New Industrial Polymers 9780841202290, 9780841201705, 0-8412-0229-X

Table of contents :
Title Page......Page 1
Half Title Page......Page 3
Copyright......Page 4
ACS Symposium Series......Page 5
FOREWORD......Page 6
PdftkEmptyString......Page 0
PREFACE......Page 7
Preparation and Structure......Page 9
Properties......Page 10
Melt Processing......Page 17
Compounding Ingredients......Page 19
Literature Cited......Page 21
INTRODUCTION......Page 23
Structure of 1-, 2-polybutadiene......Page 24
Physical Properties......Page 26
Chemical Properties......Page 27
ACKNOWLEDGEMENTS......Page 32
REFERENCE......Page 33
INTRODUCTION......Page 34
APPLICATION TO EVA SPONGE FIELD......Page 35
APPLICATION TO PHOTO-SENSITIVE POLYMER FIELD......Page 38
CONCLUSION......Page 43
REFERENCE......Page 44
General Properties......Page 45
Processability......Page 53
Literature Cited......Page 56
Abstract......Page 57
Polymer Synthesis and Characterization......Page 63
Physical Testing......Page 64
Results and Discussion......Page 66
Conclusions......Page 69
Literature Cited......Page 70
Introduction......Page 71
Synthetic Procedures for Making Polyarylsulphones......Page 72
Effect of Structure......Page 74
Mechanical Properties......Page 77
Environmental Properties......Page 80
Electrical Properties......Page 82
Processing Properties......Page 84
Applications for Polyethersulphone......Page 86
Conclusion......Page 89
Literature Cited......Page 90
Synthesis and Structure......Page 91
Properties......Page 92
Coatings......Page 98
Injection Molding......Page 100
Applications......Page 101
Literature Cited......Page 106
The Structures......Page 108
The Processing Dilemma......Page 110
The State of the Art......Page 111
Properties and Applications......Page 115
Literature Cited......Page 119
1. Introduction......Page 120
2. Polyaminobismaleimide Chemistry......Page 121
3. Polyaminobismaleimide Properties......Page 126
5. Summary......Page 131
1. Introduction......Page 132
2. PABM Resin......Page 133
3. Structural KINELS......Page 135
4. Self-Lubricating KINELS......Page 145
5. Summary......Page 150
6. Acknowledgments......Page 152
Introduction......Page 153
Results and Discussion......Page 154
Conclusions......Page 162
Literature Cited......Page 163
12 Poly(p-Oxybenzoyl Systems): Homopolymer for Coatings; Copolymers for Compression and Injection Molding......Page 164
References:......Page 170
Plastics without Petroleum......Page 171
Plastics without Petroleum......Page 174
Literature Cited......Page 175
Coal—"New" Source for Plastics......Page 176
Renewable Resources and Solar Energy Conversion Systems......Page 178
Furfural and Furfuryl Alcohol......Page 179
Development of Pullulan: Its Characteristics and Applications......Page 180
2. Plastics......Page 181
6. Foods......Page 182
H......Page 184
P......Page 185
X......Page 186

Citation preview

New Industrial Polymers

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

New Industrial Polymers Rudolph D. Deanin, Editor

A symposium sponsored by the Division of Organic Coatings and Plastics Chemistry at the 167th Meeting of the American Chemical Society, Los Angeles, Calif., April 1-2,

1974.

4

ACS SYMPOSIUM SERIES

AMERICAN

CHEMICAL

SOCIETY

WASHINGTON, D. C. 1972

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

Library of Congress Π Ε Data New industrial polymers. ( ACS symposium series; 4 ) Includes bibliographical references and index. 1. Plastics—Congresses. 2. Polymers and polymeriza­ tion—Congresses. I. Deanin, Rudolph D . , ed. II. American Chemical Society. Division of Organic Coatings and Plastics Chem­ istry. III. Series: American Chemical Society. ACS symposium series; 4. TP1105.N47 ISBN 0-8412-0229-X

668.4 74-26794 ACSMC8 4 1-179 (1974)

Copyright © 1974 American Chemical Society A l l Rights Reserved PRINTED I N T H E UNITED STATES O F AMERICA

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

ACS Symposium Series Robert F. Gould, Series Editor

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

FOREWORD The A C S S Y M P O S I U

a medium for publishing symposia quickly in book form. The format of the SERIES parallels that of its predecessor, A D V A N C E S IN C H E M I S T R Y SERIES, except that in order to save time the papers are not typeset but are reproduced as they are submitted by the authors in camera-ready form. As a further means of saving time, the papers are not edited or reviewed except by the symposium chairman, who becomes editor of the book.

Papers published in the A C S S Y M P O S I U M

SERIES

are original contributions not published elsewhere in whole or major part and include reports of research as well as reviews since symposia may embrace both types of presentation.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

PREFACE •plasties production in the United States is currently growing at an A

average rate of about 12%

pounds by 1980.

per year and may well reach 60 billion

While the major growth is i n the commodity thermo-

plastics, the number of families of commercial plastics is also increasing at a rapid rate. T h e rapid growth o tages they offer over olde processability, flexibility, strength/weight

ratio, impact strength, range

from lubricity to adhesion, abrasion resistance, energy absorption, thermal and electrical insulation, range of color and clarity, resistance to inorganic chemical corrosion, novelty, and economics. A t the same time, there is a continual desire to increase their scope still further by additional improvement in their processability, rigidity, strength, toughness, scratch and mar resistance, thermal expansion, low and high temperature capabilities, weathering, chemical resistance, permeability, and economics. This accounts for the continual development of new plastics materials. After commercial introduction, a new plastic often takes 10-20 years to find optimum major applications and markets. This time can be shortened greatly by improving communication between the developers of new plastics and their potential users in a great variety of industries. T h e purpose of this symposium was primarily to improve this communication. For this purpose, 11 authors from eight companies have contributed 12 papers on 10 new industrial polymer families, and these are collected here.

They present considerable detail on the chemistry,

processing,

properties, and suggested applications of these new materials and should contribute greatly to their more rapid utilization by industry. While the symposium was being organized, a new major challenge suddenly developed in the plastics industry—the growing scarcity, cost, and political uncertainty of petroleum and natural gas as raw materials. T o meet this challenge, the scope of the symposium was broadened by the addition of an impromptu round-table discussion on "Plastics without Petroleum."

The spontaneous audience participation in this discussion

was a reaffirmation of the health, ingenuity, and aggressiveness that have always marked the polymer industries. T h e round-table discussion was collected and organized and is included as the final chapter of this volume. ix In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

Hopefully it will help the polymer industries to begin a major effort to broaden their raw material base and thus ensure their continued healthy growth and service to our modern civilization. RUDOLPH D. DEANIN

Lowell, Mass. October 4,

1974

x In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

1 Radial Block Thermoplastic Rubbers J. R. HAWS Phillips Petroleum Co., Chemicals and Polymers R&D Division, Bartlesville, Okla.

Introduction Butadiene and styrene have been combined i n rubbery polymers in numerous ways to produce a wide variety of properties. Random copolymers made i n emulsion systems have accounted for a large portion of total synthetic rubber; however, modifications i n these are mainly due to changes i n butadiene-styrene ratio and molecular weight with other variations also contributed by changes i n i n i t i a t o r systems, polymerization temperature, modifiers, and finishing methods. In recent years, polymers have been produced i n solution polymerization systems which allow much more latitude i n control of microstructure, molecular configuration, and molecular weight distribution. One result of solution polymerization technology i s the preparation of block polymers - both those that are essentially "pure" block and those that contain some mixtures of block and random structures (1, 2, 3). I t was found that copolymers with styrene blocks on the ends of the polymer molecule provide strong, elastomeric materials without vulcanization. This behavior has been broadly documented (2, 4, 5, 6) and polymers of this type are still under intensive study. Preparation and Structure Block polymers of dienes and styrene are usually prepared in solution polymerization systems using alkylmetal i n i t i a t o r s although exact methods of producing commercial polymers are not often disclosed. Block structures can be formed by sequential addition of different monomers combined with coupling of polymer chains i f desired. Possible synthesis methods have been described i n a number of publications (6, 7) •

1 In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

2

NEW

INDUSTRIAL

POLYMERS

Several structural arrangements of butadiene-styrene copolymers are l i s t e d i n Figure 1 . As indicated, polymers with multiple blocks can be structured i n several ways. Che important distinction that can be made i s between linear polymers and radial, branched polymers. Structures of these are further i l l u s t r a t e d i n Figure 2; Figure 3 demonstrates aggregations of several molecules of simple, linear and radial block polymers. At f i r s t glance, the l a t t e r may not appear too dissimilar, but seme unique properties arise i n the relationships between flow characteristics, structure and molecular weight of these polymers. Properties Consider f i r s t the effects of linear, trichain and tetrachain polymers of various molecular weight on solution viscosity as shown i n Figure 4 . Thi adhesives. At equal molecula tetrachain (or trichain), radial polymers than f o r linear polymers; or, at equal solution viscosity, one can use a radial tetrachain polymer of higher molecular weight. The same type of behavior persists with melt viscosity which i s important to processors of solid compounds. Figure 5 depicts the effect of structure on melt flow (8) and the same trends have been shown i n steady flow viscosity (J2) and Mooney viscosity (10). Clearly, the Theological behavior i s affected by the degree of branching. Frcm the viewpoint of the adhesives, rubber, or plastics fabricator, a branched product with higher molecular weight can be used with the same l e v e l of processability given by a lower molecular weight, linear product. This may not always prove advantageous but, i n many cases, higher molecular weight w i l l y i e l d some improvement. Properties of seme commercially available radial block polymers based on butadiene and styrene are shown i n Table I .

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

1.

HAWS

Thermoplastic Rubbers

3

Figure 1. Examples of butadiene-styrene copolymer structures

S/B (RANDOM) S - B (BLOCK) S - S/B S - B-S B - S-B (S - B) X (S - B) X S - S/B - S S - B - S - B - S 3

4

Figure

2. Linear and branched polymers

radial

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

NEW

INDUSTRIAL

SIMPLE BLOCK (S-B) . J

POLYBUTAOIENE (B) POLYSTYRENE (S)

LINEAR TELEBLOCK (S-B-S)

RADIAL TELEBLOCK (S-B) X N

Figure 3.

50,000

Structures of block polymers

100,000 150,000 MOLECULAR WEIGHT

Kautschuk und Gummi Kunststoffe Figure 4. Effect of structure on viscosity of 5% solutions in toluene (10)

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

POLYMERS

1.

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Thermoplastic Rubbers

TABLE I RADIAL BLOCK THERMOPLASTIC RUBBERS Solprene® Polymer Butadiene/Styrene Ratio Polystyrene, % of RHC Oil Content, phi^ Specific Gravity Melt Flow (180 C, 5 Kg), g/10 min Shore A Hardness 30(# Modulus, p s i Tensile Strength, psi Elongation, % Glass Transition," Tg (lower), C Tg (upper), C

411 70/30 29 0 0.94 nil 80 300

-87 110

414 60/40 39 0 0.95 2-4

406 60/40 39 0

475 60/40 39 50 0.'

0.95 nil

1-:

90 600

90 600

65 300

-92 102

-92 102

-85 82

a - Naphthenic o i l type. b - Temperature of maximum i n loss modulus at 35 Hertz. Polymers of this type dissolve readily i n a number of solvents and this plus high tensile without need for vulcanization provides an excellent product for use i n adhesives where a strong and flexible bond i s required. For other applications these products can be easily shaped using procedures common for thermoplastics yet provide elastic properties typical of rubbers at temperatures below the softening point of polystyrene. Set i s low at room temperature but w i l l of course be high i f deformation occurs at elevated temperatures followed by cooling. Recycling of scrap i s feasible since vulcanization i s not used. Stress-Strain Properties. Tensile strength improves with an increase i n styrene content (at least up to 50^ styrene) as shown i n Figure 6 or an increase i n molecular weight ( l l ) . The l a t t e r effect may not be evident at room temperature but i s more significant at elevated temperature or i n compounded stocks as i l l u s t r a t e d i n Tables II and I I I . Data i n Table II as well as reference ( l l ) also indicate that the high tensile observed at room temperature decreases as temperature i s raised thus limiting the maximum service temperature of these polymers.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

NEW

MELT FLOW, GRAMS

40

-

30

-

20 -

INDUSTRIAL

TRICHAIN \

TETRACHAIN

10 \LINEAR 0

• 60,000

i

1 00,000

140,000

Figure 5. Melt flow of teleblock polymers 70/30 butadiene/styrene (8)

100/0

80/20

60/40

40/60

BUTADIENE/STYRENE RATIO

Figure 6.

Effect of styrene content on hardness and tensile strength

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

POLYMERS

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Thermoplastic Rubbers

TABLE II MOLECULAR WEIGHT EFFECTS - 60/40 BUTADIENE/STIRENE

Molecular Wt.. Mw

80 F

130,000 250,000

4000 3800

Tensile, p s i 120 F 140 F 1800 2400

650 1800

TABLE III 8,

EFFECT OF MOLECULAR WEIGHT IN A COMPOUND

Flexures Molecular Wt., Mw 125,000 160,000 250,000

Mel Flow 183 43 0.2

a - Polymer (60/40 Bd/S) Hard Clay Naphthenic O i l Stearic Acid

560 630 1330

52 72 89

2,000 12,000 > 100,000

100 80 50 3

A l l properties except molecular weight are f o r the compounds. Hardness. A wide range i n hardness can be achieved by ( l ) variation of butadiene-styrene ratio i n the copolymer (Figure 6) and (2) manipulation of compounding ingredients such as f i l l e r s , o i l s and resins. O i l i s an inexpensive ingredient to reduce hardness i f i t s use can be tolerated. Hard clays, s i l i c a s or carbon blacks and polystyrenes are useful to increase hardness while materials such as whiting and polyindene resins have minimal effects on hardness. Hardness can also be i n fluenced by molding conditions, especially i f appreciable amounts of polystyrene are added to a compound. Data i n Figure 7 i l l u s t r a t e this point but i t must be emphasized that the effects can vary depending on the formulation, polymer type, rates of heating and cooling, etc. The formulation for results i n Figure 7 was as follows: Radial Block Polymer-Oil Masterbatch Whiting Oil Polystyrene Polyindene Resin Titanium Dioxide Stearic Acid

150 80 50 variable 20 10 3

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

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Shear Resistance (Adhesives). The resistance of adhesives based on butadiene-styrene polymers to failure under shear i s influenced by monomer ratio, molecular weight and branching (12, 8). As indicated i n these references, higher molecular weight, higher styrene and increased branching a l l lead to better shear resistance. Increases i n molecular weight and styrene also raise viscosity but increases i n branching reduce viscosity. At equal formulation viscosity, a tetrachain polymer gives excellent performance as shown i n Table IV taken from reference (8). TABLE IV TELEBLOCK POLYMERS AT EQUAL FORMULATION VISCOSITY

70/30 Butadiene/ Styrene Polymer

Molecular Weight

Formulatio Viscosity, CPS

Shea

Linear Trichain Tetrachain

84,000 136,000 182,000

1520 1580 1820

Hours to F a i l at 90 C 1.0 2.4 2.8

Peel Strength (AdhesivesK This property follows a trend similar to that f o r shear resistance and best peel strengths are obtained with f a i r l y high styrene (near 40$) and with high molecular weight polymers. Other considerations such as tack and viscosity may, however, dictate a l i m i t on increases i n molecular weight or styrene content. Abrasion. Resistance to abrasion i s adequate for many applications including footwear and can be improved by addition of reinforcing pigments (hard clay, s i l i c a s , carbon blacks) and through use of added plastic materials such as polystyrene or polyolefins. Abrasion resistance i s reduced by o i l s , some resins and large-particle f i l l e r s . I t i s also improved with increased molecular weight of the polymer (Table I I I ) . Crack Growth. good, especially i n and polystyrene a l l resistance to crack some ingredients.

Resistance to crack growth i s usually quite compounded stocks. Oils, resins, f i l l e r s have shown some beneficial effects on growth although there are optimum levels f o r

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

1.

HAWS

9

Thermoplastic Rubbers

Low Temperature Properties* B r i t t l e points or freeze points are quite low, due to the very low Tg of the rubbery polybutadiene portion, and even polymers with 40 or 50$ styrene may have low b r i t t l e temperatures. Soling compounds, for example, have displayed satisfactory resistance to cracking at -20 F. Coefficient of F r i c t i o n . This property depends on styrene level and on materials which may be added i n compounding but f a l l s i n the same range as other rubbers (natural rubber, SBR, etc.) rather than i n a lower range displayed by even the more flexible p l a s t i c s . Melt Processing Radial block polymers are relatively easy to process The temperature range for products i s f a i r l y broa soften the polymer and within certain limits on the high side t o avoid excessive stickiness or degradation. A preferred range i s generally between 250 and 350 F although higher temperatures may be desirable f o r some molding operations. Mixing.

Molding.

Internal Mixer Preferred Qycles Similar to Other Rubbery Polymers Heat Generated During Mixing Dump at Temperatures of 280-350 F Compression or Injection Methods Injection Preferred Cylinder Temperature - 350 F Range Mold Temperature - 120 to 150 F

Extrusion.

Low Compression Screw Preferred L:D Ratios - 10:1 to 25:1 Barrel Temperature - 240 to 340 F Die temperature - 280 to 340 F Preferred Melt Temperature - 275 to 375 F

The response of melt viscosity to changes i n shear rate over the range normally encountered i n mixing, extrusion and injection molding i s generally similar to that of thermoplastics such as polyethylene or polystyrene. Melt viscosities for a radial block polvmer based on butadiene and styrene, an o i l masterbatch and a compound based on the masterbatch are shown i n Figure 8. The compound shown contains o i l and f i l l e r s and would be suitable for injection molded soling. I t s viscosity i s i n the range of a molding grade polyethylene. The clear polymer shown 3 ,

a - The compound based on radial block polymer-oil masterbatch contains 110 phr total o i l , 90 phr f i l l e r and 80 phr polystyrene •

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

NEW

Figure 7.

Figure 8.

