer composites reinforced by glass fibers (GFRP), carbon fibers (CFRP), plant fibers (PFRP) and silk fibers (SFRP) [2].

4.2 Strength of FRC Materials Matrix deformation can remain insignificant in FRC, without compromising its strength, as fibers distribute load applied, bearing most of the stress; but ductile matrices allow greater deformation, as in a resin in opposition to a brittle ceramic. Ductile matrices can experience plastic deformation before breaking, which uses up some kJ m-2, of the total energy required to fracture, but breaking brittle fibers requires a magnitude less energy. Fiber need not fracture in the same plane as a crack, but depends on the nature of fiber faults and strengths. Breaking a fiber contributes minimally to fracturing a composite, as the interphase, matrix, and remaining fibers remain stable. Toughness of composite arises from the repeated deflection of cracks at the boundary regions between fiber and matrix. The debonding of fiber from the matrix requires less energy but it allows fiber pull-out to occur, so that the destructive energy is absorbed, and the cracks are not propagated (Figures 4.2, 4.3). Fibers could also elongate before breaking, such that they bridge the crack. Fibers affect the nature of failure mechanism and also allow ease of repair after fracture of the whole block [3]. In discontinuous fiber reinforced composites, the length of fiber is exponentially greater than its cross-sectional length, though much

Fiber-Reinforced Composites 73 Hole left by fiber Force Direction Composite Deflecting Crack

Reinforcing Fibers Fiber bridging of crack

Figure 4.2 (a) Fiber pullout during crack growth (b) Crack deflection by reinforcing fibers.

Complete debonding Progressive debonding C

Load P

A’

A

Load drop D

B

E Debond initiation

Fiber pull-out

Displacement δ

Figure 4.3 Load displacement graph of a fiber reinforced composite [4].

shorter than the whole length of the composite piece. Microscopically, in contrast, the continuous fiber reinforced composite has fibers spanning the whole length of the piece, without any break. This difference in fiber composition affects the stress distribution via friction between fiber and matrix, and also fracture development, and resistance to abrasive wear in the respective matrices. Random distribution of aligned fibers gives greater reinforcement than regularly distributed or staggered but uniform distribution of aligned fibers in the matrix. The ability to distribute load from matrix  to

74 Composites for Environmental Engineering fibers depends on their volume fraction. Volume fraction of fibers in turn depends on their packing configuration, in the order hexagonal > square diagonal > square edge, of decreasing volume fraction. The role of short/discontinuous fibers in offering a heterogeneous internal structure of the composite to reinforce against crack progression is crucial. Since thin fibers with cross-sectional diameters of the order of nanometer have fracture strength close to the ideal material values, being mechanically more stable, materials like carbon nanofibers have become important in advanced composites manufacture. They favour greater packing density, and high ratio of surface area to volume, to increase the fiber–matrix coupling across the interface by long range chemical bonding or mechanical interactions [5].

4.3 Composite Manufacturing Composite manufacturing processes such as compression moulding, injection moulding and winding could use reinforcing textile products (nonwovens, fibers, filaments) for production of FRC and allow the modification of composite properties, depending on the nature of the fiber component. The manufacture of composites for automobiles, and transportable storage vessels has driven a lot of developments in composite manufacturing (Figure 4.4). Automobile composites, which possess high strength to weight ratio, have an impact on the environment, contributing to better fuel mileage, and reducing greenhouse gas emissions when fossil fuels power all transport. The production cost of discontinuous FRC could be less than that of continuous FRC, as they contain a lower volume of fiber with respect to the total composite volume. CFRCs can be prepared by layering of fibers arranged in specific directions followed by filling the interfiber space with the matrix polymer. In contrast, the preparation of DFRCs involves blending fibers into the matrix in a molten state, followed by matrix curing to solidify. This could be done by injection of the liquid matrix-fiber blend into a mould, where fibers align in the flow direction. This could involve different processes like Resin Transfer Molding (RTM), Sheet Molding Compound (SMC),

Fiber-Reinforced Composites 75 Miscellaneous, 4% Marine, 12% Automotive, 31%

Electronic, 10%

Aerospace, 1%

Appliances, 8% Construction, 26%

Consumer Goods, 8%

Figure 4.4 Use of FRC in different commercial sectors by market value [6].

Long fiber thermoplastic molding (LFT), and programmable powder preforming process (P4) [7]. In RTM, a catalyst or hardener is mixed with a resin and then injected into a mold containing fiberglass or other fibers as reinforcement. RTM can produce curved panels with surfaces that can be color finished. The RTM composite allows for complex forms and shapes such as compound curves. Strength of RTM panels are greater due to oriented continuous fibers while having the greatest fiber density and weight savings compared to the other discontinuous fiber processes such as SMC, LFT and P4, which also give panels with comparable mechanical properties for similarly stiff structures. The cost per piece produced by these processes are in the increasing order LFTlyocel>PET>nylon [38]. By an optimized choice of fiber, matrix and geometrical configuration of reinforcing fiber, good mechanical performance can be achieved even at a lower cost.