INDUSTRIAL

Effect of molding conditions

Melt viscosity vs. shear rate

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

POLYMERS

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11

i s more comparable i n viscosity to polystyrene or an extrusion grade polyethylene. Effects of injection pressure and temperature on flow of another compound based on a radial teleblock o i l masterbatch are i l l u s t r a t e d with spiral flow data i n Figure 9« Apparent viscosities at variable shear rates for this compound are much l i k e those shown earlier: 3,

Shear Rate, sec""^ 10 100 1000

Apparent Viscosity, poise 8.0x103 2.1 x 103 6.5 x 1 0 2

Compounding Ingredient F i l l e r s of variou blacks, s i l i c a s and clays may increase tensile at low levels but reduce tensile i f added i n large amounts. However, their use i s quite important f o r the beneficial effects that occur i n abrasion resistance and f l e x l i f e (crack growth). Whiting i s less beneficial but does improve f l e x l i f e . Polystyrene i s a useful additive. I t s use results i n improvements i n tear, abrasion and flex properties and i n higher hardness. Low density polyethylene has a similar effect and can be used i n moderate amounts. Other resins which impart useful properties include polyindenes, coumaroneindene, esters of hydrogenated rosin, mixed olefin resins, and a number of others. These various resins are especially interesting as modifiers i n both adhesives and thermoformed compounds - different resins w i l l affect the ratio of properties i n different ways - some increase melt flow with small effect on hardness while others have the reverse effect. Preferred o i l s are naphthenic or paraffinic i n nature, compatible with the polybutadiene portion of the polymer. Plasticizers compatible with th« polystyrene blocks tend to reduce strength. Blends of radial block rubbers with other polymers provide useful variations i n properties. Thermoplastics such as polyethylene and polystyrene have already been mentioned. There are several polymers which can be added to butadiene-styrene block a - Radial Block Polymer-Oil Masterbatch Whiting Oil Polystyrene Polyindene Resin Titanium Dioxide

150 80 50 60 20 10

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

NEW

Figure 9.

INDUSTRIAL

Spiral flow data

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

POLYMERS

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13

polymers t o provide ozone r e s i s t a n t products which a r e s t i l l strong and e l a s t o m e r i c without v u l c a n i z a t i o n . These i n c l u d e ethylene-oropylene copolymers, polyurethanes, neoprenes o r e t h y l e n e - v i n y l acetate polymers. P r o t e c t i o n a g a i n s t changes i n c o l o r o r p r o p e r t i e s caused by u l t r a v i o l e t r a d i a t i o n can be imparted by use o f f i n e l y - d i v i d e d grades o f z i n c oxide o r t i t a n i u m d i o x i d e . Carbon black i s e f f e c t i v e where i t can be used. A number of commercially a v a i l a b l e UV absorbers, i n c l u d i n g b e n z o t r i a z o l e s and benzophenones, a r e a l s o u s e f u l i n t h i s connection. Applications Consideration o f p r o p e r t i e s d i s c u s s e d h e l p s d e f i n e areas o f a p p l i c a t i o n . These areas a r e those which r e q u i r e e l a s t o m e r i c m a t e r i a l s and/or h i g h subjected t o e x c e s s i v e l t e l e b l o c k polymers g e n e r a l l y f a l l i n t o t h r e e c a t e g o r i e s ; ( l ) adhesives, (2) a r t i c l e s which a r e t h e r m a l l y formed by sheeting, e x t r u d i n g , molding, e t c . and (3) m o d i f i c a t i o n o f o t h e r e l a s t o m e r i c o r p l a s t i c polymers by b l e n d i n g . Adhesive a p p l i c a t i o n s can be widespread i n c l u d i n g contact cements, p r e s s u r e - s e n s i t i v e adhesives and hot m e l t s . I n s o l i d compounded a r t i c l e s footwear i s a l a r g e volume a p p l i c a t i o n such as molded-in-place s o l i n g or u n i t s o l e s t o be cemented t o uppers. A d d i t i o n a l uses a r e i n t o y s , m i l k t u b i n g , cove base, mats and miscellaneous coatings or molded p a r t s . P o t e n t i a l uses i n c l u d e blends with ethylene-propylene rubber and e t h y l e n e - v i n y l a c e t a t e copolymers t o provide οzone-resistant formulations o r blends t o improve crack- o r impact-resistance o f p l a s t i c s . Literature Cited 1.

4·

R a i l s b a c k , Η . E., B i a r d , C. C., Haws, J. R. and Wheat, R.C., Rubber Age (1964) 94, 583. B a i l e y , J. T., Bishop, E . T., Hendricks, W. R., Holden, G. and Legge, N. R., Rubber Age (1966) 98, 69. Kraus, G. and R a i l s b a c k , H. E., Paper oresented a t "ACS Symposium on Recent Advances in Polymer Blends, G r a f t s and Blocks" (August, 1971). Kraus, G. and Graver, J. T., J. A p p l . Polym. Sci. (1967)

5.

A r n o l d , K. R. and Meier, D. J . , J. Appl. Polymer Sci., (1970)

2. 3·

11, 2121. 14, 427. 6. 7.

Moacanin, J . , Holden, G. and Tschoegl, N. W., E d i t o r s "Block Copolymers", J. P o l y . Sci., C. (1969) No. 26. Z e l i n s k i , R. P. and C h i l d e r s , C. W., Rubber Chem. Technol.,

(1968) 14, 161.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

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Marrs, O. L., Zelinski, R. P. and Doss, R. C., Paper presented at the 104th Meeting of the ACS Rubber Division, Denver (October, 1973). 9. Kraus, G., Naylor, F. E. and Rollmann, K. W., J . Poly. S c i . , A-2 (1971) 9, 1839. 10. Railsback, H. E. and Zelinski, R. P., Kautschuk und Gummi Kunststoffe(1972) 25, 254. 11. Haws, J . R. and Middlebrook, T. C., Rubber World (1973) 167, 27. 12. Marrs, O. L., Naylor, F. E. and Edmonds, L. O., J . Adhesion (1972) 4, 211.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

2 A New Thermoplastic Syndiotactic 1,2-Polybutadiene. I. Production, Fundamental Properties, and Processing YASUMASA TAKEUCHI, AKIRA SEKIMOTO, and MITSUO ABE* Butadiene Resin Development Dept., Japan Synthetic Rubber Co., Ltd., No. 1, 1-chome Kyobashi, Chuo-ku, Tokyo, Japan

A new thermoplastic s y n d i o t a c t i c 1, 2-polybutadiene ( 1 , 2PBD) has been developed by Japan Synthetic Rubber Co., Ltd.(JSR). The polymer is o f more than 90% 1, 2-unit content, with crystallinity c o n t r o l l e d between 15 and 25% 1 and the weight-average molecular weight o f the polymer is more than 100,000. Many papers on s y n d i o t a c t i c 1, 2-PBD have been reported f o r a long time. As the polymers reported there had a high c r y s t a l linity (>40%) and high melting p o i n t , they were r a t h e r difficult to process with o r d i n a r y p l a s t i c s machines without d e t e r i o r a t i o n o f the polymer because o f t h e i r high molding temperatures. On the other hand, s i n c e the crystallinity o f the new 1, 2-PBD is c o n t r o l l e d between 15-25%, the melting point is kept below 90°C. Consequently, the 1, 2-PBD does not d e t e r i o r a t e during processing in the molding machine. JSR is the first in the world to succeed in developing a unique 1, 2-PBD, which can be processed with conventional p l a s t i c s molding machines. Meanwhile, since the s t r u c t u r e o f 1, 2-PBD has two chemical r e a c t i v e s i t e s , which are (1) hydrogen bonded to the t e r t i a r y carbon atom and to the a l l y l p o s i t i o n and (2) the v i n y l group, t h i s polymer may be regarded as a novel f u n c t i o n a l polymer, namel y , as a r e a c t i v e thermoplastic. Having found the new c a t a l y s t system in 1966, JSR has engaged f o r the past seven years i n fundamental research, a p p l i c a t i o n research and development, process development, and marketing research. As a r e s u l t , JSR has decided on the commercialization o f 1, 2-PBD and constructed a p l a n t o f 5,000MT/Y a t the end o f 1973. The p l a n t is under expansion to 10,000MT/Y and will be completed a t next s p r i n g . JSR has filed more than 107 patents concerning production and a p p l i c a t i o n s o f 1, 2-PBD throughout the world. * Research Laboratory o f JSR No. 100, Kawajiri-cho, Y o k k a i c h i - s h i , Mie-ken. 15

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

16

NEW

PRODUCTION OF A NEW

SYNDIOTACTIC 1,

INDUSTRIAL

POLYMERS

2-POLYBUTADIENE

JSR 1, 2-PBD i s produced by s o l u t i o n polymerization technique using Z i e g l e r type c a t a l y s t system containing Co Compound as one component. The r e p r e s e n t a t i v e c a t a l y s t system c o n s i s t s o f Co h a l i d e - L i g a n d - t r i a l k y l aluminum-^O. A l l i n g r e d i e n t s i n t h i s c a t a l y s t system are indispensable component f o r 1, 2-polymerizat i o n of butadiene, because the polymerization o f butadiene can not be obtained from the Co h a l i d e - A l R j and Co halide-Ligand-AlR-j systems, alone. The Co halide-AlR-j-^O system i s the c a t a l y s t f o r c i s 1, ^-polymerization o f butadiene. Adding the l i g a n d to the c i s 1, 4-polymerization c a t a l y s t system, we can o b t a i n 1, 2polybutadiene. Therefore, as f a r as the production o f our 1, 2PBD i s concerned, the most important i n g r e d i e n t s are l i g a n d and HpO. The above mentioned r e l a t i o n s are summarized as f o l l o w s :

C0X2

-

AIR3

C0X2 - Ligand - AIR C0X2 - AIR3 - H2O C0X2 - Ligand - A l R j - H2O

N No p o l y m e r i z a t i o n C i s - 1 , k polymerization 1, 2 polymerization

The r o l e s o f H2O i n 1, 2-polymerization o f butadiene are shown i n F i g . 1. When H 0/A1 = 1.0, Y i e l d , 1, 2-unit contents and molecular weight show maximum value. Considering the general Z i e g l e r type c a t a l y s t aspects, i t i s s u r p r i s i n g that such a l o t o f H2O to A l R j i s necessary f o r p o l y m e r i z a t i o n . 2

SOME FUNDAMENTAL PROPERTIES S t r u c t u r e o f 1-,

2-polybutadiene

C1 2) 1, 2-unit content was more than 90% by IR a n a l y s i s ^ As shown i n F i g . 2, the polymer does not c o n t a i n any trans 1, ku n i t s . The absorbance a t 7*f5em-1 i n d i c a t e s the existence o f small amounts o f c i s 1, 4 - u n i t . By X-ray d i f f r a c t i o n s t u d i e s , 2 0 of 1, 2-PBD was the same as that o f the s y n d i o t a c t i c 1, 2PBD reported by G. N a t t a ^ ) , as shown i n F i g . 3* The t a c t i c i t y o f 1, SrPBD was analyzed by V.D. M o c h e l s 3 c NMR s p e c t r a m e t h o d ^ using a JEOL JNM-PS/PFT-100 spectrometer a t 25-15 MHz;As shown i n Table 1, there i s no i s o t a c t i c 1, 2-PBD. The syndiot a c t i c content i n c r e a s e s w i t h i t s c r y s t a l l i n i t y and i s much g r e a t e r than h e t e r o t a c t i c content. 1

f

Table 1. Crystallinity

T a c t i c i t y o f JSR 1,

2-polybutadiene Tacticity

Microstructure c i s t r a n s 1, 2 {%)

18 25

1

10 8

(%)

0 0

(%)

90 92

0 0

49 3^

51 66

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

2.

TAKEUCHI

Figure 3.

ET AL.

Thermoplastic

1,2-Polybutadiene

X-ray diffraction diagram of l£-polybutadiene

Figure 4. DSC thermogram of 1,2polybutadiene having 25% crystallinity at 16°C/min.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

17

18

NEW

INDUSTRIAL

POLYMERS

As the r e s u l t s o f X-ray and NMR a n a l y s i s , i t i s confirmed that the polymer i s s y n d i o t a c t i c 1, 2-polybutadiene. The c r y s t a l l i n i t y was determined by the d e n s i t y gradient tube method. We assumed that the d e n s i t y o f 100$ c r y s t a l l i n i t y i s 0.963(5) and the d e n s i t y o f 0$ c r y s t a l l i n i t y i s 0 . 8 9 2 . 1, 2PBD o f 0$ c r y s t a l l i n i t y was synthesized by a JSR c a t a l y s t system and i t was confirmed that i t was amorphous by X-ray a n a l y s i s . The DSC curve o f 1, shown i n F i g . k. It is l i n e s i z e i s broad. We thermic peak o f the DSC

2-PBD a s having 25$ c r y s t a l l i n i t y i s assumed that the d i s t r i b u t i o n o f c r y s t a l have not d i s c o v e r e d yet why the endoi s broad.

Even low c r y s t a l l i n e 1, 2-PBD a t 25$ c r y s t a l l i n i t y has f i n e c r y s t a l l i n e s , as shown amorphous 1, 2-PBD prepare c r y s t a l l i n e s (photograph I I ) . Molecular C h a r a c t e r i z a t i o n o f 1,

2-polybutadiene

GPC data were measured with a Model 200 o f the Waters Co. the r e s u l t i s shown i n F i g . 5- Although the p o l y m e r i z a t i o n i s c a r r i e d out by Z i e g l e r type c a t a l y s t , the molecular d i s t r i b u t i o n of the 1, 2-PBD i s r a t h e r sharp. The r e s u l t s o f the molecular c h a r a c t e r i z a t i o n o f the 1, PBD are t a b u l a t e d i n Table 2. Table 2 .

Molecular c h a r a c t e r i z a t i o n o f JSR 1, 18

C r y s t a l l i n i t y ($) Intrinsic viscosity (30°C, toluene) Mn x 10-J* Mw x 10"^ Mw/Mn X x 10XMw 7

1.H

11.1 20.6 1.9 0.3 0.6

2-

2-polybutadiene 25

1.82 12.2 y\A

2.6

OA

1A3

1.71

10.7 17.7 1.7 0 0

12.1 23. *t 1.9 0.03 0.1

Since X and X Mw are almost zero, i t i s assumed that the long branch o f 1, 2-PBD having 25$ c r y s t a l l i n i t y i s almost zero, but the branches tend t o i n c r e a s e with the r e d u c t i o n o f the c r y s t a l l i n i t y . The v i s c o s i t y molecular weight equation(6) used was ]=s 9*1 x 10~5 x Mn**°° and the measurement o f the v i s c o s i t y was c a r r i e d out i n toluene, a t 30°C. Physical Properties Some p h y s i c a l p r o p e r t i e s o f 1,

2-PBD o f 25$ c r y s t a l l i n i t y

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

2.

TAKEUCHI

ET AL.

Thermoplastic 1,2-Polybutadiene

19

(Butadiene Resin, JSR RB820) were evaluated i n accordance with v a r i o u s t e s t i n g methods and are shown i n Table 3- Roughly speaking, i t seems t o be q u i t e a l l r i g h t to consider that the propert i e s o f 1, 2-PBD are s i m i l a r to LDPE with g r e a t e r e l o n g a t i o n , except i t s thermal p r o p e r t i e s . Tg and Tm a r e determined by DSC. As shown i n F i g . k, the determination o f Tm i s u n c l e a r because o f two broad peaks. However, we decided that the temperature o f the main peak can be regarded as Tm. Because Tg o f the polymer i s -23°C, t h i s p o i n t must be considered i n u s i n g 1, 2-PBD a t extremely low temperatures. A t y p i c a l s t r e s s - s t r a i n curve o f 1, 2-PBD compared with LDPE and rubber i n d i c a t e s that the 1, 2-PBD has intermediate p r o p e r t i e s between p l a s t i c s h i p between "dynamic e l a s t i 2-PBD having 2% c r y s t a l l i n i t y i s shown F i g . 7. The E o f 1, 2PBD i s s i m i l a r to that o f EVA and smaller than that o f LDPE above kO°C. The E o f 1, 2-PBD i s the s m a l l e s t than those o f EVA and LDPE below 20°C. Chemical P r o p e r t i e s Since each monomer u n i t o f 1, 2-PBD has (1) the hydrogen bonded to t e r t i a r y carbon atom and to the a l l y l p o s i t i o n , and (2) a v i n y l group, the polymer i s can be a c t i v a t e d by heat, U.V. and other energy sources. A l s o , 1, 2-PBD can be e a s i l y made t o r e a c t with other chemical reagent due to i t s chemical r e a c t i v i t y . The s t a b i l i t y , very important from the i n d u s t r i a l p o i n t o f view, can be c o n t r o l l e d by choice o f k i n d s and q u a n t i t i e s o f v a r i o u s s t a b i l i z e r s . I f 1, 2-PBD contains only thermal s t a b i l i z e r s , the polymer i s d e t e r i o r a t e d w i t h i n a few months under outdoor exposure. E s p e c i a l l y , i n summer, the t h i n f i l m i s d e t e r i o r a t e d w i t h i n a few weeks. Thus, 1, 2-PBD i s considered to be a photodegradable p l a s t i c s . F i g . 8 shows the p o s s i b i l i t i e s of i t s l i f e c o n t r o l through the use o f v a r i o u s s t a b i l i z e r s . The photodegradation o f the 1, 2-PBD i s caused by the c r o s s l i n k i n g r e a c t i o n , o f which we explained a t a conference i n Nov. 1973(77. The photodegradation does not occur i n the presence o f l i g h t o f more than 350 m/i. i n wave l e n g t h , as shown i n Table k. 1, 2-PBD i s s t a b l e under o r d i n a r y i l l u m i n a t i o n lamps i n i t s l i g h t - d e t e r i o r a t i o n . A l s o , when covered with an opaque s u r f a c e , the polymer i s safe and s t a b l e f o r a long time. The chemical r e a c t i v i t y o f 1, 2-PBD i s s i m i l a r t o the l i q u i d 1, 2-polybutadiene. I n d u s t r i a l l y a p p l i c a b l e r e a c t i o n s may be the ene a d d i t i o n r e a c t i o n , c r o s s - l i n k i n g r e a c t i o n and g r a f t p o l y merization.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

20

NEW

INDUSTRIAL

POLYMERS

20

Electron micrographs of l£-poly butadiene. I: crystallinity 25%; II: amorphous.