4.7 Liquid (Water or Oil) Filtration Media Filters made from fiber glass reinforced plastic/polyester, which are corrosion resistant, find wide use in commercial brackish, seawater filtration units and in desalination systems. Composite filters provide the benefit of material strength, economy of weight and good mechanical strength, when used in filter systems. The use of glass fiber reinforced plastic pipes and fittings in large diameter filter tank, and high pressure zone pipelines is cheaper to install and maintain than conventional materials. The smooth inner liner of such pipes which are 4 times less in weight in steel, and of lengths of upto 12m of varying diameters, with fewer jointed sections reduce leakage and offer low friction for operational energy savings. They have low defect in use with lifetime lasting half a century or more, while also being completely immune to corrosion, when subjected to cleaning chemicals or those from the fluid in flow. A desalination plant using high pressure salt removal through reverse osmosis installed in Llobregat, Barcelona, was constructed with GRP in the pipes corresponding to the intermediate and low pressure network, while vinyl ester resins where used for the piping and fittings of the pretreatment zones. Such resins were resistant to corrosion by the salt and also the treatment chemicals of sodim hypochlorite, ferric chloride etc., while also having minimal dissolution in the drinking water, within the approved limits. The GRP containing process lines in the desalination plant, used pipes fabricated via a crossed filament winding process, with the vinyl ester adhesives performing as well or better than previously used steel [39]. Composite filters are used to clean water in large volumes at at a water-themed resort in Dubai. Horizontal filters that are

Fiber-Reinforced Composites 87 1.5 m in diameter and 3.7 m in length, have the internal manifold made of PVC. Water is pumped through the filters which can withstand pressures of up to 100 psi. The horizontal, cylindrical housing for the filters are made by winding resin-impregnated glass fiber reinforcement on a rotating mandrel. The bisphenol A epoxy-based vinyl ester resin used for the binding, fulfill requirements for utility in food, water and consumer goods. The FRP was made of both continuous roving for circumference strength and stitched fabric for axial strength. Chopped strand mat and woven roving were used to mould the filter end caps. A surfacing veil of C-fiber glass was used to cover the inner surface of all the pipe and filter parts, providing a smooth surface to resist internal pressure and also corrosion. The vinyl ester resins used do not suffer cracking or crazing during the filtering process, unlike isophthalic polyester resin [40]. A low blend ratio of 2.5% of sulfonated polysulfone (SPSU) as the hydrophilic component in a hydrophobic PVC matrix was used to prepare a thin film composite (TCM) forward osmosis (FO) membrane, which had high performance with low cost input, when polysulfone component is quite expensive. The use of SPSU allowed porosity in the neat PVC matrix, while the active polyamide layer became rough, loose and less crosslinked, in presence of SPSU. The pure water permeability improved by 231.34% from 0.67  LMH/ bar to 2.54 LMH/barn measured at 5.0 bar pressure in the reverse osmosis mode. The reduction in S (structure) parameter from 2668 μm in the neat PVC membrane to the value of 337 μm in the 2.5% SPSU blended TCM pointed to a reduction in the internal concentration polarization barrier developed in the FO membrane [41]. River water of turbidity 34°, when filtered through a ceramic filter made of waste glass fiber reinforced plastic mixed with clay, experienced 70-85% reduction in turbidity. The coefficient of permeability of the filters increased with the composition of the GFRP from 40-60%, and the increase in its particle size from 0.5 mm or less to ranging from 0.5-1.0 mm, to around 0.01 cm/s, and higher [42]. The pleated filter element in oil filter cartridges that filter soot and metal particles from engine lubricants to prevent wear and tear on the engine is a product that could be made of carbon fiber reinforced with thermoplastic resin through wet paper making technology. It is commercially available as CARMIX CFRP.

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4.8 Air Filtration Media Glass fibers are found to be especially suitable for use in Air filters. They have multiple advantages of being chemically inert, thermally stable, non-hygroscopic and do not swell with moisture, with availability in a wide range of diameters to suit the filtration bandwidth required, for particle sizes filtered ranging from micron to submicron. They may be shaped as mats, tubes, webs, membranes of required dimensions, and fit the shape of the filter element providing a large surface area for holding the dirt deposited with a suitable balance of void spaces for the work of filtration. They may be used with binder, with or without curing, or with adhesives as suitable. They are fabricated by blowing molten glass into fiber collected onto a moving belt, which is further mandrel wrapped before curing. Interleafing with auxiliary fiber glass material such as webs, mats and blankets, aid to increase mechanical strength and filter life. Phenol-formaldehyde resins are used to bond the fibrous glass mass at concentrations from 3-5%, with the higher concentration of binder increasing mechanical strength but detracting from dirt holding ability. Adhesive coated filters exhibit greater particle removal, without any extra resistance compared to uncoated filters. Such filters need to be replaced at the end of their lifetime, as greater power is required to blow air through filters at the end of their life, which is more expensive. Filter media are correlated with specific filtrate equipment that maximizes their utilization of particle removal of the target range from pollen, fine dust and bacteria to coarser particles. Glass filters when adapted to liquid filtration have the advantage of no leaching or extractables from the filter media [43].

4.9 Filtration/Separation of Oil-Water Liquid Mixtures Fiber reinforced composites have also found application as effective adsorbents in oil spill cleanup. Silica aerogels that have high surface area, are very porous, lightweight, transparent, hydrophilic and are brittle, are converted by embedding long polyacrylonitrile fibers of 50mm length and 10 μ diameter, during their synthesis, into

Fiber-Reinforced Composites 89 stronger materials with improved mechanical strength. Aerogels with 0.3% fibers recover completely after 40% compression and have a modulus of 260 kPa, and even possess very high porosity. They become superhydrophobic with contact angles as high as 169°, after silylation of the silica hydroxyl groups with trimethylchlorosilane, to give new hydrophobic methylated silica aerogels. Such composites absorb 7.5 times their weight of diesel oil, over repeated cycles of immersion-extrusion by squeezing off, and they float on the oilwater mixture [44]. Thin film composite membranes often used in RO processes are chemically modified and adapted for use in FO processes that consume lower energy and have lower fouling tendency, to recover cleaner water from oily waste water. They are fabricated from layers of different materials that are combined into a single membrane for optimal performance and mechanical strength. A commercially used membrane FILMTEC FT30 contains an outer thin aromatic polyamide barrier layer that allows high water flux, rejects salt and silica, while resisting chemical corrosion. The barrier layer applied by interfacial polymerization, is very thin at 0.2 micron thickness. Beneath this outer layer is a 40 μ thick microporous polysulfone sublayer that acts as a smooth support, offers necessary porosity and strength, resisting compaction under RO pressure conditions. The polysulfone layer is cast onto a nonwoven polyester inner web 120 μ thick that offers structural and mechanical strength. The membrane sheets are glued together with a permeate spacer of polyester fabric 10-16μ thick, to draw water away from membrane rapidly. Numerous such membrane leaves are put together to form a single element. The membrane leaves are separated by a feed brine spacer, a PP netting of 28-34 mm thick, to direct flow. The element is housed in an ABS shell to protect and cover it. An FO process that utilised inorganic salt draw solution of oxalic acid complexed ferric and chromic salts to minimize reverse salt flux, was able to treat 500 ppm oily wastewater with 1.0 M ammonium salt, rejecting 99.5% oil, with minimal solute flux of 0.01 g/L [45]. A double-skinned TFC FO membrane containing a polyacrylonitrile (PAN) porous substrate enclosed by a dense polyamide layer on the upper surface and a lower layer of Nexar sulfonated pentablock copolymer was tested for cleaning performance on 200,000  ppm

90 Composites for Environmental Engineering emulsified oil. On using 0.5 M NaCl draw solution, output water obtained a removal of >99.9% oil along with a promising water flux of 10.9 L/m2·h. The anti-fouling capacity of Nexar copolymer allowed establishment of stable flux even when operated over longer duration [46,47]. Newer membranes prepared using grafting approaches to modify active surface or blending nanomaterials into the substrates, allow higher performance for cleaning oil - containing water. Oil adsorbents sourced from natural renewable materials, in the form of fiber reinforced composites have shown effective performance. Cardanolfurfuraldehyde bioresins prepared through in situ bulk polymerization were reinforced with acetylated curaua fibers. Magnetic nanoparticles were further incorporated into fiber reinforced composite to ease the oil spill cleanup. Acetylation of the curaua fibers increased their hydrophobicity, and hence the oil absorbency by the composites. Resin alone could absorb (10.25±0.35) g/g oil, while composites containing 1, 5 and 9 wt% of the fibers were absorbed (10.93±0.24) g/g, (12.65±0.21) g/g and (12.38±0.18) g/g of petroleum, respectively. 90% of the sorbent could be recovered by filtering and squeezing the oil off, which could be reused further. 9wt% fiber containing composite was able to remove (12.65±0.21) g/g, (11.25±0.56) g/g ad (10.80±0.54) g/g of oil, in consecutive reuse cycles from the water. Oil spill cleanup and recovery system, for use on oil-water mixtures that need to be treated for obtaining potable water, in the form of an FRC has been patented. It is a flat sorbent pad containing an inner core of polyurethane foam covered by a flexible, mechanically strong propylene fabric. Both components are chemically treated to increase their oleophilicity, oil absorbency and water repellence. The outer porous polypropylene fabric attracts oil droplets, and transfer them by capillary action through the PP fibers to the inner PU core, which acts as a storage depot for the adsorbed and absorbed oil, while repelling any water drops, through a function of surface tension and molecular cohesion. Paraffin at 2-20% w/w is coated on the outer PP fabric, to increase hydrophobicity and attract oil drops. The paraffin coating is attached to the sorbent surface by a short oil-modified urethane resin added at 1-10% by weight, to promote wax dispersion, drying of the wax layer, and water repellence.

Fiber-Reinforced Composites 91 Additionally a long oil-modified acrylic urethane resin at 1-10% by weight is used to increase the oleophilicity, flexibility and strength of the coating. The resins are carried in a solvent of mineral spirits at 60-80% by weight, along with naphtha at 10-30% by weight to allow coating at low temperature and ease the drying of the coat. The chemical treatment of the sorbent pad components is done through dipping or spraying, after which excess is removed by a wringer or by passing through rollers. The dried, coated components are stitched together to form the sorbent pad. The sorbent in use floats on water even after selectively absorbing and retaining the oil, and can be reused, after squeezing out the adsorbed oil in a separate container. The oil adsorbed is not contaminated with water, unlike most other oil sorbents, allowing reclamation of the oil. The sorbent capacity is also much higher than conventional sorbents [48].