Figure 5. CPC chromatogram of syndiotactic 1,2-polybutadiene (crystalUnity: 25% )

200

Figure 6. Stress-strain curve of 1J2polybutadiene [(crystallinity: 25% [7/] (30°C, toluene) = 1.3)]

Figure 7. Relationship between dynamic elastic modulus and temperature of 1£-PBD (crystallinity: 25%) compared with LDPE and EVA

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

TAKEUCHI

Thermoplastic 1,2-Polybutadiene

ET AL.

Table 3 .

Typical properties o f syndiotactic 1, 2-polybutadiene

Properties

T e s t methods

Crystallinity

Determined values

Units

%

Density-gradient tube method

25

Intrinsic viscosity, (toluene, 30 C . )

1.3

Microstructure 1, 2 - b o n d content

Infrared absorption s p e c t r u m

Density

Density-gradient

M e l t index; 1 5 0 ° C ,

%

90 0. 91

216

Thermal properties: Softening point ( V i c a t ' s test)

ASTM

G l a s s t r a n s i t i o n point

(DSC

method)

C.

-23

M e l t i n g point

(DSC

method)

C.

90

D1525

60

C

Tensile properties: 300% t e n s i l e

strength

T e n s i l e strength at f a c t u r e T e n s i l e elongation at b r e a k H a r d n e s s (Shore test)

hardness

A S T M D638

kg. / c m

2

.

90

A S T M D638

kg. / c m

2

.

110

A S T M D638

410

%

31

A S T M D1706

strength

ASTM

D790

kg. / c m .

47

Bending modulus

ASTM

D790

kg./cm .

560

Izod i m p a c t strength (room temperature)

A S T M D256

Bending

2

2

kg . c m . / c m ^ . D o e s not break.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

NEW

22

INDUSTRIAL

POLYMERS

s

1 i UJ 0

s

1

11 • TRST l "mil pMiiTiT^—' "L" 0

2

4

6

8

10

Exposure Time ( days )

Exposure period;

Nov. 1-Nov.

Exposure location;

Yokkaichi. Japan

Figure 8. Weathering test of syndiotactic l£-polybutadiene film by outdoor exposure

I

/f

10' - // ft

//

/I

/// /

.t

// ft /

/

f~wf

/ /'

: AO /n full-flight screw L/ = 24, C.R.s 2.0 m

— r

Die

: spiral die

5

Shear stress

75 "Vm $ x 0.7 mm

Preset temp.: CtOOO'O C (120*C) C (130"C) Die (M0*C) 2

Screw rotation :

10

4

Table 5* Representative processing condition of syndiotactic 1, 2-polybutadiene ( c r y s t a l l i n i t y : 25%, ( ^ ) =1-3)

D

/

10

v

Extruder -1.2-PBD LC)P E

f

Figure 9. Relationship between -q and y of syndiotactic l£-polybutadiene (crystallinity: 25%, [ ] = 1.3)

3

40 r.p.m.

10

6

(dyne/W)

Figure 10. Relationship between r and y of syndiotactic IJZ-polybutadiene (crystallinity: 25% =1.3) w

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

TAKEUCHI

Thermoplastic 1,2-Polybutadiene

ET AL.

Table k.

Dominant Wave - Length Radiated (nry*. )

Lamp-Model

GL

FL

P h o t o d e g r a d a b i l i t y o f s y n d i o t a c t i c 1, 2-polybutadiene e f f e c t o f wave l e n g t h of l i g h t *

15

20 SE

Light Intensity at Surface of Sample (mW/cm )

Energy Level of Dominant Wave-Length ( Kcoi/mol )

1

Radiation Level Required for Occurring Degradation ( mW-Hr/cm ) 2

254

12.0

112

Less than 120 ( 10 Hr }

314

12.6

86

Less than 250 ( 20 Hr ) Less than 600

FL 20 SBLB

352

FL20 SW/NL

582

*

Produced

Table 6.

50

11.8

by Tokyo

Shibaura Electric

Co., Ltd.

TEST ITEM

NO. 434

I. I. 3. 4. 5.

PHENOL FORMALDEHYDE HEAVY METALS RESIDUE ON EVAPORATION POTASSIUM PERMANGANATE-REDUCING SUBSTANCES

NO. 301

1. I.

HEAVY METALS EXTRACTIVE SUBSTANCES I. TRANSPARENCY AND APPEARANCE II. PH (THE DIFFERENCE TO THE BLANK SOLUTION) III. HEAVY METALS IV. POTASSIUM PERMANGANATE-REDUCING SUBSTANCES V. RESIDUE ON EVAPORATION ACUTE SYSTEMIC TOXICITY

DISPOSABLE BLOOD DONOR SET AND SOLUTION ADMINISTRATION SET SPECIFICATION FOR PLASTICS USED IN MEDICAL PRACTICE

degraded

T e s t i n g items o f some Japanese Regulations used to confirm the n o n t o x i c i t y o f s y n d i o t a c t i c 1, 2-polybutadiene

REGULATION NO. SPECIFICATION FOR PLASTICS PACKAGING FOR FOODS

Not

3. NO. 278

1.

DISPOSABLE BLOOD OXYGENATOR SET

2. 3.

EXTRACTIVE SUBSTANCES I. TRANSPARENCY AND APPEARANCE III. PH (THE DIFFERENCE TO THE BLANK SOLUTION) IV. POTASSIUM PERMANGANATE-REDUCING SUBSTANCES V. RESIDUE ON EVAPORATION VI. ZINK VII. LEAD HEMOLYSIS TEST PYROGEN TEST

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

NEW

24

INDUSTRIAL

POLYMERS

PROCESSING CONDITION The r e l a t i o n between 97 and t ( v i s c o s i t y and shear r a t e ) , the t h e o l o g i c a l behavior o f 1, 2-PBD, i s shown i n F i g . 9. ^ vs t curves o f 1, 2-PBD and LDPE have a very s i m i l a r appearance. A l s o , the r e l a t i o n between -£ and "jf (shear s t r e s s and shear r a t e ) i s s i m i l a r to LDPE ( F i g . 10). Since the Melt Flow Index o f t h i s LDPE i s 4, the 1, 2-PBD i s regarded as a h i g h flow r e s i n . Therefore, i t i s assumed that the p r o c e s s i n g c o n d i t i o n o f 1, 2PBD i s almost the same as that o f LDPE. A c t u a l l y , having examined many times the p r o c e s s i n g o f the 1, 2-PBD, we have found that the polymer can be processed by o r d i n a r y molding machine, under due care to the thermal s t a b i l i t y o f the 1, 2-PBD. For example, the t h i f i l m f 1 mad b o r d i nary T-die e x t r u s i o n an t i v e processing condition , 5 The p r e s e t temperature i s an important p r o c e s s i n g c o n d i t i o n . Of course, i t depends on the mechanism o f p r o c e s s i n g machine. And i t i s d e s i r a b l e to keep the temperature under 140°C. Another r e q u i r e d c o n d i t i o n i s a s p e c i a l technique f o r c o o l i n g o f the molding, because o f i t s low melting p o i n t . N0NT0XICITY OF JSR 1, 2-POLYBUTADIENE The a d d i t i v e s used i n the p r o d u c t i o n o f 1, 2-PBD, such as thermal s t a b i l i z e r s , a n t i o x i d a n t s , l u b r i c a n t s , a n t i - f o g g i n g agents, U.V. absorbers and others, should be only those which have been approved by the F.D.A. Therefore, i t may be a l l r i g h t to consider that the 1, 2-PBD i s safe f o r food. However, we attempted to o b t a i n some t e s t r e s u l t s about the n o n t o x i c i t y o f the polymer and examined the Regulations o f the M i n i s t r y of Health and Welfare of Japan. The t e s t items used to confirm the n o n t o x i c i t y o f the 1, 2-PBD tabulate i n Table 6. No.' K$k i s the s p e c i f i c a t i o n f o r p l a s t i c packaging f o r foods, except PVC. No. 273 and No. 301 are the s p e c i f i c a t i o n f o r p l a s t i c s used i n medical p r a c t i c e , i n Japan. These t e s t i n g items c o n s i s t o f e x t r a c t i o n t e s t , heavy metal a n a l y s i s , acute t o x i c i t y t e s t , hemolysis t e s t and pyrogen t e s t . A l l the r e s u l t s o f the examinat i o n passed the r e g u l a t i o n s and i n d i c a t e that the 1, 2-PBD i s safe enough to be used as a p l a s t i c packaging f o r foods. In the case o f acute t o x i c i t y , the number o f deaths o f the mice was zero. F u r t h e r , i t i s assumed that the 1, 2-PBD has the p o s s i b i b i l i t y to be a p p l i e d to the medical p l a s t i c s f i e l d .

ACKNOWLEDGEMENTS

Ltd.

The authors would l i k e to thank Japan S y n t h e t i c Rubber Co., f o r the permission to p u b l i s h t h i s i n the symposium. We are

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

2.

TAKEUCHI

ET AL.

Thermoplastic 1,2-Polybutadiene

25

g r a t e f u l f o r the help given by Mr. N. Nomura, Mr. 0. Nomura and Mr. K. Kawamoto, I l l u m i n a t i o n Laboratory, Tokyo Shibaura E l e c t r i c Co., L t d .

REFERENCE 1)

Y. Tanaka, Y. Takeuchi, M. Kobayashi and H. Tadokoro, J . Polymer S c i . , A - 2 , 9 , 43 (1971)

2)

D. Morero, A. Santambrogio, L. P o r r i and F. C l a m p e l l i , Chim. e Ind., 41, 758 (1959)

3)

G. Natta, Makromol. Chem., 16, 213 (1955)

4)

V.D. Mochel, J. Polyme

5)

G. Natta, J. Polymer S c i . , 2 0 , 251

6)

JSR; unpublished data

7)

Y. Takeuchi, Y. H a r i t a and A. Sekimoto, Conference on " D e g r a d a b i l i t y o f Polymers and Plastics" 27, 28 Nov. 1973

(1956)

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

3 A New Thermoplastic Syndiotactic 1,2-Poylbutadiene. II. Applications YASUMASA TAKEUCHI, AKIRA SEKIMOTO and MITSUO ABE* Butadiene Resin Development Dept., Japan Synthetic Rubber Co., Ltd., No. 1, 1-chome, Kyobashi, Chuo-ku, Tokyo, Japan

A new thermoplastic s y n d i o t a c t i c 1, 2-polybutadiene (1, 2PBD) have been developed by Japan S y n t h e t i c Rubber Co., L t d . (JSR). The 1, 2-PBD is a low c r y s t a l l i n e polymer (15-25% c r y s t a l linity) and a unique thermoplastic having property between p l a s t i c and rubber. On the other hand, the 1, 2-PBD is regarded as a novel f u n c t i o n a l polymer, namely, as a r e a c t i v e t h e r m o p l a s t i c . The c h a r a c t e r i s t i c p o i n t s o f 1, 2-PBD are summarized as f o l l o w s ; (1) S a f e t y f o r food (2) high r e a c t i v i t y (3) good transparent (4) pliability and flexibility (5) photodegradability. Its p o s s i b l e a p p l i c a t i o n s are very wide from above described characteristics. I t may fairly be s a i d that its a p p l i c a t i o n s cover all the polymer's field l i k e Figure I which are shown s c h e m a t i c a l l y some o f it's p o s s i b l e a p p l i c a t i o n s . Thermoplastics * Thermosetting

Resin

N

JSR 1, 2-PBD

CoatingRubber Figure 1.

Application fields of JSR 1,2-polybutadiene

The 1, 2-PBD can be a p p l i e d t o f i l m s and tubes in thermoplastics field. In rubber f i e l d , c r o s s - l i n k i n g foam l i k e EVA is a p o s i b i l i t y . I n c o a t i n g s , photo-curing p a i n t i s a p o s s i b i l i t y .

* Research Laboratory o f JSR No. 100, Kawajiri-cho, Y o k k a i c h i - s h i , Mie-ken

26

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

3.

TAKEUCHI

ET AL.

1,2-Polybutadiene

Applications

27

In the adhesion f i e l d , hot-melt type adhesive i s a p o s s i b i l i t y . In the f i b e r f i e l d , graphite f i b e r i s a p o s s i b i l i t y . In other f i e l d s , p h o t o - s e n s i t i v e polymer i s a p o s s i b i l i t y . We w i l l describe the f o l l o w i n g some o f p o s s i b l e a p p l i c a t i o n s o f the 1, 2-PBD that a r e u s e f u l from an i n d u s t r i a l view p o i n t . APPLICATION EXAMPLES IN THERMOPLASTIC FIELD We developed the s t r e t c h f i l m o f the 1, 2-PBD as a represent a t i v e example i n thermoplastics f i e l d (photograph I , I I ) . The general p h y s i c a l p r o p e r t i e s o f 1, 2-PBD f i l m are shown i n Table 1 compared with f i l m p r o p e r t i e s o f other s o f t p l a s t i c s commercially a v a i l a b l e . The datas show that 1, 2-PBD f i l m i s comparable to c a l strength. The c h a r a c t e r i s t i summarized as f o l l o w s : 1) 2) 3) k) 5) 6) 7)

Good transparency High gas p e r m e a b i l i t y Good elongation and s t r e t c h High tear r e s i s t a h c e (Elemendorf) High c o e f f i c i e n t o f f r i c t i o n P l i a b i l i t y and f l e x i b i l i t y Lower h e a t - s e a l i n g temperature and high welding efficiency

The gas p e r m e a b i l i t y o f 1, 2-PBD depends on the f i l m t h i c k ness, as shown i n F i g . 2 . When the f i l m thickness i s increased to s e v e r a l few m i l l i m e t e r s , the gas permeability o f 1, 2-PBD i s reduced and approaches that o f LDPE. In t h i s f i l m the gas permea b i l i t y o f 1, 2-PBD i s high, which i s assumed t o be a t t r i b u t a b l e to the good s o l u b i l i t y o f CO2, O2 and ethylene oxide gas i n the 1, 2-PBD f i l m surface, i n view o f the small gas d i f f u s i o n c o e f f i c i e n t o f 1, 2-PBD measured by J.D. F e r r y e t a l ( 2 ) . From these fundamental p h y s i c a l p r o p e r t i e s and nontoxic i n respect t o food hydiene described previous paper ^ , the 1, 2-PBD w i l l be s u i t a b l e f o r food packaging m a t e r i a l s . Because o f i t s good gas p e r m e a b i l i t y i n t h i s f i l m , 1, 2-PBD i s used, as the most s u p e r i o r a p p l i c a t i o n example, f o r s t r e t c h e d f i l m as a wrapping f o r f r e s h vegetables, f r u i t s and o t h e r s .

APPLICATION TO EVA SPONGE FIELD We have developed many kinds o f c e l l u l a r sponge i n s t e a d o f EVA sponge u t i l i z i n g i t s r u b b e r - l i k e p r o p e r t i e s and r e a c t i v i t y with chemical reagents. The 1, 2-PBD sponge i s superior to EVA i n the f o l l o w i n g p o i n t s .

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

NEW

INDUSTRIAL

POLYMERS

Photo I. Stretch film and pellets of syndiotactic 1 ^-polybutadiene

Photo II. Some packaged fresh foods with syndiotactic 1^-polybutadiene stretch film

Photo III. Various kinds of cellular sponge shoe soles made of syndiotactic 1 ^-polybutadiene

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

ACS

In New Industrial Polymers; Deanin, R.; Symposium Series; American Chemical Society: Washington,

DC,

blow blow blow

2 sec)

C

2

ratio » 2.5 ratio = 2 . 5 , V A c . cont. , 12% ratio = 2 . 5 , plastitizer 50%

2

Optimum heat-sealing temperature (2 k g / c m ,

Water vapor permeability

°2 Ethylene oxide g- 0. 1mm/ m -24 hrs.

C C - 0. 1mm/ m - 24 h r s aim

Gas permeability co

JIS Z 0208

ASTM D 1434

ASTM D 1003

%

Haze

2

ASTM D 1003

%

JIS Z 1702

JIS Z 1702

JIS Z 1702

Testing methods

Light transmittance

2

kg/cm

T e a r resistance Machine direction T r a n s v e r s e direction

F r i c t i o n angle

%

Elongation Machine direction T r a n s v e r s e direction

2

Unit

kg/cm

/>

Tensile strength Machine direction T r a n s v e r s e direction

g/cc

Density

Test item

75 ^ 8 0

110

31,000 7, 100 320,000

1

91

>70

97 150

500 710

180 170

50

0.91

75 ~ 8 0

98

28,000 6,000

1

91

>70

78 76

500 570

200 200

50

0.91

JSR 1, 2 - P B D T-die " * extrusion inflation

100

25

7, 900 1, 500 20,900

14

80

10

13 33

290 410

170 140

53

0. 92

LDPE

80—85

45

11,400 1, 800

6

88

45

15 19

400 560

175 180

47

0. 93

EVA'"'

1,

85 —90

100

3,000 9, 300

1

91

>70

58 67

240 240

250 250

47

1. 26

Soft"** PVC

Comparison o f g e n e r a l p h y s i c a l p r o p e r t i e s o f s y n d i o t a c t i c 2-Polybutadiene ( c r y s t a l l i n i t y : 2%, [ ^ J = 1.3) f i l m s and f i l m s o f s o f t p l a s t i c s commercially a v a i l a b l e .

F i l m thickness

Table 1.

30

NEW

1) 2) 3) k) 5) 6) 7)

INDUSTRIAL

POLYMERS

The process r e q u i r e s only one step cure Wide range adjustment o f the expansion r a t i o i s p o s s i b l e C e l l s i z e o f the sponge i s uniform High f i l l e r l o a d i n g i s p o s s i b l e Compression set i s smaller than EVA Adhesion i s easy Performance c o a t i n g with p a i n t i s good

In sponge production, 1, 2-PBD can be loaded with f i l l e r s and cured with s u l f u r , while EVA cannot be cured with s u l f u r , only with peroxide. F i g u r e 3 shows the cure curves obtained with a JSR Curelastometer using s u l f u r c u r i n g system. The cure r a t e o f 1, 2-PBD i s s i m i l a r to t h a t o f SBR. C o n s i d e r i n g t h a t the cure agent o f EVA i s r e s t r i c t e d only to peroxide, the 1, 2-PBD agent i s concerned. Tabl a b i l i t y t e s t q u a l i t a t i v e l y obtained with specimens prepared i n accordance with some f o r m u l a t i o n . The c r o s s - l i n k i n g products of the 1, 2-PBD show e x c e l l e n t w e a t h e r a b i l i t y and ozone r e s i s t a n c e l i k e that o f EPDM. T h i s i s s u r p r i s i n g , c o n s i d e r i n g i t s poor w e a t h e r a b i l i t y on non c r o s s - l i n k i n g products. Some Japanese companies have developed c e l l u l a r sponge i n t o many k i n d s o f shoe s o l e s , as shown photograph I I I . R e s u l t s from p r a c t i c a l use have confirmed that these sponges have the same d u r a b i l i t y as rubber sponges.

APPLICATIONS IN THERMOSETTING RESIN FIELD F i r e s t o n e ( 3 ) has a l r e a d y reported that l i q u i d 1, 2-PBD can be used f o r i n s u l a t i n g m a t e r i a l s l i k e the u s u a l thermosetting r e s i n s . I n s u l a t i n g m a t e r i a l s o f cured s y n d i o t a c t i c 1, 2-PBD p l u s f i l l e r s show as good p r o p e r t i e s as those o f l i q u i d 1,

2-PBD.

APPLICATION TO PHOTO-SENSITIVE POLIMER FIELD Since 1, 2-PBD i s e a s i l y cured by U.V. i r r a d i a t i o n , i t can be regarded as a p h o t o - s e n s i t i v e polymer. I f a p h o t o - s e n s i t i z e r i s added to 1, 2-PBD, the s e n s i t i v i t y o f the compounds i s s i m i l a r to t h a t o f other commercial photo-polymers. Moreover, adding a c r o s s - l i n k i n g agent l i k e d i a z i d compound, the compound c o n t a i n i n g these three components i n d i c a t e s i t s s u p e r i o r s e n s i t i v i t y compared with other p h o t o - s e n s i t i v e polymers. For example, adding k% o f p h o t o - s e n s i t i z e r (p, p tetramethyl-diamino-benzophenone) to the polymer, the 1, 2-PBD was c r o s s - l i n k e d by U.V. i r r a d i a t i o n (low pressure mercury lamp, f

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

TAKEUCHI

ET AL.

1,2-Polybutadiene

Applications

31

"50 100 " F i l m thickness (M)

Figure 2. Relationship between film thickness and C0 gas permeability

Cure time (min.)

Figure 3.

2

Table 2.

Cure curves obtained with JSR curelastometer

Comparison between 1, 2-PBD and v a r i o u s rubbers i n outdoor exposure w e a t h e r a b i l i t y t e s t Time of Exposure: Location:

one month in summer

Kobe City, Japan Outdoor Exposure Test Results

White stock formulation

Change in hardness

SBR > BR > EPDM > l,2-PBD

Change in Tensile strength

SBR > EPDM > BR = 1.2-PBD

Change in Elongation

BR > SBR > 1,2-PBD = EPDM

Crack appearance (after 30 days' exposure)

Black stock formulation

BR > SBR > 1,2-PBD > EPDM (muth) (little) (slight) (none)

Change in color

BR > SBR > EPDM > 1,2-PBD

Change in hardness

BR = EPDM > SBR > 1,2-PBD

Change in Tensile strength

EPDM = SBR > BR »

Change in Elongation Crack appearance (after 30 days' exposure)

1,2-PBD

BR > 1,2-PBD = EPDM > SBR SBR = BR » (much) (little)

1,2-PBD = EPDM (none) (none)

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

32

NEW

INDUSTRIAL

POLYMERS

d i s t a n c e 5cm) and the exposed step numbers o f the step t a b l e t (21 steps) made by Kodak Co. f o r the purpose o f measuring the photos e n s i t i v i t y put the 19th step a t 30 sec. I t i s suggested that h i g h p h o t o - s e n s i t i v i t y o f 1, 2-PBD makes u s e f u l i t a photos e n s i t i v e polymer. A unique P l a s t i c M a t r i x has been developed by Nippon P a i n t Co., u t i l i z i n g the p h o t o - s e n s i t i v i t y , the low s o f t e n i n g temperature and the good flow property o f 1, 2-PBD having 25% c r y s tallinity* An o r d i n a r y l e t t e r p r e s s p l a t e system i s shown i n t h i s schematic arrangement. ORIGINAL (Master P l a t e )

MATRIX

DUPLICATE

Metal Engraving Photopolymezr Plate

Plastic Matrix (Photocuring)

Plastic Printing Plate (Thermoplastic)

They wanted t o improve the system f o r reasons o f l a b o r h e a l t h c o n d i t i o n s and environment, and considered that the l e a d p r i n t i n g p l a t e should be changed t o an other p r i n t i n g p l a t e ( f o r example, polypropylene). Therefore, i t i s necessary f o r the improvement that the paper mache matrix i s changed to an other matrix by which any p r i n t i n g system could be produced. Some necessary c o n d i t i o n s o f the matrix are the r e a p p e r a n c i v i l i t y o f the r e l i e f images on the master p l a t e , and the t h e r m a l s t a b i l i t y when the r e l i e f images on the matrix are t r a n s c r i b e d to the p r i n t i n g p l a t e by press-molding. 1, 2-PBD having 25% c r y s t a l l i n i t y i s a good r e a p p e r a n c i v i l i t y o f the r e l i e f images on the master p l a t e , because o f i t s h i g h flow p r o p e r t i e s , but the thermal s t a b i l i t y o f 1, 2-PBD i s no good a t s o f t e n i n g temperature of polypropylene. C o n s i d e r i n g that the thermal deformation temperature o f c r o s s - l i n k i n g m a t e r i a l i s g e n e r a l l y i n c r e a s e d higher than t h a t o f non c r o s s - l i n k i n g m a t e r i a l , they s t u d i e d the improvement o f the thermal deformation temperature to c r o s s - l i n k only surface o f 1, 2-PBD. T h e i r d e s i r e d p l a s t i c matrix was comp l e t e d by photo-curing the surface o f 1, 2-PBD p l a t e with U.V. irradiation. Photograph IV shows t h a t the p l a s t i c matrix before U.V. i r r a d i a t i o n i s l i f t e d from the master p l a t e . The matrix i s impressed by a r o l l e r o r h y d r a u l i c p r e s s onto these p l a t e s a f t e r the preheated 1, 2-PBD p l a t e i s p l a c e d on the master p l a t e . Photograph V shows that the surface o f 1, 2-PBD matrix i s photocured by U.V. i r r a d i a t i o n . Photograph VI shows that the r e l i e f

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

3.

TAKEUCHI

ET AL.

l£-Polybutadiene

Photo IV. The plastic matrix (1,2-PBD) before UV irradiation is lifted from the master plate

Applications

Photo V. The surface of the plastic matrix is photo-cured by UV irradiation

Photo VI. The relief images on the photo-cured matrix are transcribed to the printing plate (PP plate)

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

33

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974. 4.9 2.8 8.0 2.2 0.75 0.20

Number of Leaves

Diameter of Stem (mm)

Weight of green plant (g) upper part lower part

Weight of dryed plant (g) upper part lower part

0.78 0.20

7.8 2.0

4.6 2.7

10.4

30

1.14

Soil A

0.84 0.25

8.7 2.8

3.2

5.0

12.8

150

5.70

Soil B

0.88 0.28

9.0 2.8

14.2 5.8 3.5

300

11.40

SoilC

Containing 1,2-PBD

Date of sowing: 5 October, 1971 Date of investigation: 15 November, 1971 Note (*) When the film is used as a mulch once a year, the above loading level is equivalent to that of 20 years. (by courtesy of Horticulture Department, Chiba University)

12.5

0

Equivalent quantity of degraded film fragments loaded per 10 ares of ground (depth of soil: 20cm volume of soil: 200m3) (kg)

Height of Plants (cm)

0

No 1,2-PBD content

E f f e c t s o f degraded 1, 2-polybutadiene fragments i n s o i l on the growth o f tomatoes

Loading level of degraded film fragments to the soil in a pot of 30cm diameter (about 7.51) (g)

Table 3-

0.83 0.28

8.5 3.0

6.0 3.0

13.8

450

17.10*

SoilD

3.

TAKEUCHI

ET AL.

1,2-Polybutadiene Applications

35

images on the photo-cured 1, 2-PBD matrix are t r a n s c r i b e d to the p r i n t i n g p l a t e by press-molding a t the s o f t e n i n g temperature o f polypropylene. Many p l a s t i c p r i n t i n g p l a t e s can be molded, u s i n g t h i s photo-curing matrix.

APPLICATION EXAMPLES AS A PHOTO-DEGRADABLE PLASTIC When exposed to the sun, the molded products o f 1, 2-PBD are changed t o e a s i l y crushable form, because o f the occurrence o f hardening d e t e r i o r a t i o n ( ^ ) . Consequently, the hard d e t e r i o r a t e d 1, 2-PBD f i l m s are e a s i l y fragmented with but l i t t l e force due t o photodegradation. When the f i l m i s used as a-mulching f i l m , c h a r a c t e r i s t i c s o f the photodegradable 1, 2-PBD compare to other photodegradable p l a s t i c s ( 5 ) which have l a t e l y been announced as f o l l o w s : 1)

Since 1, 2-PBD i s not p u l v e r i z e d i n t o powder a f t e r photodegradation, there i s no p o s s i b i l i t y o f secondary p o l l u t i o n by powdered dust.

2)

When mixed i n t o s o i l , the photodegraded 1, 2-PBD fragments give no adverse e f f e c t on v e g e t a t i o n and r a t h e r a c c e l e r a t e the growth o f p l a n t s by improving drainage and a e r a t i o n o f the s o i l (Table 3 ) •

3)

Since the photodegraded 1, 2-PBD i s not decomposed by numerous b a c t e r i a i n s o i l s o f Chiba, Japan, i t i s suggested t h a t there i s no r i s k o f high dimension pollutions.

However, the t e s t r e s u l t s propose many problems concerning i t s u t i l i z a t i o n . The p r a c t i c a l u t i l i t y as a photodegradable p l a s t i c should be c a r e f u l l y s t u d i e d to see what would be expected from

it.

CONCLUSION The New Thermoplastic S y n d i o t a c t i c 1, 2-PBD developed by JSR, has been discussed i n some a p p l i c a t i o n s , but the foregoings are s e v e r a l p a r t s o f our developed r e s u l t s . More d e t a i l e d des c r i p t i o n w i l l be given on another o c c a s i o n . JSR announced that the New Thermoplastic S y n d i o t a c t i c 1, 2PBD (JSR RB820 and JSR RB810) i s put on s a l e , a t the 18th o f June. We expect cooperation from a l l i n d u s t r i a l c i r c l e s f o r f u r t h e r development o f 1, 2-PBD u t i l i z a t i o n .

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

36

NEW

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ACKNOWLEDGEMENTS The authors would l i k e to thank Japan Synthetic Rubber Co., L t d . and Nippon P a i n t Co., L t d . f o r the permission t o p u b l i s h t h i s i n the symposium.

REFERENCE (1)

Y. Takeuchi, A. Sekimoto and M. Abe, T h i s symposium, 1974, 167th ACS Meeting, a t Los Angeles

(2)

S.P. Chen and J.D. F e r r y , Macromolecules 1,

(3)

F i r e s t o n e S y n t h e t i c Rubber & Latex Co., T e c h n i c a l b u l l e t i n

April,

270 (1968)

"FCR-1261" (4)

Y. Takeuchi and A. Sekimoto, Conference on " D e g r a d a b i l i t y o f Polymers and Plastics" 27, 28 Nov. 1973

(5)

G. S c o t t , P l a s t i c - R u b b e r - T e x t i l e , Sept., 361 (1970). Toronto Univ., Canada, C&EN, May 11, 61 (1970). M. Kato, 5 t h Conference f o r Reporting the R e s u l t s o f Polymer Research, Sept. 27, (1971).

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

4 K-Resin BDS Polymer: A New Clear ImpactResistant Polystyrene L . M . F O D O R , A. G . K I T C H E N , and C . C .

BIARD

Phillips Petroleum Co., Research and Development, Bartlesville, Okla.

Introduction In the third quarter of 1972 P h i l l i p s Petroleum Company started up a new plant to produce a new family of styrene plastics known as K-Resin BDS polymer. The initial plant capacity was 10 MM pounds per year but t h i s is presently being expanded. The resins are clear and tough and their moderate pricing places them between the low cost resins such as polystyrene,polyethylene and polypropylene which are either clear or tough (but not both) and high priced resins such as cellulosics, clear ABS and polycarbonate, which are both clear and tough. The exceptional c l a r i t y and impact resistance make them desirable replacements for conventional polystyrenes and other clear resins i n many applications(1). Applications thus far realized are i n toys, housewares storage units, l i d s , and a wide variety of packaging uses including b l i s t e r packs, injection molded tubs, bottles, and boxes having integral hinges. These resins are copolymers of styrene and butadiene prepared by a solution polymerization process. Presently two resins, which are designated KR01 and KR03, are produced. The primary difference between the two i s i n the molecular weight distribution, with the KR03 resin being the broader of the two. General Properties The general physical properties of these resins are shown i n Table I. It i s apparent that the two resins are quite similar i n properties except for hardness, impact strength and elongation. The KR03 resin i s clearly the tougher resin, having a dart drop impact strength of 163 in-lbs compared to 20 for the KR01 resin. Its elongation of 100$ i s approximately 10 times the value for the KR01 resin. However, the KR03 resin i s softer, having a Shore D hardness of 70 compared to 74 for the KR01 resin. These resins d i f f e r also i n molecular weight distribution 37 In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

38

NEW

INDUSTRIAL

POLYMERS

with the KR03 resin having a heterogeneity index of 2.1 compared to 1.3 for the KR01 resin. Typical gel permeation chromatograms are shown i n Figure 1. As would be expected, this difference i s reflected i n the flow properties of the resins relative to each other. This w i l l be discussed later with processability. TABLE I THE PROPERTIES OF K-RESIN POLYMERS

Properties Density, gm/cc Flow Rate, Cond. G, gm/10 min. Tensile Strength, .2"/m±n, p s i Elongation, .2"/miri, % Modulus of E l a s t i c i t y Flexural Modulus, p s i Flexural Yield Strength, p s i Heat Distortion Temp., 264 p s i Fiber Stress, °F Izod Impact, f t - l b s / i n notch (0.125" specimen thickness) Falling Dart Impact, in/lbs Hardness, Rockwell Hardness, Shore D Vicat Softening Point, °F Light Transmission, 100 mil, % Haze, 100 mil, % Refractive Index, d^5 GPC Molecular Weight M • n H.I. a

w

M

ASTM Test D792-66 D123S-65T D638-68

Resin Values KR01 KR03 1.01 1.04 8 6 4,000 4,000

D790-66 D790-66

240,000 6800

225,000 6800

D648-64T

168

160

D256-56

-

D785 D2240 D1525-65T D1746-62T D1746-62T

-

0.4 20 D75 74 200 90-95 1-5 1.5743

0.4 163 D72 70 200 90-95 1-5 1.5743

179,000 132,000 1.35

217,000 106,000 2.1

a - Measured on Waters Associates Model 100 with 10?, 10^, 103 A column array.

10^,

Appearance. Clarity and impact strength are the two properties which make these resins a valuable new development. The c l a r i t y , as measured by haze, i s as good or better than any of the competitive commercial resins, and these resins are colorless. Some competitive materials such as cellulosic and SAN frequently have a bluish or yellowish cast. Impact polystyrenes, on the other hand, are opaque. The haze of the commercial production thus far realized has been consistently near one per cent, which puts i t i n a class with general purpose polystyrene. Table II summarizes data on appearance.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

4.

FODOB

ET AL.

K-Resin BDS Polymer

39

KR01

KR03

DECREASING MOLECULAR WT. Figure 1.

Gel permeation chromatograms of k-resin BDS polymers

TABLE II A COMPARISON OF THE APPEARANCES OF VARIOUS RESINS Haze, % (ASTM D1746-62T)

Color

1-5 1-5

Water White Water White

2-3 Opaque Opaque

Water White White White

SAN

1.5

Yellowish

Cellulose Acetate

7.5

Resin K-Resin KR01 KR03

Polystyrene General Purpose Medium Impact High Impact

Bluish

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

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Impact Strength. The polymers are notch sensitive and, therefore, the conventional notched Izod test cannot be used to determine their ultimate impact strength. In fact, by that test the impact strength i s only comparable to general purpose polystyrene, but when measured by unnotched Izod or the f a l l i n g dart test, the resins are substantially above general purpose polystyrene. Table III compares the impact strength of these resins with that of some competitive resins. TABLE I I I A COMPARISON OF IMPACT STRENGTHS OF VARIOUS RESINS Izod Impact (ASTM D256-56)

Falling Dart

Falling Ball

Resin K-Resin KR01 KR03

0.4 0.4

Polystyrene General Purpose Medium Impact High Impact

0.3 0.9 2.5

SAN

0.3

3.6

Cellulose Acetate

2.8

37.5

20 163

0.2 16.0

0.1 0.7 3.7

1.8

10

In order to obtain the ultimate impact strengths of these resins, they require orientation. A study of the impact strength of injection molded bowls i l l u s t r a t e s t h i s very well. Bowls were injection molded from twelve different polymers and then the impact strength was measured on various parts of the bowls. The mold gate was i n the center of the bottom and was 0.213 inch i n diameter. The polymer flowed through the gate into the bottom, which was 0.080 inch thick, and then out into the side (wall), which was 0.052 inch thick. The polymer i n the walls was the most highly oriented, having flowed the farthest and having been sheared the most due to the ever decreasing thickness of the mold i n the direction of flow. Table IV shows the impact strength of the various bowl sections. I t i s clear that on the sprue (lowest orientation), the impact strength was the lowest and on the sides (highest orientation), the impact strength was the reatest. In fact, even the resins which gave very low values -16 12.7 3.1

5.2 5.0 6.1 4.7 6.4

1.8 1.3 1.2 1.2 0.74

5.0 5.2

0.58

-

Falling Dart Impact, In-Lbs Bottom Bottom on on Edge Sides Sprue

35 57 12

>80

80 75

32 160 50

2H Pass >32 160 57

Superior

Superior

Polyphenylene sulfide release coatings are finding applicat i o n i n coating cookware for non-stick use. Another interesting application for PPS release coatings involves the coating of t i r e molds to aid i n the release of the finished t i r e from the mold. (22) When t h i s release coating was employed, more than 8,000 t i r e s were produced without cleaning the mold; whereas, cleaning was required after producing only 500-600 t i r e s using a convent i o n a l silicone mold release agent. In addition the need for a blemish paint was eliminated, t i r e rejects were reduced and an improved surface f i n i s h resulted. Polyphenylene sulfide coatings are also finding acceptance as corrosion resistant, protective coatings for o i l f i e l d pipe, valves, f i t t i n g s , couplings, thermocouple wells and other equipment i n both the petroleum and chemical processing industries. Coated parts of t h i s type have been operating s a t i s f a c t o r i l y for extended periods of time i n media such as: l i q u i d ammonia, crude o i l , refined hydrocarbons, brine, dilute hydrochloric and s u l f u r i c acids, dilute caustic and many other chemicals. In particular, PPS i s providing protection when both corrosive environments and elevated temperatures are involved. Thus parts of carbon steel coated with PPS formulations are replacing parts previously fabricated from expensive alloy metals. Polyphenylene sulfide molding resins offer a combination of properties that include: good thermal s t a b i l i t y , outstanding chemical resistance, low coefficient of f r i c t i o n , useful elect r i c a l properties, and precision moldability. In turn, these properties lead to a variety of applications not available to many other plastics. For example, a number of pump manufacturers are using polyphenylene sulfide compounds as sliding vanes, impellers, impeller cases, gauge guards and seals i n corrosive service involving materials such as 60% sulfuric acid, l i q u i d ammonia and various hydrocarbons.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

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A N D HILL,

JR.