4.10 FRCs for Noise Reduction NASA, a significant developer of the aerospace industry, has demonstrated the performance of acoustic damping to achieve engine noise reduction using composite parts made by FDM printing of polyetherimide (PEI) polymers reinforced with chopped carbon fibers in a one-step manufacturing process [11]. This does not require the additional steps of bonding and drilling used in the previous manufacturing process. The 3D printed honeycomb structure could be of any unusual shape as required and they held up well in wind tunnel tests, with equivalent results to the conventional honeycombs/ facesheets liners. Noise reduction was achieved in the specified frequency band, with the solid lighter weight parts. Recycled non-wovens recovered from waste material discarded by non-woven manufacturing factories have been converted to noise absorbing textiles. Needle punched polyester non-woven fabrics with greater area density had lower air permeability and hence better sound insulation. The porous structure of the non-wovens provides a tortuous path for sound dissipation. They could be used in interior lining of theatres, auditoriums and even automobile structures [49]. The commercial market has many products offering sound barriers and noise reducers that are made of composites in sandwich

92 Composites for Environmental Engineering structures made from polyester, glass fiber, cotton fibers, polyurethane, and polypropylene free of harmful VOCs like formaldehyde. Non-wovens derived from natural fibers of jute, ramie, coir, cellulose, flax had better sound absorbing properties than even synthetic fibers. The hollow structure of plant fibers plays a crucial role in sound dissipation. A study on the comparison of flax fiber-fabric-reinforced epoxy composite with sandwich structures prepared similarly from Glass-PET, and Flax-PET, for sound absorbing behavior in the frequency range 250-4000 Hz, demonstrated that the flax fiber based structures had much greater sound absorption at at wider frequency range than the glass fiber based material. The sound absorption coefficient (SAC) for the flax fiber based material reached a maximum of 0.96 at 3200 Hz, that is almost complete absorption, while the glass fiber based material had an SAC of only 0.56 in the test range with the maximum lying beyond 4000Hz [50].

4.11 Fire Resistant FRCs High performance thermoplastic composites such as carbon fiber‐ reinforced polyether ether ketone (PEEK) or polyphenylene sulfide (PPS) have been considered suitable substitutes for aerospace metallic parts for efficient use of fuel energy. These materials are mechanically strong, rigid, chemically non-reactive, non‐flammable, lightweight, and retain their properties under harsh environmental conditions, especially at high temperatures (up to 400°C) [11]. Common composites made of non-saturated polyester resins or epoxide resins collapse due to melting at low temperatures of 100°C. Polymer matrices that withstand higher temperatures are more expensive and may not be suitable for continuous production through technologies like pultrusion. One alternative that has been developed from inorganic polymers consists of glass-ceramic matrix composites reinforced with silicon carbide or carbon fibers. They are amenable to processing at low temperatures, cured in autoclave at temperature less than 180°C, at pressures lower than 9 bar, and subject to standard tooling with graphite/epoxy tools or those coated with aluminum, similar to carbon fiber reinforced plastics. They however require a post cure cycle at higher temperature to stabilize the glass ceramic matrix. But they are

Fiber-Reinforced Composites 93 especially mechanically strong, and heat resistant upto 1000°C. They may be used in heat shields, exhaust ducts, pipes for hot fluids or gases and fire barriers. They have a very low coefficient of thermal expansion, and may be used in exhaust components of automobile engines, liners and coatings of boilers and reaction vessels in the chemical industry as they can withstand long use at temperatures between 500659°C, Another approach to develop fire retardant composites is seen in Carbon fiber reinforced bioepoxy composites prepared from commercial sorbitol polyglycidyl ether (SPE) cured with cycloaliphatic amine hardener. The addition of phosphorus based flame retardants like resorcinol bis(diphenyl phosphate) (RDP), ammonium polyphosphate (APP), and their combinations gave a higher LOI value of 33 V/V% for 3% P addition as APP compared to 27 V/V% for 3% P addition through RDP. The combination of 2% P addition through RDP with 1% P with APP, gave the best e fire performance with 32 V/V% limiting oxygen index (LOI), and V-1 UL-94 rate for flame spread. In formulations containing both FRs, RDP, functions in gas phase, balancing solid-phase mechanism of APP, counteracting the plasticizing (storage modulus and glass transition temperature decreasing) effect of RDP in combined formulations [51]. The fire safety of FRC that need to replace metallic components can be managed in this manner. The importance of heat resistant resins that also retard the spread of flame, smoke and poisonous fumes, cannot be gainsaid in the preparation of FRCs that can withstand exposure to high temperature, finding in use cladding, process piping, scrubbers, and cooling towers. In the construction of fire-resistant FRP building panels, halogenated systems tend to be more efficient than aluminium trihydrate (ATH) filled resins delivering a low flame spread index in horizontal fire tests like the ASTM E84 surface burning test. But Halogenated resin systems cannot achieve the desired smoke index value (450 or less) unless the composite panel possess a high glass content and a thickness less than 0.1 inches. Non-halogenated FR (fire retardant) epoxy resins that produce less smoke are now available commercially, which can be used in challenging applications such as electrical laminates. FRP panels need to undergo FR tests, in the actual configuration they are to be used, to give valid estimations. Phenolic resins fulfil strict flame/smoke/ toxicity specifications and do not need specialty fillers. Benzoxazine