Polyphenylene Sulfide

95

Polyphenylene sulfide i s establishing i t s e l f as a basic engineering material f o r bearing applications and other types of a n t i - f r i c t i o n , low-wear uses. When solid lubricants such as molybdenum disulfide, polytetrafluoroethylene, etc., are incorporated, formulations with an interesting range of a n t i - f r i c t i o n characteristics result. An extremely low f r i c t i o n coefficient and low wear rate makes possible self-lubricated journal r o l l i n g element and sliding bearing components front these PPS formulations. The need for self-lubrication becomes extremely important i n those bearing applications where the bearing i s so inaccessible that proper servicing i s d i f f i c u l t or the bearing i s exposed to environmental extremes that make ordinary lubricants ineffective. A n t i - f r i c t i o n formulations containing PPS resin and three other available a n t i - f r i c t i o n compounds were evaluated i n journal bearing test configurations. Journal test bearings of the PPS formulation were compressio seats and then bored t bearing materials were machined into sleeve bearings from f l a t stock and press f i t t e d into steel spherical bearing seats. The test data recorded i n these evaluations included load, speed, PV (product of load, p s i ; and speed, fpm) wear, test duration, f r i c t i o n coefficient, and bearing temperature. (23) Table V shows a typical comparison of the test data recorded of the various a n t i - f r i c t i o n compounds at one shaft speed and one loading. Probably the most outstanding characteristic of the PPS formulation i s i t s extremely low f r i c t i o n coefficient. The effect of this very low f r i c t i o n coefficient i s clearly shown i n i t s extremely low bearing temperature build-up at various loads compared t o the other materials. Prevention of excessive bearing temperature i s most important i n achieving low wear rates, particularly i n plastic bearing systems where thermal conductivity i s usually low and dissipation of heat build-up i s not nearly as efficient as i n metal bearings. Temperature build-up can reach a c r i t i c a l temperature at which the cohesive strength of the plastic matrix i s so reduced that i t f a i l s as a binder f o r the self-lubricating additives and results i n excessive wear and bearing f a i l u r e . The wear for the PPS formulation i s r e l a t i v e l y low. Polyphenylene sulfide compounds with low f r i c t i o n and low wear properties have been evaluated as cages for non-lubricated b a l l bearings at 177°C (350°F) and 50 psi load. These materials have operated i n excess of 600 hours where other materials f a i l i n less than 20 hours. In another application a 10.5-inch diameter piston for a non-lubricated gas compressor has been i n service for over 6 months and i s performing better than the aluminum piston that i t replaced. The piston was machined from a 35-pound compression molded block of polyphenylene sulfide.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

0.0060 0.0025 0.0084 0.0078

Material Designation

PPS/tbS2/ 203 PTFE/MoS^/fiberglass PTFE/glass/iron oxide Polyimide/PTFE/graphite

162.5 125 117.5 55

Test Duration, hrs. 0.02-0.05 0.23-0.26 0.20-0.30 0.08-0.18

Friction Coefficient, μ 155 316 340 205

r

Maximum Bearing Temp. °F 500 277

f

Maximum Shaft Temp. °F

^Measurements made at 60 p s i load and 1800 revolutions/minute, corresponding to a PV of 17,640 (load i n p s i times speed i n feet/minute). Test shaft was 5/8" with a surface f i n i s h of 6-10 microinches, root mean square.

Sb

Radial Wear, in.

COMPARATIVE JOURNAL BEARING DATA»

TABLE V

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A N D HILL,

JR.

Polyphenylene Sulfide

97

West and Senior (24) have reported an evaluation of several polyphenylene sulfide compositions as journal bearings. The pre­ ferred composition was 25% polytetrafluoroethylene, 10% graphite, 10$ lead monoxide and 55% polyphenylene sulfide. This was com­ pared directly at various temperatures with a commercially a v a i l ­ able journal bearing lined with an epoxy composition. The epoxy bearing f a i l e d catastrophically at 170°C, but at that temperature the coefficient of f r i c t i o n of the polyphenylene sulfide bearing reached i t s minimum and the wear factor was s t i l l similar to that of polyimides at ambient temperature. The polyphenylene sulfide bearing was s t i l l stable at a temperature of 220°C. E l e c t r i c a l properties of polyphenylene sulfide compounds are summarized i n Table VI. The dielectric constant i s low i n com­ parison with other plastic materials. Similarly the dissipation factor i s low. Dielectric strength i s quite high ranging from 500-600 volts per mil fo f i l l e d and u n f i l l e d polyphenylen e l e c t r i c a l insulators. TABLE VI ELECTRICAL HJOFERTIES OF POLYHiENYLENE SULFIDE COMPOUNDS Unfilled PPS

Property

k0% Glassf i l l e d PPS

e

Dielectric constant, 25 C 103 Hertz lOlO Hertz

3.2 3.1

3.9 3.6

Dielectric constant, 120°C 1θ3 Hertz id Hertz

3.1 3.1

3.9 3.6

0.0004 0.004

0.0010 0.006

0.003 0.007

0.004 0.02

10

Dissipation factor, 25°C 1010 Hertz Dissipation factor, 120°C -

Dielectric strength, volts/mil

585

490

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

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The electric properties of polyphenylene sulfide and the a b i l i t y to injection mold very small parts with great precision have l e d t o the use of a variety of connectors, c o i l forms, etc., i n the electronics industry. For example, a pin cushion connec­ tor c o i l terminal support used i n color television i s now being volume produced from PPS i n a multiple unit. In conclusion i t can be said that polyphenylene sulfide i s unique by having high flexural modulus, resistance to solvents and chemical degradation, good e l e c t r i c a l insulating properties, a high melting point, yet with sufficient thermal s t a b i l i t y so that i t can be readily molded or applied by certain coating techniques. This l i s t of applications w i l l continue to grow as the design engineer becomes familiar with the properties and p o s s i b i l i t i e s that t h i s new plastic has to offer. Literature Cited 1. 2.

3. 4. 5. 6. 7. 8. 9. 10.

11. 12. 13. 14. 15. 16. 17.

Lenz, R. W., and Carrington, W. K., J . Polymer Sci., 41, 333 (1959). Gaylord, N. G., Polyethers, i n High Polymer Series, Vol. XIII, Part III, Interscience Publishers, New York, 1962, p. 3 1 . Smith, Η. Α., Encycl. Polym. S c i . Technol., 10, 653 (1969). Macallum, A. D., J. Org. Chem., 13, 154 (1948). Macallum, A. D., U. S. Patent 2,513,188 (June 27, 1950). Macallum, A. D., U. S. Patent 2,538,941 (Jan. 23, 1951). Smith, H. A., and Handlovits, C. E., ASD-TDR-62-372, Phenylene Sulfide Polymers, 1962. Lenz, R. W., and Handlovits, C. E., J . Polym. Sci., 43, 167 (1960). Lenz, R. W., Handlovits, C. E., and Smith, Η. Α., J. Polym. Sci., 5 8 , 351 (1962). Smith, Η. Α., and Handlovits, C. E., ASD-TDR-62-372, Report on Conference on High Temperature Polymer and F l u i d Research, Dayton, Ohio, 1962, p. 100. Smith, Η. Α., and Handlovits, C. E., ASD-TDR-62-322, Phenylene Sulfide Polymers, Part I I , 1962. Edmonds, J . T., J r . , and H i l l , H. W., Jr., U. S. Patent 3,354,129 t o P h i l l i p s Petroleum Co. (Nov. 21, 1967). Ray, G. C., and Frey, D. A., U. S. Patent 3,458,486 t o P h i l l i p s Petroleum Co. (July 29, 1969). Vidaurri, F. C., Jr., U. S. Patent 3,607,843 t o P h i l l i p s Petroleum Co. (Sept. 21, 1971). Tabor, B. J . , Magre, E. P., and Boon, J . , Eur. Polym. J . , 2, 1127 (1971). Short, J . N., and H i l l , H. W., Hr., ChemTech 2, 481 (1972). H i l l , H. W., J r . , and Edmonds, J . T., Jr., Polymerization Reactions and New Polymers, Advances i n Chem. Series, No. 129, ACS, 1973, p. 80.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

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A N D HILL,

JR.

Polyphenylene Sulfide

99

Brady, D. G., and Hill, H. W., J r . , Mod. Plastics, 51, No. 5, 60 (1974).

19. 20.

H i l l , H. W., J r . , Werkman, R. T., and Carrow, G. E., F i l l e r s and Reinforcements f o r Plastics. Advances in Chemistry Series, In Press. Ray, G. C., U. S. Patent 3,492,125 to P h i l l i p s Petroleum Co. (Jan. 27, 1970).

21. 22. 23. 24.

Tieszen, D. O., and Edmonds, J . T., U. S. Patent 3,622,376 to P h i l l i p s Petroleum Co. (Nov. 23, 1971). Plastics Design and Processing, 13, 76 (Sept. 1973). Tech. Service Memorandum No. 262 Plastics Div., P h i l l i p s Petroleum Co., Bartlesville, Oklahoma. West, G. H., and Senior, J . M., Tribology, 269, Dec. 1973.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

8 Polyimides: Chemistry, Processing, Properties S. L. KAPLAN* Cordova Chemical Division, Aerojet Chemical Co., Sacramento, Calif. 95813 S. S. HIRSCH Plastics & Additives Division, CIBA-GEIGY Corp., Ardsley, Ν. Y. High temperature polymer y molecules which r e t a i n u s e f u l p h y s i c a l p r o p e r t i e s f o r periods >10,000 hours a t 450°F or f o r >1,000 hours at 500-550 F. Stated a l t e r n a t e l y , these polymers perform satisfactorily at temperatures above the l i m i t s of epoxies or p h e n o l i c s : I m p l i c i t i n the d e s i g n a t i o n "high temperature" or "thermostable" polymer a r e two basic criteria: 1) thermo-oxidative stability - the ability to withstand degradation of p r o p e r t i e s over long periods at h i g h temperatures i n air. 2) thermophysical profile - specimen must r e t a i n a s u b s t a n t i a l percentage of room temperature s t r e n g t h and modulus a t elevated use temperature. P l a s t i c i t y or creep should not l i m i t the utility to temperatures below the thermo­ - o x i d a t i v e l i m i t , Workers new to the field, p a r t i c u l a r l y those w i t h chemical r a t h e r than engineering background, tend to emphasize the first c r i t e r i o n at risk of neglect to the second. I t is evident that both must be given weight, s i n c e e i t h e r can be utility limiting. Although the point will be s t r e s s e d l a t e r i n t h i s paper, it must be s t a t e d a t the outset that requirement f o r rigidity at 550°F n e c e s s i t a t e s chemical s t r u c t u r e s of chain s t i f f n e s s suffi­ c i e n t to p l a c e severe c o n s t r a i n t on achieving f a c i l e p r o c e s s ­ º

-ability. The S t r u c t u r e s

coo

αοο

To achieve the thermal performance j u s t described r e q u i r e s , g e n e r a l l y polymer chains possessing s e v e r a l fused r i n g s .

Fused r i n g s Non-fused c h a i n of r i n g s *Paper prepared when both authors were members of the CIBA-GEIGY 100

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

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101

Polyimides

Focusing a t t e n t i o n on the center member of the fused r i n g s t r u c t u r e , we see that four chemical bonds extend:

Thus, to b u i l d s t r u c t u r e s w i t h reasonable concentrations o f fused r i n g s , a t l e a s t one t e t r a f u n c t i o n a l monomer i s r e q u i r e d . Such m a t e r i a l s a r e g e n e r a l l y more c o s t l y than mono- o r d i f u n c t i o n a l compounds. Notable exceptions are those t e t r a f u n c t i o n a l m a t e r i a l s o b t a i n a b l e by o x i d a t i o n of methyl groups.

C

H

3 Y ^ Y

C

H

3

CH3

d e r i v a b l e from o-xylene

"

II

Compound (I) i s p y r o m e l l i t i c dianhydride (PMDA) and (II), X = j?, i s benzophenonetetracarboxylic

dianhydride

when

(BDTÀ).

Reaction of dianhydrides with diamines a f f o r d s polyamidea c i d s which, upon dehydration, g i v e polyimides.

Ο

\

0

0

(/

il

0

η

c - ^ - ? N - - c - - NH-

II

0

IV polyimide

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

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The s t r u c t u r e may be made more t r a c t a b l e by employment of BTDA r a t h e r than PMDA and/or use of a diamine of the type where X i s so chosen to provide greater molecular m o b i l i t y . Of a l l thermostable polymers, polyimides are the c o s t e f f e c t i v e candidates, due to combination of thermal s t a b i l i t y , p r o c e s s i n g c h a r a c t e r i s t i c s and, most p a r t i c u l a r l y , low cost ~ due to d e r i v a b i l i t y from the o n l y a v a i l a b l e inexpensive t e t r a f u n c t i o n ^ a l monomers. The P r o c e s s i n g Dilemma The i n i t i a l a p p l i c a t i o n s of polyimides were as varnishes and overcoat enamels a s i g n i f i c a n t improvemen as w e l l as e x c e l l e n t d i e l e c t r i c p r o p e r t i e s . They continue i n use today both as homopolymers and copolymers w i t h amides and e s t e r m o i e t i e s . P a r a l l e l i n g t h i s technology was the development by duPont o f Kapton® polyimide f i l m . Kapton enjoys a strong p o s i t i o n as a c l a s s 220+ organic f i l m . These a p p l i c a t i o n s represent the major p o r t i o n o f polyimide consumption. A p p l i c a t i o n s to engineering end uses have been slower to develop due to greater demands i n p r o c e s s i n g . The remainder of t h i s d i s c u s s i o n i s developed to such engineering a p p l i c a t i o n s t y p i f i e d by laminates, composites and molded a r t i c l e s . P r o c e s s i n g c o n s i d e r a t i o n s overshadow a l l others i n competi** t i o n f o r a t t e n t i o n by c u r r e n t workers i n t h i s f i e l d . Two key problems are at the root of the f r u s t r a t i o n . The f i r s t was a l l u d e d to e a r l i e r , namely that o f chain s t i f f n e s s , r e q u i r e d f o r s a t i s f a c t o r y thermophysical p r o f i l e and adequate s t a b i l i t y , p l a c e s a c o n s t r a i n t on p r o c e s s a b i l i t y . Engineers d e s i r e polyimide m a t e r i a l s which can be processed under low pressure at tempera^ tures between 350-400°F. T h i s i s mandated by autoclave procedures i n the i n d u s t r y which employ equipment, bagging m a t e r i a l s , t o o l ing, s e a l s and the l i k e designed f o r use w i t h epoxies and p h e n o l i c s . The problem i s r e a l , not merely the stubborn whim of a few possessing too much i n e r t i a f o r change, but n e c e s s i t y being the mother of i n v e n t i o n has provided f o r the development of improved bagging systems capable of higher temperatures. However the constant e f f o r t of polyimide s u p p l i e r s i s to p r o v i d e m a t e r i a l s which w i l l flow during f a b r i c a t i o n of p a r t s below 400 F, but which w i l l r e t a i n s t r u c t u r a l s t i f f n e s s i n use of that p a r t a t 550°F. The polymer chain s t i f f n e s s which a f f o r d s 550 F p h y s i c a l s wrecks havoc with 350-400°F p r o c e s s i n g . Even low molecular weight prepolymers which can b u i l d d u r i n g cure to higher molecular weight c r o s s l i n k e d s t r u c t u r e s o f t e n do not flow below 400°F unless a s p e c i e s i s chosen which s a c r i f i c e s 550°F thermophysical properties. e

e

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

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103

Polyimides

The second source of f r u s t r a t i o n stems from the condensation r e a c t i o n s employed to B u i l d macromolecular polyimides from p o l y amide-acide, prepolymers, or monomer mixtures. Condensation r e a c t i o n s e l i m i n a t e one s m a l l molecule (e.g. water, a l c o h o l , a c e t i c a c i d ) f o r every bond formed. Yet the great m a j o r i t y of p r a c t i c a l r e a c t i o n s l e a d i n g to s t a b l e r i n g s w i t h aromatic character are formed by condensation. T h i s means while imide formation i s t a k i n g p l a c e , v o l a t i l e s Cone mole per mole of r i n g formed - one mole of gas occupies 40 l i t e r s at 400 F) are e l i m i n a t e d . These gases g i v e r i s e to v o i d s i n the f a b r i c a t e d part which reduce d r a s t i c a l l y the p h y s i c a l p r o p e r t i e s o b t a i n a b l e and s a c r i f i c e thermo-oxidative s t a b i l i t y . More r e c e n t l y polyimides possessing s o l u b i l i t y i n t h e i r r i n g c l o s e d , i m i d i z e d , form have been made a v a i l a b l e , however, other polyimide c h a r a c t e r i s t i c s a r e compro^ mised and s h a l l be discussed i n more d e t a i l i n a l a t e r s e c t i o n . e

The S t a t e of the A r t The c o n s t r a i n t s upon p r o c e s s i n g d e s c r i b e d above have not been f u l l y r e s o l v e d , but progress has been made which permits employment of polyimides i n engineering composites, molded a r t i c l e s and to a very l i m i t e d extent, s t r u c t u r a l adhesives. The p r i n c i p a l avenues employed are discussed below. a) Compromise. F a c i l e p r o c e s s a b i l i t y can be r e a d i l y achieved by backing away from a l l aromatic c h a i n - s t i f f s t r u c t u r e s through i n c o r p o r a t i o n of a l i p h a t i c m o i e t i e s . E a r l y i n the development of h i g h temperature polymer s c i e n c e , these avenues were i n v e s t i g a t e d , but have been l a r g e l y d i s c a r d e d . The attendant s a c r i f i c e of thermo-oxidative s t a b i l i t y and thermophysical p r o f i l e pushes performance down to the p h e n o l i c s range, a c l a s s of polymer w i t h which polyimides cannot compete economically. b) P r o c e s s i n g under severe c o n d i t i o n s . Patents i s s u e d to duPont teach that the h i g h molecular weight r e a c t i o n product of o x y d i a n i l i n e and PMDA can be formed under severe c o n d i t i o n s of temperature and pressure i n t o c e r t a i n simple shapes. Products marketed under the trade-name Vespel are b e l i e v e d f a b r i c a t e d by such techniques. Complex a r t i c l e s are machined from the b a s i c shapes. Carborundum Co. has announced a v a i l a b i l i t y of a h i g h temperature aromatic p o l y e s t e r , Ekonol. T h i s m a t e r i a l , too, r e q u i r e s p r o c e s s i n g under c o n d i t i o n s deemed severe by conventional p l a s t i c s i n d u s t r y standards, although more processable v e r s i o n s have r e c e n t l y been i n t r o d u c e d . c) P r o c e s s i n g polyamide-acids vs polyimides ( s t a t e of the a r t ) . As s t a t e d e a r l i e r , the i n i t i a l r e a c t i o n product of a d i anhydride w i t h a diamine i s a polyamide-acid, o r d i n a r i l y s o l u b l e i n h i g h l y p o l a r s o l v e n t s such as dimethyl formamide (DMF) and N-methylpyrrolidone (NMP). Advantage may be taken of such s o l u t i o n s to f a b r i c a t e t h i n (non-engineering) items such as f i b e r s , f i l m s and wire-enamels. While polyimide f i b e r s are not

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104

INDUSTRIAL POLYMERS

commercial, f i l m (Kapton, duPont) and w i r e enamel (Pyre-ML,duPont) a r e . However, problems inherent to removing copious q u a n t i t i e s of solvent preclude e f f i c i e n t manufacture of laminated or molded a r t i c l e s v i a t h i s route. Prepregging, B-staging and laminating w i t h such v a r n i s h e s g e n e r a l l y gives d i s a p p o i n t i n g r e s u l t s due to l a c k of flow w i t h dry prepreg and s e r i o u s v o l a t i l e s problems w i t h wet. d) Approaches based on p r o c e s s i n g of monomers. (1) Patents issued to Monsanto Company teach that d i e s t e r s of BTDA can be mixed i n s o l u t i o n w i t h aromatic diamines to a f f o r d h i g h s o l i d s varnishes s t a b l e f o r long p e r i o d s . Reaction of the BTDA d i e s t e r w i t h diamine begins d u r i n g B-staging, but the r e s i n remains s u f f i c i e n t l y non-advanced to permit f a c i l e flow under m i l d vacuum bag-autoclave c o n d i t i o n s . However, v o l a t i l e s generated during completion of the r e a c t i o n can give r i s e to voids as d e s c r i b e d above. (2) A c y l a t e d QX-13, has been marketed by ICI of the u n i t e d Kingdom. T h i s composition i s reported^ to be a mixture of diacetylmethylened i a n i l i n e w i t h BTDA. Upon cure, a c e t i c a c i d i s l i b e r a t e d . Processing c o n d i t i o n s employed and p h y s i c a l p r o p e r t i e s obtained are g e n e r a l l y s i m i l a r to other condensation polyimide r e s i n s . (3) Polyaminobismaleimide r e s i n s . Patents issued to Rhone-Poulenc teach a novel approach to attainment of low temperature processing without v o l a t i l e s e v o l u t i o n . Commercial r e s i n s based on t h i s technology are d e s c r i b e d by M.A.J. M a l l e t 3 as mixtures of m e t h y l e n e d i a n i l i n e (MDA) w i t h the bismaleimide of m e t h y l e n e d i a n i l i n e c h a i n extend and c r o s s l i n k upon thermal t r e a t ment to a f f o r d e x c e l l e n t l y c o n s o l i d a t e d parts under modest p r o c e s s i n g c o n d i t i o n s . S t r i c t l y speaking, the thermal r e a c t i o n product of such a monomer mixture i s a polymaleimide, which s t r u c t u r e i s not f u l l y aromatic. This contrast with the fused r i n g aromatic polyimide s t r u c t u r e s described ( i l l u s t r a t e d on page 101.

polymale imid e (idealized structure) A c c o r d i n g l y , a p r i c e i s paid i n thermo-oxidative s t a b i l i t y to a t t a i n low temperature and pressure v o l a t i l e s - f r e e c u r i n g to composites of e x c e l l e n t i n i t i a l p h y s i c a l p r o p e r t i e s . (4) TRW/CIBA-GEIGY technology. Under contract from NASALewis, TRW Systems Group, developed an a d d i t i o n polyimide r e s i n

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

8.

KAPLAN

AND

fflRscH

105

Polyimides

named

P13N, P13N i s a t r u e polyamide-acid prepolymer of molecular weight 1300, end capped w i t h Nadic anhydride to permit a d d i t i o n cure, p r e c l u d i n g v o l a t i l e s e l i m i n a t i o n and v o i d formation. The v a r n i s h i s s u p p l i e d as a 40% s o l i d s s o l u t i o n i n DMF c o n t a i n i n g the f o l l o w ing i d e a l i z e d s p e c i e s 0 0 .

(V)

B-staging on the reinforcement can be c a r r i e d to f u l l i m i d i z a t i o n i f d e s i r e d to a f f o r d a n o n - v o l a t i l e s generating prepreg f o r use i n press molding ( V I ) .

I d e a l i z e d s t r u c t u r e of B-staged

P13N

Chain extension (curing) occurs between 475-575°F by a d d i t i o n r e a c t i o n s of the nadic end groups to a f f o r d a r t i c l e s of e x c e l l e n t thermal s t a b i l i t y and p h y s i c a l p r o p e r t i e s . Since the product i s predominantly aromatic polyimide, thermal s t a b i l i t y l i e s c l o s e to that obtained w i t h the a l l aromatic compositions and w e l l above polymaleimides. However, due to v o l a t i l e s - f r e e p r o c e s s i n g , p h y s i c a l p r o p e r t i e s , as w i t h the l a t t e r , are much e a s i e r to develop than w i t h condensation systems. P13N r e s i n i s an e x c e l l e n t base f o r the formulation of both p a r t i c u l a t e and r e i n f o r c e d molding compounds. Three avenues can be employed. 1) Dry b l e n d i n g of P13N powder (commercially a v a i l a b l e ) with fillers. 2) S l u r r y i n g of P13N v a r n i s h w i t h f i l l e r s , followed by d r y ing, B-staging and crushing, 3) Impregnation of a f i b e r tow with P13N v a r n i s h , followed by d r y i n g , B-staging and chopping. The polyimide molding compound prepared by any of the above techniques i s processed i n a preheated mold at 550-600°F, followed by post cure to 625°F f o r 2-8 hours f o r development of maximum p h y s i c a l p r o p e r t i e s . Absence of v o l a t i l e by-products permits f a c i l e production of sound moldings having t h i c k s e c t i o n s , while the modest (1300) molecular weight of the prepolymer permits flow at reasonable temperatures. P13N laminating v a r n i s h , while e x c e l l e n t l y s u i t e d f o r press l a m i n a t i n g , i s not recommended f o r autoclave laminate p r o c e s s i n g .

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

NEW

106

INDUSTRIAL

POLYMERS

G e l a t i o n , which s e t s i n at temperatures below that r e q u i r e d f o r f l o w a t slow heat-up r a t e s , does not permit c o n s o l i d a t i o n p r i o r to cure d u r i n g the gradual temperature r i s e of commercial autoc l a v e s ( c o n t r a s t press-molding i n which a press preheated to 550°F i s recommended). To overcome the l a c k of a u t o c l a v a b i l i t y of P13N laminating v a r n i s h both TRW and CIBA-GEIGY, who acquired technology r i g h t s i n 1970, have been working both j o i n t l y and independently to provide modified v e r s i o n s possessing the r e q u i s i t i v e flow. One system i s P105A. In t h i s v a r i a n t , 20% of the m e t h y l e n e d i a n i l i n e was replaced by t h i o d i a n i l i n e (TDA) and the molecular weight was dropped to 1050. In c o n t r a s t to P13N which demands r a p i d heat r i s e f o r p r o c e s s i n g , the modified r e s i n cures v i r t u a l l y independent of heat-up r a t e , values as low as l°F/minute being accepta b l e . F a c i l e a u t o c l a v a b i l i t y i s thus obtained, while the v o l a t i l e s f r e e cure of the p r o c e s s i n g at 550°F remains Such r e s i n s o f f e r s i m i l a r " f o r g i v e n e s s " i n molding a p p l i c a t i o n s . Requirement f o r employing a preheated mold to ensure r a p i d heat-up i s o b v i a t e d , and t r a n s f e r molding can be e a s i l y achieved. Studies employing the Brabender P l a s t i C o r d e r r e v e a l that P105A and developmental v a r i a n t s higher i n TDA content can be held i n the melt stage at e l e v a t e d temperatures upwards of one hour p r i o r to cure. Such performance suggests a v a r i e t y of impregnation and e x t r u s i o n a p p l i c a t i o n s , which processes a r e c u r r e n t l y under i n v e s t i g a t i o n . I t i s our o p i n i o n that p y r o l y t i c p o l y m e r i z a t i o n technology provides an optimum balance o f p r o c e s s a b i l i t y and property retention. 5) S o l u b l e p o l y i m i d e s . As p r e v i o u s l y mentioned most recent a c t i v i t i e s have centered about s o l u b l e p o l y i m i d e s . Though s o l u b i l i t y would not be expected w i t h polymers having a fused r i n g backbone, promise of s o l u b i l i t y was i n d i c a t e d by the p e c u l i a r p r o p e r t i e s of p o l y q u i n o x a l i n e s (VII) which have been shown to d i s p l a y a type of

Polyphenylquinoxaline

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

8.

KAPLAN

AND

HmscH

Polyimides

107

behavior which i s not possessed by compositions described p r e v i ously. Polymers such as VII demonstrate both s o l u b i l i t y and melt flow i n the f u l l y r i n g - c l o s e d form. Thus, p r o c e s s a b i l i t y can be achieved i n a wholly aromatic system f r e e of complications from reaction v o l a t i l e s . To be sure, to o b t a i n a thermophysical p r o f i l e i n the range of Skybond or P13N systems r e q u i r e s choice of a s t r u c t u r e w i t h very high "Tg" (>600°F), and t h i s r e s u l t s i n very high p r o c e s s i n g temperatures. Nonetheless, i t i s p o s s i b l e to o b t a i n sound, v o i d - f r e e laminates and moldings employing these techniques, u n f o r t u n a t e l y , the t e t r a f u n c t i o n a l monomers r e q u i r e d are c o s t l y . However, there are r e p o r t s that one of these, d i aminobenzidine (DAB) may become a v a i l a b l e at reasonable cost due to p o t e n t i a l volume use i n polybenzimidazole f i b e r s f o r the A i r Force. The i n d i c a t i o n that f u l l y aromatic polyimides could e x i s t with both flow and s o l u b i l i t the Russian s c i e n t i s t , Korshak based upon a n i l i n e p h t h a l e i n (VIII) and BTDA.

Unfortunately, thermal s t a b i l i t y of t h i s system was modest. During the past two years, there has been c o n s i d e r a b l e a c t i v i t y with s o l u b l e polyimides, the Upjohn Company o f f e r i n g s e v e r a l candidates commercially, while both CIBA-GEIGY and duPont revealed developmental compositions. Patent l i t e r a t u r e i n d i c a t e s r e l a t e d a c t i v i t y i n Japan and Germany as w e l l . High molecular weight s o l u b l e polyimides are indeed " p o l y q u i n o x a l i n e - l i k e i n t h e i r p h y s i c a l p r o p e r t i e s . Unfortunately the complete e l i m i n a t i o n of solvent i n molding powders and prepreg was not e a s i l y achieved i n our l a b o r a t o r i e s and thus, the formation of v o i d f r e e f u n c t i o n a l a r t i c l e s has proven d i f f i c u l t . A l s o t h e i r requirement f o r high processing temperatures and somewhat diminished thermophysical p r o f i l e i s expected to l i m i t commercial acceptance i n t o engineering end uses. M

P r o p e r t i e s and A p p l i c a t i o n s Composite S t r u c t u r e s . Polyimides' have been u t i l i z e d f o r the f a b r i c a t i o n of composites of quartz, g l a s s , boron, g r a p h i t e and

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

108

NEW INDUSTRIAL POLYMERS

Room Temp.

F l e x u r a l ST

2.45 χ 1 0 p s i

F l e x u r a l Hod.

2.49 χ 1 0

SBS.

13,100 p s i

GLASS

GRAPHITE

BOR ON Press Molded

Room Temp.

a

600 F

Room Temp.

600'F

600°F

HM-S s

7

psi

0.91 χ 1 0 p s i

2.70 χ 1 0 p s i

7

2.20 χ 1 0

9,3000 p s i

6,100 p s i

s

psi

1.54 χ 1 0 p s i

2.02 x 1 0

7

psi

10.400 p x i HT-S

s

5

2.48 χ 1 0

2.20 χ 1 0

5

psi

psi

3

50-65 χ 1 0 p s i 6

3.5-4.0 χ l O ^ s i 2.8-3.0 χ 1 0 p s i 8,000 p s i

3200-3500 p s i

1.12 χ 1 0 p s i 5

2.3 χ 1 0 p s i

2.10 χ 1 0

13,800 p s i

7,700 p s i

7

7

3

80-90 χ 1 0 p s i

7

psi

Autoclave Molded F l e x u r a l ST

2.45 χ 1 0

psi

2.22 χ 1 0

5

psi

F l e x u r a l Mod.

2.20 χ 1 0 p s i

1.90 χ 1 0

7

psi

SBS.

5

7

HT-S

5

2.00 χ 1 0

5

psi

1.36 χ 1 0 p s i

1.40 χ 1 0

7

psi

1.33 χ 1 0

7

psi

psi

1.55 χ 1 0

s

psi

11,225 p s i

10,500 p s i

2ype

Figure 1.

A

2.26 χ 1 0

s

Physical properties

80 Flexural Strength at Test Temperature, psi χ 10

0

I

-3

Flexural Modulus at Test Temperature, psi x10- 0

0 200 400 Hours Aging at Test Temperature

6

600

800

1000

Figure 2. Typical flexural properties of Ε glass reinforced P13N laminates as a function of aging in air at elevated temperatures

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

8.

KAPLAN

ι

ι

ι

109

Polyimides

A N D HIRSCH

1

1

1

1 1

120 -Percent of 550 F Properties Retained After Heat Aging ral mo dulus Flexi Ifiterlarr inarsh e a r *

80 60

Flexur al strer igth

1

40 20 0 0 100 200 :300 Hours, Aging at550 F

*WO

500

600

700

800

900

Figure 3. Flexural strength, flexural modulus, and short beam shear at 550°F of non-post cured P13N/boron speci­ mens after aging at 550°F

Specific Gravity, o/cc Hardness, Shore D Flexural Strength, pal 25C(77F) 260 C (500 F) 288 C (550 F) Flexural Modulus, pal χ 10· 25 C (77 F) 280 C (500 F) 288 C (550 F) Tensile Strength, pal 25C(77F) 260 C (500 F) Tensile Modulus, pal χ 10* 25C(77F) 260 C (500 F) Elongation at Failure, % 25C(77F) 260 C (500 F) Compressive Strength, pal 25C(77F) 260 C (500 F) Compressive Modulus, pal χ 10* 25 C (77 F) 260 C (500F) Compressive Strain at Failure, % 25C(77F) 260 C (500 F ) Deflection Temperature Before Post cure After Post cure Heat Resistance, Aged, % Weight Loss 100 hours 250 hours 500 hours 750 hours Coefficient of Linear Thermal Expansion la/hWCal25Cto22SC Water Absorption, immersion at 24 hours 7 days Molded Shrinkage (In /In ) Specific Heat, cal/°C/gm Thermal Conductivity BTU-ln /hr -ft '-°F FlammaMllty, Limited Oxygen Index

Figure 4.

ASTM Test Method

Value

Property

D-792. Method A D-790 O-790

1.33 90.5-91.5 10,000-12.000 6.000-8,000 5,000-6.000

D-790

4.6-4.9 3.0-3.3 2.8-3.0

D-657

7.260 5.700

D-657

5.56 3.46

D-657

1.37 1.82

D-695

37.000

—

D-695

4.19

—

D-695

14-17

— >300C >300C 316 C (600 F) 2.3 3.7 6.8 8.2 2.3X10"

D-648 288 C (550 F) 14 1.2 2.5 2.5

5

23 C 0.4% 1.3% 1.26x10"* 0.267 1.56 31.6

100C 1.9% -

D-696 D-510 D-256 Cenco-Fitch D-2863-70

Physical data for P13N polyimide molding powder

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

N E W INDUSTRIAL

110

Figure 5.