94 Composites for Environmental Engineering thermoset resins have good flammability resistance with superlative thermal and mechanical properties. Epoxy novolac vinyl esters can bear higher temperatures than many other resins polymer categories for flame and smoke-inhibiting resins like vinyl esters (including brominated epoxy vinyl ester) and polyesters (including brominated polyesters). However modified acrylics (non-brominated) can usefully substitute for brominated resins, which have the disadvantage of generating toxic smoke while limiting the spread of fire. Commercial choices exist like Advalite , a vinyl hybrid resin made without styrene or other VOC releasing materials. Advalite can withstand temperatures up to 300 F, has a shelf life of 1 year when stored at ambient temperature and requires no post cure, and has been used in car interiors [52].

4.12 Conclusions Fiber-reinforced composites made from synthetic fibers or from natural fibers using petroleum based resins or bio-based resins, are rapidly replacing traditional materials like steel and aluminum, not only as structural, weight-bearing parts, but also in functionally active parts, like power transmission couplings. Being lightweight materials, fiber reinforced composites help overcome the manufacturing barriers of rising petroleum costs, and stricter environmental regulations. Even carbon fibers are finding substitutes in fibers based on basalt mixed with aluminum for cost savings, and weight minimization. The practice of environmental engineering in modern civilization, finds effective solutions in the use of fiber reinforced composites, in wide-ranging applications, some of which, the review above has considered.

References 1. Mazumdar, S., Composites manufacturing: Materials, product, and process engineering, CRC Press, London, 2001. 2. Yang, K., Wu, S., Guan, J., Shao, Z., Ritchie, R.O., Enhancing the Mechanical Toughness of Epoxy-Resin Composites Using Natural Silk Reinforcements. Sci. Rep., 7, 11939, 2017.

Fiber-Reinforced Composites 95 3. Visser, H.J., Brandt, P.D., De Wet, F.A., Fracture behavior patterns of cusp-replacing fiber strengthened composite restorations. South African Dent. J., 70, 390–395, 2015. 4. Bheemreddy, V., Chandrashekhara, K., Dharani, L.R., Hilmas, G.E., Modeling of fiber pull-out in continuous fiber reinforced ceramic composites using finite element method and artificial neural networks. Comput. Mater. Sci., 79, 663–673, 2013. 5. Goh, K.L., Discontinuous-fiber reinforced composites: Fundamentals of stress transfer and fracture mechanics, Springer - Verlag, London, 2016. 6. Żyjewski, A., Chróścielewski, J., Pyrzowski, Ł., The use of fiberreinforced polymers (FRP) in bridges as a favourable solution for the environment, in: E3S Web Conf., EDP Sciences, p. 102, 2017. 7. Vaidya, U., Composites for automotive, truck and mass transit: Materials, design, manufacturing, DEStech Publications, Inc, Lancaster, Pennsylvania, U.S.A., 2011. 8. Njuguna, J., Lightweight composite structures in transport: Design, manufacturing, analysis and performance, Woodhead Publishing, Cambridge, MA, USA, 2016. 9. Duflou, J.R., Deng, Y., Van Acker, K., Dewulf, W., Do fiber-reinforced polymer composites provide environmentally benign alternatives? A life-cycle-assessment-based study. Mrs Bull., 37, 374–382, 2012. 10. Gu, G.X., Su, I., Sharma, S., Voros, J.L., Qin, Z., Buehler, M.J., Threedimensional-printing of bio-inspired composites. J. Biomech. Eng., 138, 21006, 2016. 11. Dermanaki Farahani, R. and Dubé, M., Printing polymer nanocomposites and composites in three dimensions. Adv. Eng. Mater., 20, 1700539, 2018. 12. Love, L.J., Kunc, V., Rios, O., Duty, C.E., Elliott, A.M., Post, B.K., Smith, R.J., Blue, C.A., The importance of carbon fiber to polymer additive manufacturing. J. Mater. Res., 29, 1893–1898, 2014. 13. Ahmed, M., Islam, M., Vanhoose, J., Rahman, M., Comparisons of Elasticity Moduli of Different Specimens Made Through Three Dimensional Printing. 3D Print. Addit. Manuf., 4, 105–109, 2017. 14. Compton, B.G. and Lewis, J.A., 3D-printing of lightweight cellular composites. Adv. Mater., 26, 5930–5935, 2014. 15. Stoof, D., Pickering, K., Zhang, Y., Fused deposition modelling of natural fiber/polylactic acid composites. J. Compos. Sci., 1, 8, 2017. 16. Atagür, M. and Seydibeyoğlu, M.Ö., The use of biotechnology for green composites, in: Fiber Technol. Fiber-Reinforced Compos, pp. 237– 250, Elsevier, Cambridge, MA , USA, 2017.

96 Composites for Environmental Engineering 17. La Mantia, F.P. and Morreale, M., Green composites: A brief review. Compos. Part A Appl. Sci. Manuf., 42, 579–588, 2011. 18. Patel, S.H., Gonsalves, K.E., Stivala, S.S., Reich, L., Trivedi, D.H., Alternative procedures for the recycling of sheet molding compounds. Adv. Polym. Technol. J. Polym. Process. Inst., 12, 35–45, 1993. 19. Steenkamer, D.A. and Sullivan, J.L., Recycled content in polymer matrix composites through the use of A-glass fibers. Polym. Compos., 18, 300–312, 1997. 20. Pickering, S.J., Kelly, R.M., Kennerley, J.R., Rudd, C.D., Fenwick, N.J., A fluidised-bed process for the recovery of glass fibers from scrap thermoset composites. Compos. Sci. Technol., 60, 509–523, 2000. 21. Corbière-Nicollier, T., Laban, B.G., Lundquist, L., Leterrier, Y., Månson, J.-A., Jolliet, O., Life cycle assessment of biofibers replacing glass fibers as reinforcement in plastics. Resour. Conserv. Recycl., 33, 267–287, 2001. 22. Maia, M.F. and Moore, S.J., Plant-based insect repellents: A review of their efficacy, development and testing. Malar. J., 10, S11, 2011. 23. Fortea-Verdejo, M., Bumbaris, E., Burgstaller, C., Bismarck, A., Lee, K.-Y., Plant fiber-reinforced polymers: Where do we stand in terms of tensile properties? Int. Mater. Rev., 62, 8, 441–464, 2017. 24. Shah, D.U., Schubel, P.J., Licence, P., Clifford, M.J., Determining the minimum, critical and maximum fiber content for twisted yarn reinforced plant fiber composites. Compos. Sci. Technol., 72, 1909–1917, 2012. 25. Jadhav, A.C., Pandit, P., Gayatri, T.N., Chavan, P.P., Jadhav, N.C., Production of Green Composites from Various Sustainable Raw Materials, in: Green Compos., pp. 1–24, Springer Nature, Singapore, 2019. 26. Prasad, V., Joseph, M.A., Sekar, K., Ali, M., Development Of Flax Fiber Reinforced Epoxy Composite With Nano Tio 2 Addition Into Matrix To Enhance Mechanical Properties. Mater. Today Proc., 5, 11569–11575, 2018. 27. Dinh Vu, N., Thi Tran, H., Duy Nguyen, T., Characterization of Polypropylene Green Composites Reinforced by Cellulose Fibers Extracted from Rice Straw. Int. J. Polym. Sci., 2018, 1–10, 2018. 28. Rasyid, M.F.A., Salim, M.S., Akil, H.M., Ishak, Z.A.M., Flammability and thermal properties studies of nonwoven flax reinforced acrylic based polyester composites, in: AIP Conf. Proc, p. 30010, AIP Publishing, Melville, NY, USA, 2017. 29. Teli, M.D. and Pandit, P., Novel method of ecofriendly single bath dyeing and functional finishing of wool protein with coconut shell extract biomolecules. ACS Sustain. Chem. Eng., 5, 8323–8333, 2017.

Fiber-Reinforced Composites 97 30. Teli, M.D. and Pandit, P., Development of thermally stable and hygienic colored cotton fabric made by treatment with natural coconut shell extract. J. Ind. Text., 48, 1, 87–118, 2017. 31. Teli, M.D. and Pandit, P., Multifunctionalised silk using Delonix regia stem shell waste. Fibers Polym., 18, 1679–1690, 2017. 32. Sypaseuth, F.D., Gallo, E., Çiftci, S., Schartel, B., Polylactic acid biocomposites: Approaches to a completely green flame retarded polymer. E-Polymers, 17, 449–462, 2017. 33. County, D., Sustainable Design and Building Standards, Dakota County Projects, UK, 2000. 34. Saiter, J.M., Dobircau, L., Leblanc, N., Are 100% green composites and green thermoplastics the new materials for the future? Int. J. Polym. Sci., 2012, 1–7, 2012. 35. Rahman, M.M. and Netravali, A.N., Green resin from forestry waste residue “Karanja (pongamia pinnata) seed cake” for biobased composite structures. ACS Sustain. Chem. Eng., 2, 2318–2328, 2014. 36. Pozo Morales, A., Güemes, A., Fernandez-Lopez, A., Carcelen Valero, V., De La Rosa Llano, S., Bamboo–Polylactic Acid (PLA) Composite Material for Structural Applications. Mater. (Basel), 10, 1286, 2017. 37. Jaisi, D.P., Saleh, N.B., Blake, R.E., Elimelech, M., Transport of singlewalled carbon nanotubes in porous media: Filtration mechanisms and reversibility. Environ. Sci. Technol., 42, 8317–8323, 2008. 38. Tausif, M., O’Haire, T., Pliakas, A., Goswami, P., Russell, S.J., Engineering the mechanical properties of nonwoven reinforced flexible composites, in: Leeds, 2016. 39. van Haaren, K., Opportunities for composites in water desalination. Reinf. Plast., 54, 38–40, 2010. 40. Tisch, J. and Weber, K., Citizen you: Doing your part to change the world. Crown, 154, 240–245, 2010. 41. Zheng, K., Zhou, S., Zhou, X., A low-cost and high-performance thinfilm composite forward osmosis membrane based on an SPSU/PVC substrate. Sci. Rep., 8, 10022, 2018. 42. Yasui, K., Goto, S., Kinoshita, H., Kamiunten, S., Yuji, T., Okamura, Y., Mungkung, N., Sezaki, M., Ceramic waste glass fiber-reinforced plastic-containing filtering materials for turbid water treatment. Environ. Earth Sci., 75, 1135, 2016. 43. S.R. Ellebracht, Dishwasher-dining table having rotatable tabletop, U.S. Patent 9,402,525, issued August 2, 2016. 44. Shi, M., Tang, C., Yang, X., Zhou, J., Jia, F., Han, Y., Li, Z., Superhydrophobic silica aerogels reinforced with polyacrylonitrile fibers for adsorbing oil from water and oil mixtures. RSC Adv., 7, 4039–4045, 2017.