Summary of typical properties (machined and direct formed parts)* * SP-I

PROPERTY MECHANICAL Tente Sttngth lui tirait») lata

Etoapoisn (uttimm)

Fltxural Strwtth (dtimttl Rtkwàl Stnin (uliîtrau) Fhxunl Uodotia CftmsnnsiM Stftnjth lisHimsl

ELECTRICAL DWKtric ConfiKtit 10* Hi Οίηριϋοη Fmetwit 10* Hi OWsctric Suuigtli — short tins 80 mill thitkntss Volume Reuitlvity Svfasi Rniitlvily ArcftBriBtnca WEAR AND FRICTION Mtar Ritt (unhitwlmiil) miritraftnPV- 2SJ0Q0) m« (PV- 25500)

POLYMERS

Tf*P. 13 572 73 572 73 572 73 572 73 572 73 572 73 572 73 572 73 572

tt— I1II>

ASTM

ΜΙ·

01708

psi 110*

01708

%

01708

ail* !0

0730

tei« 10

0780

%

07»

tail 10

0695

edilO*

us 65 10 465 300 185 105

BJO

3

a

12.Î

s

4J 460 275 3BJ* 185·

069S

%

>§ο·

0695

ssix 10*

>60· 569 276

73 S06 73 SOS

DIM

73 73

02S7 02S7 049S

o-%r

It J 4J BJO 25 «50 275 1SJ 8.4

ms

m

8J

4.1 440 260 455* 195" >6Θ· >50· 615 235

65 360 I1J0

420 18.7

DU PONT POLY MIDE COMPOST) ION SP-21 SP-22 115% Onphlta) H i MO D-li M i Mil » 1 i H i 115 65 45 3J 650 450 HJO 93 7.t 4J0 670 350 285 95 33J0 14J0 630 300

95

65 4.4 2J0 15 540 365 11.4 65 35 2.4 505 308 345 95 385 135 640 290

45 470 75 25 480 17.4

3.41

750

10'*-10"

5«t0 I

9.7 45 25 15 790 440 1S.4 75 35 15 900 660 18.2 105 175 115 600 360

55 75 25 15 25 05 620 720 310 95 55 2.1 15 630 385 185 105 185 11.4 600 430

sr-31 Ml

WHtaSffliiii!

D-li

Ml

145 75 9.4 65 S45 315 225

95 65 45 35 440 305 165

12.0

65

85

6.1

15

1.6

534

495

1000

620

105

7.1

55

05

3.7 05

1360

995

0160 0149

«Oitt/fflf l

ιο·*-ιο·· 230 int/IQOOhn.

J01U-U15

504 59

56

55 56

NOTES: (a) M designates specimens machined from molded billets, l a n d || denote direction of specimen orientation relative to direction of molding (perpendicular and parallel respectively). Most values for polyimide parts produced from rod and tube forms are between the M l and M|| values. (b) D-1 designates direct-formed specimens measured only in thel direction due to thickness limitations. Direct-formed parts have a fractional percentage of T E F L O N T F E fluorocarbon resin added to facilitate processing. ( *) For SP-1, these are compressive stresses at 50% strain, not ultimate strengths. Specimens did not fail. **Du Pont V e s p e l Design Handbook A 72582

PRD-49. The two p r i n c i p a l a p p l i c a t i o n s of today are j e t engine n o i s e suppression devices and radomes f o r supersonic a i r c r a f t . These a p p l i c a t i o n s employ polyimides e x c e l l e n t property r e t e n t i o n at elevated temperature and long term o x i d a t i v e s t a b i l i t y . In the radome a p p l i c a t i o n use i s a l s o made of t h e i r e x c e l l e n t d i e l e c t r i c p r o p e r t i e s and the d e s i r a b l e f l a t p r o f i l e of these p r o p e r t i e s versus temperature. More r e c e n t l y polyimides a r e a t t r a c t i n g a t t e n t i o n i n combi­ n a t i o n with g r a p h i t e f i b e r ; l e s s the r e s u l t o f the h i g h tempera­ t u r e p r o p e r t i e s than i n s e n s i t i v i t y to moisture. Experience* has shown the d e t e r i o r a t i o n of conventional composites during ambient storage to be the r e s u l t o f a b s o r p t i o n of moisture. The i n ­ f i l t r a t e d water apparently p l a s t i c i z e s conventional matrices causing s i g n i f i c a n t d e t e r i o r a t i o n of elevated temperature (300°F or higher) s t r e n g t h . The i n s e n s i t i v i t y o f polyimides^ t o moisture and t h e i r e x t r a margin of thermal performance ( t o 600°F) has made t h e i r p o t e n t i a l u t i l i t y a t t r a c t i v e . T y p i c a l p r o p e r t i e s of these engineering laminates a r e presented i n F i g u r e s 2 and 3.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

8.

K A P L A N A N D HIRSCH

Polyimides

111

A second area of p o t e n t i a l and perhaps the l a r g e s t i s molding compounds. A p p l i c a t i o n s a r e v i r t u a l l y u n l i m i t e d s i n c e almost any property achieved with c o n v e n t i o n a l molding compounds such as phenolic and epoxy can be r e a l i z e d w i t h the polyimides, accompai e d by extension of the d e s i r e d p r o p e r t i e s to 550°-600°F. Required i s i d e n t i f i c a t i o n of those a p p l i c a t i o n s which r e q u i r e the temperature c a p a b i l i t y ; a l b e i t cost e f f e c t i v e n e s s i s the prime c o n s i d e r a t i o n . I t i s d i f f i c u l t to do j u s t i c e to the myriad of matrix/reinforcement combinations; a c c o r d i n g l y , p r o p e r t i e s o b t a i n a b l e a r e summarized i n F i g u r e s 4 and 5. Literature Cited 1.

De Brunner, R. E. and F i n c k e , J. K., U. S. Patent 3,423,366.

2.

Dixon, D. R., George Polyimide, 26th Annua D i v . 19-E (1971).

3.

M a l l e t , M.A.J., Polyaminobismaleimide Resins, Modern P l a s t i c s , June 1973 ppg. 78-81.

4.

Hertz, J . , Moisture E f f e c t s on the High Temperature Strength of F i b e r - R e i n f o r c e d Resin Composites, 4th N a t i o n a l SAMPE Conference, Palo A l t o , Calif. Oct. 1972.

5.

P a l l a d i n o , W. J . , Kaplan, S. L., and Villani, T. J., Engineer­ i n g w i t h Polyimides - P a r t I I , 5 t h N a t i o n a l SAMPE Conference, Kiamesha Lake, Ν. Υ., October 1973.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

9 Polyaminobismaleimides M . A. J.

MALLET

Rhone-Poulenc, Paris, France F. P.

DARMORY

Rhodia Inc., New York, Ν. Y.

1.

Introduction

Polyimide resins constitute a family of plastics p o s s e s s e d o f d r a m a t i c a l l y s u p e r i o r p r o p e r t i e s when compared t o more c o n v e n t i o n a l plastics. Of particular importance is their ability t o m a i n t a i n u s e f u l me­ c h a n i c a l properties after extreme t h e r m a l exposures for p r o l o n g e d p e r i o d s o f t i m e . The g e n e s i s o f this attribute is t w o - f o l d -—the h i g h l y a r o m a t i c n a t u r e o f t h e polymer backbone, which c o n f e r s t h e h e a t stability, and t h e imide moiety, which i m p a r t s stiffness t o the macromolecular c h a i n . The facile o x i d a t i o n a t ele­ v a t e d temperature o f aliphatic polymer systems and t h e n e c e s s i t y for f u s e d r i n g s t o a c h i e v e h i g h r e s i n glass transition temperatures and concomitant e l e ­ v a t e d temperature polymer m e c h a n i c a l s a r e w e l l r e c o g n i z e d and amply documented. Two f u n d a m e n t a l l y different approaches t o t h e m o l e c u l a r a r c h i t e c t u r e o f p o l y i m i d e s can be employed: The historically-first s y n t h e t i c method c o n s i s t s in c o n s t r u c t i n g tractable, h i g h m o l e c u l a r weight p r e ­ c u r s o r s , called p o l y a m i c a c i d s , which a r e i m i d i z e d d u r i n g t h e c u r e c y c l e , w i t h l o s s o f water, t o t h e intractable, insoluble, infusible condensation polyimides. - The more r e c e n t s y n t h e t i c r o u t e p r e i m i d i z e s s h o r t m o l e c u l a r segments, similar i n n a t u r e t o t h o s e o f c o n d e n s a t i o n p o l y i m i d e s . Cure is by p o l y m e r i z a t i o n

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o f t h e r e a c t i v e t e r m i n i o f t h e "prepolymers" w i t h o u t loss of volatiles. These a r e t h e a d d i t i o n p o l y i m i d e s . W h i l e c o n d e n s a t i o n p o l y i m i d e s a f f o r d t h e most heat s t a b l e polymers, they a r e g e n e r a l l y d i f f i c u l t and e x p e n s i v e t o p r o c e s s and a f f o r d v o i d y p a r t s . Epitomical o f the heat r e s i s t a n c e p r o p e r t i e s o f c o n d e n s a t i o n p o l y i m i d e s a r e t h e 20,000+ and 9,000 h o u r s e r v i c e l i v e s o f NOLIMID A380 a d h e s i v e f o r t i t a n i u m bonds a t t e m p e r a t u r e s o f 500° and 575°F, respectively. By c o n t r a s t , a d d i t i o n p o l y i m i d e s a l l o w t h e r e p r o d u c i b l e and f a c i l e p r e p a r a t i o n o f l a r g e and void-free parts a a r t i c l e thermal s t a b i l i t y (PABM's) a r e members o f t h e a d d i t i v e p o l y i m i d e c l a s s of resins. 2.

Polvaminobismaleimide Chemistry

M u l t i t u d e s o f r e s e a r c h e r s have i n v e s t i g a t e d t h e h i g h r e a c t i v i t y o f t h e a c t i v a t e d d o u b l e bonds o f b i s m a l e i m i d e s , as shown below.

M a l e i m i d e d o u b l e bonds can r e a c t b y e i t h e r homolytic or h e t e r o l y t i c s c i s s i o n . I n t h e former c a s e , h o m o p o l y m e r i z a t i o n w i t h a second maleimide group i s observed? i n t h e l a t t e r event, n u c l e o p h i l i c addition i s possible.

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I r r a d i a t i o n at 240°C, and at reduced pressure, o f 1,4-dimaleimidobenzene affords 50% y i e l d s o f polybismaleimides, which remain unaffected by temperatures as high as 600°C (Ivanov? Russian Patent #164,678). S i m i l a r l y , heating o f 4,4 -dimaleimidodiphenylmethane affords polymers which are heat stable to 460°C. These i n f u s i b l e and i n t r a c t a b l e products s u f f e r from extreme b r i t t l e n e s s , which severely r e s t r i c t s t h e i r p r a c t i c a l u t i l i t y (Sambeth & Grundschober; French Patent #1,455,514). Working i n the area o f elastomers, Kovacic (U. S. Patent #2,818,407? Dec. 31, 1957) reported the Michael addition o f amine capped prepolymers to b i s maleimides. S i m i l a r l y found that r e a c t i o maleimides and primary aromatic diamines i n r e f l u x i n g ethanol afforded polymers, which thermally degraded so r a p i d l y that they could not be considered heat resistant. Recent work i n Rhone-Poulenc* s laboratories, summarized i n U. S. Patent #3,562,223 (July 13, 1967), has shown that by j u d i c i o u s s e l e c t i o n o f a b i s maleimide t o aromatic diamine r a t i o between these two r e a c t i o n extremes, i t has proven p o s s i b l e to develop a c l a s s o f polyimide r e s i n s with outstanding physicals and c o n t r o l l e d c r o s s l i n k density. (Figure 1). While side-reactions o f the primary aromatic amine with the maleimide moiety were to be feared, none are i n f a c t observed. Thus, N-butylamine amminolyzes succinimides r e a d i l y i n a modification of the time-honored (1887) Gabriel synthesis o f amino acids? by contrast, a n i l i n e does not react with succinimides, even i n hot DMF. This contrast i n behavior between primary a l i p h a t i c and aromatic amines i s ascribàble to t h e i r v a s t l y d i f f e r e n t b a s i c i t i e s (pK^'s of 3.3 and 9.3, r e s p e c t i v e l y ) . F i n a l l y , maleimides are t r a d i t i o n a l l y prepared by a two-step synthesis (e. g. Searle? U. S. Patent #2,444,536? May 14, 1946). Reaction o f maleic anhydride with an amine at room temperature, i n e i t h e r NMP, DMF or acetone, affords the intermediate maleamic acid, which i s then cyclodehydrated by a c e t i c anhydride at 60°C i n DMF. ,

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3.

Polvaminobismaleimide P r o p e r t i e s

The t h e r m a l r e s i s t a n c e o f p o l y a m i n o b i s m a l e i m i d e s may b e e v a l u a t e d b y t h r e e c r i t e r i a — thermogravim e t r i c a n a l y s i s , t h e r m o p h y s i c a l p r o f i l e , and thermooxidative r e s i s t a n c e . 3.1 Thermocrravimetric A n a l y s i s . F i g u r e 2 shows t h e TGA c u r v e s o b t a i n e d f o r PABM s d e r i v e d from m e t h y l e n e d i a n i l i n e and o x y d i a n i l i n e under a i r and n i t r o g e n atmospheres. I n b o t h c a s e s , scan r a t e s o f 20°F/min were employed. These c u r v e s r e v e a l t h a t : 1

t h e TGA main b r e a k p o i n t , under e i t h e r a i r o r n i t r o g e n , i s 360°C f o r MDA-derived PABM s and 290°C f o r ODA-derived PABM s? u n t i l 500°C, c u r v e s o b t a i n e d i n a i r and n i t r o g e n are i d e n t i c a l ; c h a r y i e l d i s c a . 4 7 % f o r b o t h PABM systems. 1

1

The c o n c l u s i o n t o b e drawn from t h i s i n f o r m a t i o n i s t h a t ODA o r MDA b a s e d PABM s behave almost i d e n ­ t i c a l l y on t h e r m a l exposure. This i s not t o t a l l y unexpected, a s t h e dominant f a c t o r , o r a l t e r n a t i v e l y t h e weak l i n k , i n o x i d a t i v e d e g r a t i o n o f t h e s e 1

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M A L L E T AND DARMORY

polymers i s t h e a l i p h a t i c prepolymer t e r m i n i , are i d e n t i c a l f o r b o t h r e s i n s .

which

3.2 T h e r m o p h y s i c a l P r o f i l e . T y p i c a l 181 E - g l a s s (A-1100 f i n i s h ) PABM l a m i n a t e m e c h a n i c a l s a r e shown i n T a b l e I . Room temperature f l e x u r a l s t r e n g t h and modulus a r e 70,000 p s i and 4,000,000 p s i , r e s p e c t i v e l y . These l a m i n a t e s r e t a i n 70% and 80%, r e s p e c t i v e l y o f t h e i r room temperature f l e x u r a l s t r e n g t h and modulus at 480°P. To a l l o w a more m e a n i n g f u l comparison o f PABM* s w i t h c o m p e t i t i v e r e s i n systems, t y p i c a l room temper a t u r e , 400°F, and 480°F l a m i n a t e f l e x u r a l s t r e n g t h s are t a b u l a t e d below t h e s i s represent th properties. F l e x u r a l Strength a t :

PABM EPOXY NOVOLAC EPOXY SILICONE

R.T.

400OF

480°F

70 70 80 37

60 32 20 20

50 20 15 18

KSI KSI KSI KSI

KSI (85%) KSI (45%) KSI (25%) KSI (55%)

KSI (70%) KSI (30%) KSI (20%) KSI (50%)

3.3 T h e r m o o x i d a t i v e S t a b i l i t y . F i g u r e s 3-6 d e t a i l t h e r e t e n t i o n o f PABM l a m i n a t e (A-1100 f i n i s h ) f l e x u r a l s t r e n g t h and modulus a f t e r extended a g i n g p e r i o d s a t temperature v a r y i n g from 355° t o 480°F. 85% o f i n i t i a l f l e x u r a l s t r e n g t h ( e i t h e r room o r e l e v a t e d temperature) i s m a i n t a i n e d a f t e r 10,000 h o u r s o f a g i n g a t 355°F. U s i n g as l a m i n a t e h a l f - l i f e c r i t e r i o n , 50% r e t e n t i o n o f i n i t i a l f l e x u r a l s t r e n g t h , the f o l l o w i n g v a l u e s a r e o b t a i n e d f o r PABM s : 1

-

10,000 h o u r s a t 400°F? and 4,000 h o u r s a t 480°F (CS-290 f i n i s h ) . Comparable 480°F h a l f - l i f e v a l u e s a r e : 2,000 h o u r s f o r F r e i d e l - C r a f t s p h e n o l i c r e s i n s ( s o u r c e : A l b r i g h t and W i l s o n ) ? and 250 h o u r s f o r u n m o d i f i e d p h e n o l i c r e s i n s .

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ΡABM/181 Ε-Glass Laminate P h y s i c a l s

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Figure 3. Changes in flexural strength during thermal aging at 355°, 390°, and 430°F (180°, 200°, and 220°C)

Figure 4. Changes in flexural strength during thermal aging at 355°, 390°, and 430°F (180°, 200°, and 220°C)

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Figure 5.

Figure 6.

Changes in flexural strength during thermal aging at 480°F (250°C)

Changes in flexural modulus during thermal aging at 480°F (250°C)

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Polyaminobismaleimide P r o c e s s i n g

Commercial v a r i a n t s o f p o l y a m i n o b i s m a l e i m i d e r e s i n s have been f o r m u l a t e d t o p r o c e s s s i m i l a r l y t o c o n v e n t i o n a l p h e n o l i c s , e p o x i e s , and p o l y e s t e r s . C o n s t i t u e n t monomers o f t h e f o r m u l a t i o n a r e B-staged t o a degree o f advancement such t h a t c l a s s i c a l r h e o l o g i c a l s t u d i e s on PABM s y i e l d Brabender P l a s t i c o r d e r c u r v e s whose shape i s r e m i n i s c e n t o f t h o s e of phenolics. To f u r t h e r q u a n t i f y t h e s e statements, l e t us n o t e t h a t PABM s have m e l t i n g p o i n t s o f 100-120°C and g e l t i m e s which a r e v e r y temperature dependent Viscosity i n c r e a s e s from 10 150°C and i n 5 min. a t 170°C! In p r a c t i c e , p o l y a m i n o b i s m a l e i m i d e p a r t s a r e p r o c e s s e d on c o n v e n t i o n a l thermoset t r a n s f o r m a t i o n equipment (compression, t r a n s f e r , and i n j e c t i o n molding) a t 350-400°F, i n 5-20 minute c y c l e s , and a t 3,000-15,000 p s i . 1

1

5.