98 Composites for Environmental Engineering 45. Ge, Q., Amy, G.L., Chung, T.-S., Forward osmosis for oily wastewater reclamation: Multi-charged oxalic acid complexes as draw solutes. Water Res., 122, 580–590, 2017. 46. Duong, P.H.H., Chung, T.-S., Wei, S., Irish, L., Highly permeable double-skinned forward osmosis membranes for anti-fouling in the emulsified oil–water separation process. Environ. Sci. Technol., 48, 4537–4545, 2014. 47. Ahmad, N., Goh, P., Abdul Karim, Z., Ismail, A., Thin Film Composite Membrane for Oily Waste Water Treatment: Recent Advances and Challenges. Membranes (Basel), 8, 86, 2018. 48. Bhardwaj, N. and Bhaskarwar, A.N., A review on sorbent devices for oil-spill control. Environ. Pollut., 243, Part B, 1758–1771, 2018. 49. Kalebek, N.A., Sound absorbing polyester recycled nonwovens for the automotive industry. Fibers Text. East. Eur., 1, 115, 107–113, 2016. 50. Zhang, J., Shen, Y., Jiang, B., Li, Y., Sound Absorption Characterization of Natural Materials and Sandwich Structure Composites. Aerospace, 5, 75, 2018. 51. Toldy, A., Niedermann, P., Pomázi, Á., Marosi, G., Szolnoki, B., Flame retardancy of carbon fiber reinforced sorbitol based bioepoxy composites with phosphorus-containing additives. Mater. (Basel), 10, 467, 2017. 52. Parnas, R.S., Flynn, K.M., Dal-Favero, M.E., A permeability database for composites manufacturing. Polym. Compos., 18, 623–633, 1997.

5 Polymer Nanocomposites: Alternative to Reduce Environmental Impact of NonBiodegradable Food Packaging Materials Shiji Mathew and E.K. Radhakrishnan* School of Biosciences, Mahatma Gandhi University, Kottayam, India

Abstract Food packaging is considered as one of the most crucial elements in food industry, as it acts as a physical barrier and aids in food protection and preservation. Non-biodegradable petroleum derived polymeric materials are commonly used for this purpose, which there by impose huge environmental and economic concern regarding their generation, accumulation and disposal. Integration of nanotechnology with materials science has resulted in the ‘Nanocomposite technology’ for engineering of polymers to develop the polymer nanocomposites. Polymer nanocomposites developed from biodegradable and sustainable natural polymers with much improved properties are considered as a better alternative to reduce the ‘white pollution’. This chapter discusses about the development, characterization, properties and food packaging applications of biodegradable polymer nanocomposites. Keywords: Biodegradation, biopolymers, bionanocomposites, food packaging, environmental impact, plastic waste, nanofillers, nanotechnology

5.1 Introduction Food packaging is intended for the containment and preservation of food during its transport, storage, display, to protect the food from *Corresponding author: [email protected] Shakeel Ahmed and Saif Ali Chaudhry (eds.) Composites for Environmental Engineering, (99–134) © 2019 Scrivener Publishing LLC

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microbial spoilage and to extend the shelf life of the product [1]. Plastic has replaced papers, cardboards, glasses and metals for the packaging of wide range of products such as cosmetics, pharmaceuticals, chemicals and foods because of their good material property and low cost [2]. Data suggest that plastics for packaging purpose contributes to the highest share in the global market accounting for 42% [3]. As food is the most frequently utilised commodity in the universe, the plastics used for packing foods contribute the highest share in this industry. Plastics used for the food packaging purpose are generally single use materials which are intended to be disposed immediately after use in an environmentally responsible manner. The most common polymeric materials employed for packaging purpose include non-renewable petroleum resources which are non-biodegradable. These plastics thus get accumulated in the disposal area instead of getting decomposed and contribute majorly to the municipal solid waste. According to Geyer et al., the environmental concern generated by the overproduced plastics is of great alarm. Out of the 6300 million metric tons (Mt) of the global plastic waste generated in 2015, only a small portion was recycled (9%) and incinerated (12%), the remaining 79% has been send to the landfills and discarded in the natural environment. According to the study, if this rate of plastic production and waste management system continues, then by 2050, around 12,000 Mt of plastic waste may be in the landfills, creating serious environmental issues [4]. The accumulation and environmental persistence of plastic wastes in the land and water create immense challenges to waste management and recycling and hence is under strict scrutiny [5]. Currently intense research is underway to find alternatives for petroleum products and to reduce the environmental hazards caused by non-biodegradable plastics. One of the promising approaches to this problem is the use of bioplastics or biopolymers derived from natural resources for packaging purpose. These biopolymers being degradable, is expected to lessen the burden of plastic waste in the environment. Despite the varied advantages over conventional packaging, bioplastics possess inherent lower strength and stiffness. Also, most of the naturally available materials are highly sensitive to water, which is not appropriate for an ideal packaging material. This can result in poor mechanical and

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water barrier properties, thus limiting its packaging applications. Hence, there is a pressing demand on developing sustainable and biodegradable polymeric materials which can reduce the quantity of plastic waste discarded in landfills as well as possess essential functionalities comparable to conventional plastics. Many techniques have been practised for developing biodegradable polymer-based packaging materials with improved mechanical and barrier properties. These include blending of bio-based polymers with plasticisers to improve its brittle nature, chemical modification of biopolymers, blending with other biodegradable polymer to generate hybrid materials with intermediate properties and also use of compatibilizers to make incompatible polymers miscible by maintaining polymer stability [6]. A recent evolution of nanotechnology named as polymer nanocomposites represents a promising option to improve the mechanical and barrier properties of biopolymers. Polymer nanocomposites are prepared by incorporation of particles of nano (10–9) range into the polymer matrices. The nanoparticles due to their increased aspect ratio and high surface area exhibit unique features resulting in improved properties to the resultant product. Many organic and inorganic nanometric materials such as metal and metal oxide nanoparticles and nanoclays find immense application as fillers for improving polymer properties. The reinforcement of nanofillers in biopolymer-based nanocomposites is called bionanocomposites and are found to be better alternative to conventional packaging polymers as they possess excellent mechanical and barrier properties along with being sustainable, biocompatible and moreover biodegradable. This chapter discusses mainly on the advantages of biopolymers over conventional packaging materials together with a brief review on the properties, preparation and characterization of biopolymer-based nanocomposites as promising alternatives to conventional nondegradable plastics.

5.2 Role of Food Packaging Materials Packaging serves an important role in protecting food against external barriers and microbial contamination from processing

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till usage by consumer. Packaging also enables effective distribution of food and facilitates the end-use convenience and communication at consumer levels [7]. Depending on the food type, the commonly used packaging materials include paper, cardboard paper, plastics, glass and a combination of different metals. Since the twentieth century, petroleum-based polymers have been widely used as packaging materials because of their excellent advantages over other materials such as functionality, high durability and ductility, good physio-chemical properties, lightweight, cheap availability and ease of processing [8,9]. The focus of an ideal packaging material is to contain food in a wholesome manner satisfying all industrial requirements with less environmental impact [2]. The commonly used petroleum-based synthetic polymers which provide maximum mechanical stability with poor barrier behavior [3,4] include polyethylene (PE), polypropylene (PP), polystyrene (PS), poly (vinyl) chloride (PVC), polyethylene terephthalate (PET) and polyamides (PA). In spite of the enormous versatility of these polymers, materials are highly permeable to gases and vapor and are nonbiodegradable. Hence, there is a great search for biodegradable polymers made of natural resource which can replace the use of nonbiodegradable plastics in food packaging industry.

5.3 Environmental Impact of Food Packaging The urbanisation and increased reliance on processed foods make food packaging to be one of the highly demanded material and this industry is estimated to contribute 2% of Gross National Product (GNP) in developed countries and is the third largest industry in the world [10]. As more and more inventions and advancements occur in packaging industry, the more it contributes to the environmental impact. Consequently, plastic food packaging materials contributes the major problematic part of solid waste management worldwide [11]. The continuation of the current increased trend in food packaging usage and the prevailing insufficient waste management systems can ultimately result in accumulation of plastic wastes in the landfills and water

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resources, thereby causing huge detrimental effect in the environment. Nanocomposite technology has created huge influence in shaping of the environmental engineering and science. Globally there is a serious emphasis on environment remediation strategies and the great concern prevailing on the plastic waste accumulation in nature has directed the focus of researchers towards the development and use of environment friendly and sustainable green biocomposite materials [12].

5.4 Polymer Nanocomposites The remarkable advancements in material science and technology has brought forward many inventions in hybrid materials called composites. Composite materials, according to International Organization for Standardization, are solid materials formed by the combination of two or more materials with different physical and chemical properties. In the essence, composites are actually two or more materials interacting with close contact and are composed of multiple phases. One phase will be continuous, called the matrix and the other will be discontinuous called the dispersed phase comprising of the reinforced material (fillers such as fibers, platelets, particles, clays) [8]. Combination of different phases can be attained by mixing, blending, compounding, filling, assembling and melting [13]. Nanotechnology has created a breakthrough in composite materials. The development of polymer nanocomposite is an interdisciplinary research area and it enables more benefits to polymers for varied applications [13]. Nanocomposite is defined as a two-phase material where the continuous phase consists of a dispersed phase at nanometer (10–9 m) level. Nanocomposite eliminates the limitations seen with traditional microfillers and also the loading level is comparatively low (