Summary

The p o l y a m i n o b i s m a l e i m i d e r e s i n s we have reviewed e x h i b i t many i n t e r e s t i n g a t t r i b u t e s . these are t h e i r : -

-

Among

r h e o l o g y , comparable t o t h a t o f c l a s s i c a l thermosetting resins? m o l d a b i l i t y a t modest temperatures, i n c o n v e n t i o n a l p r e s s e s , and a t low c o s t ? mechanical p r o p e r t i e s , superior t o those o f s e v e r a l m e t a l s on a w e i g h t b a s i s ? e x c e l l e n t dimensional s t a b i l i t y ? f i r e , r a d i a t i o n , c r y o g e n i c temperature, and s o l v e n t resistance? u t i l i t y i n e l e c t r i c a l , f r i c t i o n , and a b l a t i v e applications.

Taken as a whole, t h e s e f a c t o r s suggest t h a t PABM's w i l l f i l l many 500°P a p p l i c a t i o n s i n t h e a i r c r a f t , a i r compressor, aerospace, automotive, b e a r i n g s , e l e c t r o n i c , e l e c t r i c a l , and n u c l e a r i n d u s t r i e s .

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

10 Processable Polyimides F. P.

DARMORY

Rhodia Inc., New York, Ν. Y.

1.

Introduction

S i n c e t h e d i s c o v e r y o f p o l y i m i d e s in t h e e a r l y 1960's e n g i n e e r s have sought t o p r e p a r e composite p a r t s where maximum use c o u l d be made o f their e x c i ­ ting p r o p e r t i e s . Typical attributes include: high h e a t r e s i s t a n c e (500° F and up), good m e c h a n i c a l p r o ­ perties, wear r e s i s t a n c e , low friction, chemical i n e r t n e s s , low o u t g a s s i n g , radiation and c r y o g e n i c temperature stability, and i n h e r e n t n o n - f l a m m a b i l i t y . These attempts were f r e q u e n t l y thwarted, however, b y d i s c o u r a g i n g resin processability. Indeed, e x t e n s i v e and complex c u r e and p o s t - b a k e c y c l e s were r e q u i r e d and strict adherence t o fabrication p a r a m e t e r s was demanded. The historically-first condensation polyimides have r e c e n t l y been complemented b y a second c l a s s o f resins - addition-type polyimides. KINEL compounds and KERIMID 601 l a m i n a t i n g resin are members o f t h i s new f a m i l y of p o l y i m i d e s . Chemically they are d e s i g nated polyaminobismaleimides (PABMs) · C o n d e n s a t i o n p o l y i m i d e s a r e p r e d i c a t e d on t h e r e a c t i o n o f an a r o m a t i c d i a m i n e w i t h an a r o m a t i c dianhydride. The r e s u l t a n t , t r a c t a b l e p o l y a m i c a c i d is c o n v e r t e d d u r i n g c u r e t o t h e infusible, insoluble and i n t r a c t a b l e p o l y i m i d e w i t h l o s s o f w a t e r . A d d i t i o n p o l y i m i d e s are b a s e d on s h o r t , p r e i m i d i z e d segments v e r y similar in n a t u r e t o t h o s e o f c o n d e n s a t i o n p o l y i m i d e s . These segments a r e capped by t e r m i n i which polymerize t h e r m a l l y without l o s e

124

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of v o l a t i l e s . Processing i s simple; only a s l i g h t s a c r i f i c e , as compared to condensation polyimides, i s noted i n cured matrix thermal s t a b i l i t y . The minor decrease i n PABM part thermooxidative resistance, as compared t o competitive polyimides, i s very advantageously compensated f o r by the: - a b i l i t y to mold PABM compounds i n conventional thermoset transformation equipment (compression and t r a n s f e r molding, extrusion, free-sintering) to v o i d free, multi-pound parts i n rapid cure cycles; - very high c o m p a t i b i l i t y of a l l p a r t i c u l a t e and fibrous reinforcements with PABM r e s i n allowing the easy preparation and f a b r i c a t i o n of a wide d i v e r s i t y of molding compounds; - e x c e l l e n t long-term economics— comparable to epoxy molding compounds—whic large-volume a p p l i c a t i o n 2.

PABM Resin 2.1 Chemistry.

KINEL/KERIMID 601 chemistry was t a l k on polyamino-

bismaleimides · The t o t a l absence of v o l a t i l e generation during cure serves to explain the reproducible and f a c i l e preparation of void-free composites and the t o t a l i n s e n s i t i v i t y of molded parts to thermal shock. 2.2 Processing. PABM u n f i l l e d r e s i n and molding compounds are generally processed a t 380-480°F and 3000 p s i i n 2-30 minute c y c l e s . Cycle times depend upon the s p e c i f i c reinforcement used and the s i z e of the f i n a l part. T y p i c a l graphite powder r e i n f o r c e d PABM bearings are molded i n 2-5 minutes. Transfer molding times run 1-5 minutes. PABM f r e e - s i n t e r i n g i s achieved at 15,000 p s i i n a 15 sec. cold-mold c y c l e time. Large (2 to 5 pounds) f i b e r - g l a s s r e i n f o r c e d PABM parts are cured more r a p i d l y than comparable epoxy moldings owing to the absence of exotherm (5-10 minute cycles). Post-cures, f o r maximum development of part mechanicals and heat resistance, are conducted a t 450480°F f o r 2-16 hours. Step post-cures are unnecessary. 2.3 Properties. PABM parts are capable of operating continuously a t 500°F f o r 1-2000 hours. PABM pieces possess the room and elevated temperature mechanicals and e l e c t r i c a l s , the f i r e , cryogenic

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CO

1 Où ft*

Ϊ «

ε

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temperature, s o l v e n t , m o i s t u r e , and steam r e s i s t a n c e t r a d i t i o n a l l y expected o f polyimides. Heat d i s t o r t i o n temperatures r u n 660°P and o v e r for g l a s s - f i b e r r e i n f o r c e d compositions. P o l y i m i d e p a r t p r o p e r t i e s a r e custom t a i l o r e d by judicious selection of f i l l e r s . T y p i c a l f i l l e r s and e n g i n e e r i n g end-uses o f r e s u l t a n t p a r t s i n c l u d e : - chopped g l a s s f i b e r s f o r j e t engine p a r t s and e l e c t r i c a l connectors? - g r a p h i t e powder, molybdenum d i s u l f i d e , o r PTFE f o r b u s h i n g s , bearings,, t h r u s t washers, v a l v e s e a t s , f a c e s e a l s and p i s t o n r i n g s ? - chopped g r a p h i t e f i b e r s f o rzero-coefficient of e x p a n s i o n r o t a r y a i r compressor vanes; - a s b e s t o s f i b e r s f o r brake l i n i n g s and vanes; - diamonds, Borazon o x i d e f o r a b r a s i v e wheels - mica o r s i l i c a powder f o r p o t t e d and e n c a p s u l a t e d e l e c t r o n i c components. S p e c i f i c p r o p e r t i e s o f t h e s e c o m p o s i t i o n s w i l l be d i s c u s s e d i n subsequent s e c t i o n s . 3.

S t r u c t u r a l KINELS

3.1 D e s c r i p t i o n . Two major f a m i l i e s o f PABM compounds have been d e v e l o p e d t o s a t i s f y t h e needs o f two d i s t i n c t t y p e s o f end-uses. The f i r s t s e r i e s o f PABMs i s d i r e c t e d t o a p p l i c a t i o n s where m e c h a n i c a l p r o p e r t i e s a r e o f prime import; t h e s e PABMs a r e f i b e r glass reinforced. KINEL 5504 i s 65% f i l l e d w i t h q u a r t e r - i n c h g l a s s f i b e r s , e x h i b i t s the highest mechanical p r o p e r t i e s o f any KINEL (49,500 p s i f l e x u r a l s t r e n g t h and 3.25 MSI f l e x u r a l modulus a t room t e m p e r a t u r e ) , and i s g e n e r a l l y compression molded. C u r r e n t commercial end-uses i n c l u d e j e t engine p a r t s ; t y p i c a l o f these a r e the b l o c k e r doors used f o r r e t r o - t h r u s t i n t h e R o l l s - R o y c e RB.211 e n g i n e s o f t h e Lockheed L-1011. KINEL 5514 i s 50% f i l l e d w i t h e i g h t h - i n c h g l a s s f i b e r s and i s s p e c i a l l y f o r m u l a t e d f o r t h i n w a l l moldings. T y p i c a l end-uses i n c l u d e h i g h - t e m p e r a t u r e e l e c t r i c a l c o n n e c t o r s and h i g h p r e c i s i o n m o l d i n g s . KINEL 5515 i s a m o d i f i e d v e r s i o n o f 5514, which i s p a r t i c u l a r l y s u i t e d f o r t r a n s f e r molding a p p l i c a tions. KINEL 5515 may be c u r e d i n 1-5 minutes a t 380°F. 3.2 I n i t i a l P r o p e r t i e s . R e p r e s e n t a t i v e mechanical, thermal, and p h y s i c a l p r o p e r t i e s o f t h r e e s t r u c t u r a l

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

32,500 18,400

D 695

D 256

Compressive Strength, p s i - a t 77°F ( 25°C) - a t 482°F (250°C)

Impact Strength, f t χ lb/in·

* Measurements were made on molded t e s t specimens.

Notched Izod a t 77 F Specimen width: 0.5 i n .

17

27,000 22,700

D 638

Tensile Strength, p s i - a t 77°F ( 25°C) - a t 482°F (250°C)

U

3,250,000 2,980,000 2,420,000

49,500 42,700 35,500 D 790

ASTM D 790

KINEL 5504

Flexural Modulus, p s i - a t 77°F ( 25°C) - a t 392°F (200°C) - a t 482°F (250°C)

6

F l e x u r a l Strength, p s i - a t 77°F ( 25 C) - a t 392°F (200OC) - a t 482°F (250°C)

MECHANICAL PROPERTIES*

KINEL 5504 AND 5514 PROPERTIES

TABLE 1

5.6

34,000 19,800

6,400 5,400

1,980,000 1,710,000 1,490,000

21,300 18,500 17,700

KINEL 5514

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

1.9 119

0.1

ASTM D 1299 ASTM D 785

Mold s h r i n k a g e , %

Hardness

g r a v i t y , g/cm lb/cu.ft.

3.48

b

0.2

1.7 106

2.46

13xl0~£ 8xl0~

660

KINEL 5514

nonflammable

15xl0~*> 8x10"^

660

KINEL 5504

ASTM D 792

Specific

PHYSICAL PROPERTIES

2

3

in/in/°C in/in/°F

Thermal c o n d u c t i v i t y Btu. in/ft .hr.°F

from 25 t o 300°C from 77 t o 5 7 2 ° F

ASTM D 696

o f l i n e a r expansion

ASTM D 648

Coefficient

Ρ AIR 0978/A

temperature,

Flammability

Heat D i s t o r t i o n

THERMAL PROPERTIES

KINEL 5504 AND 5514 PROPERTIES

TABLE I ( c o n t i n u e d )

130

NEW

INDUSTRIAL

POLYMERS

KINELs a r e shown i n T a b l e s I and I I . P a r t i c u l a r l y o u t s t a n d i n g , f o r a l l t h r e e KINELs, i s t h e v e r y low mold s h r i n k a g e — 0 . 1 % f o r 5504, 0.2% f o r 5514, and 0.1-0.3% f o r 5515. KINELs a d d i t i o n a l l y p o s s e s s good e l e c t r i c a l p r o p e r t i e s o v e r a wide range o f temperatures and f r e quencies. These a r e shown i n T a b l e I I I . 3.3 E l e v a t e d Temperature P r o p e r i t i e s . KINELs 5504, 5514, and 5515 r e t a i n a v e r y l a r g e p e r c e n t a g e o f t h e i r room temperature p h y s i c a l s a t e l e v a t e tempera^ture. The t h e r m o p h y s i c a l p r o f i l e s o f KINELs 5504 and 5514 a r e g r a p h i c a l l y shown i n F i g u r e s 2-4 f o r f l e x u r a l s t r e n g t h , f l e x u r a l modulus, and t e n s i l e s t r e n g t h . V a l u e s f o r comparable f i l l e d e p o x i e s and p h e n o l i c s a r e i n c l u d e d f o r comparison % retention o 480°F a r e shown below. KINEL 5504 KINEL 5514 Flexural Strength 72% 83% F l e x u r a l Modulus 74% 75% Tensile Strength 84% 85% Compressive S t r e n g t h 57% 58%

KINEL 5515 79% 67%

F i n a l l y t h e low f l e x u r a l c r e e p o f KINEL 5504 a t 392°F and under 2,500 p s i p r e s s u r e i s shown o v e r 100 hours i n F i g u r e 5. 3.4 Thermal A g i n g . In a d d i t i o n to t h e i r high h e a t d i s t o r t i o n temperatures and r e t e n t i o n o f p r o p e r t i e s a t e l e v a t e d t e m p e r a t u r e s , PABMs e x h i b i t o u t s t a n d ing thermooxidative s t a b i l i t i e s . F i g u r e s 6 t o 9 show the v a r i a t i o n s i n f l e x u r a l s t r e n g t h s and m o d u l i o f KINELs 5504 and 5514, a f t e r a g i n g i n a i r a t temperatures o f 392°F (200°C) and 482°F (250°C) f o r s e v e r a l thousand h o u r s . A l l agings were conducted on p r e - c u t t e s t specimens. T a k i n g as h a l f - l i f e c r i t e r i o n t h e r e t e n t i o n o f 50% o f i n i t i a l f l e x u r a l s t r e n g t h (measured a t room t e m p e r a t u r e ) , t h e f o l l o w i n g t h e r m a l r a t i n g s a r e obt a i n e d f o r KINEL 5504: A g i n g Temperature 482°F (250°C) 392°F (200°C) 365°F (185°C)

Half-life 1,300 h r s . 10,000 h r s . 20,000 h r s .

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

10.

DARMORY

131

Processable Polyimides

TABLE I I . KINEL 5515 PROPERTIES

MECHANICAL PROPERTIES ASTM D 790

F l e x u r a l Strength, p s i - a t 77°F - a t 390°F - a t 480°F

16,300 15,000

( 25°C) (200°C) (250°C) ASTM D 790

F l e x u r a l Modulus, p s i - a t 77°F - a t 390°F - a t 480°F

1,170,000 890,000 780,000

( 25°C) (200°C) (250°C)

Impact S t r e n g t h , f t χ l b / i n .

ASTM D 256 1.5 - 2.0

Notched Izod a t 77°F

PHYSICAL PROPERTIES Specific gravity,

Mold

g/cm

ASTM D 792

3

shrinkage

- perpendicular to transfer - p a r a l l e l to transfer Hardness

ASTM D 1299 axis

1.6

0.1 - 0.3% 0.2 - 0.3%

axis ASTM D 785 126

- Rockwell M Water a b s o r p t i o n - Change i n w e i g h t a f t e r 24 h immersion i n water a t 77°F, %

+0.6

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

F a c t o r a t 1MHz ASTM D 150

Volume R e s i s t i v i t y a t 1MHz (ohm.cm) ASTM D 257 - a t 77°F - a t 212°F - a f t e r 24 h r water immersion

- a t 77°F - a t 390°F a f t e r 24 h r water immersion

Dissipation

D i e l e c t r i c C o n s t a n t a t 1MHz ASTM D 150 - a t 77°F - a t 390°F - a f t e r 24 h r water immersion

D i e l e c t r i c S t r e n g t h a t 1MHz (V/mil) - ASTM D 149 - a t 77°F - a t 390°F - a f t e r 24 h r water immersion

14 2 X 10

14 1.5x10

1 χ 1016

0.017 0.017 0.016

15 5 X 10

0.007 0.006 0.009

4.5 4.6

425

375

4.7 4.8

450

KINEL 5514

500

KINEL 5504

KINEL ELECTRICAL PROPERTIES

TABLE I I I

1.5 χ 10 15 9 X 1014 14 7.3 χ 10

0.012

0.003

5.2

5.2

525 450 475

KINEL 5515

s 5

>

DARMORY

Processable Polyimides

Figure 2.

Flexural strength vs. temperature

Figure 3.

Flexural modulus vs. temperature

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

NEW

134

Figure 4.

INDUSTRIAL

Tensile strength vs. temperature

Figure 5. Flexural creep of Kinel 5504 vs. time at 392°F (200°C) and under a 2500 psi (175 bars) stress

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

POLYMERS

DARMORY

Processable Polyimides

Figure 6. Flexural strength vs. aging time at 392°F and 482°F (250°C), tested at 77°F (25°C)

(200°C)

Figure 7. Flexural strength vs. aging time at 392°F (2O0°C) and 482°F (250°C), tested at 392°F (200°C)

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

NEW

INDUSTRIAL

Figure 8. Flexural modulus vs. aging time at 392°F (200°C) and 482°F (250°C), tested at 77°F (25°C)

Figure 9. Flexural modulus vs. aging time at 392°F (200°C) and 482°F (250°C), tested at 392°F (200°C)

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

POLYMERS

10.

Processable Polyimides

DARMORY

137

3.5 C o e f f i c i e n t of Linear Thermal Expansion. The c o e f f i c i e n t s of l i n e a r expansion of KINELs 5504 and 5514 are quite low: 8 χ 10~fin/in/°F(15 χ 10"fcm/cm/°C) f o r KINEL 5504 7 χ 10" in/in/°F(13 χ 10" cm/cm/°C) f o r KINEL 5514. 6

6

They are of the same order of magnitude as those of many metals and a l l o y s . The dimensional s t a b i l i t y of parts molded from PABMs i s exceptional. 3.6 F i r e Resistance. PABMs e x h i b i t outstanding f i r e r e s i s t a n c e . They are the only ones to meet AIR 0978/A S p e c i f i c a t i o n (French A i r c r a f t Standard) This exceptional f i r e resistanc in fireproof a i r c r a f S p e c i f i c LOI values are: KINEL 5504—43.3? KINEL 551436.4. 3.7 Radiation Resistance. Parts molded i n PABMs are unaffected by exposure to 1 0 rads. PABMs are therefore i d e a l l y suited f o r a p p l i c a t i o n s , such as e l e c t r i c a l supports and i n s u l a t o r s , i n the hot zones of nuclear accelerators and reactors. 1 0

4.

S e l f - L u b r i c a t i n g KINELS

4.1 Description. The second major family of PABM compounds i s d i r e c t e d t o a p p l i c a t i o n s where low wear rates, low c o e f f i c i e n t s of f r i c t i o n , and good dimen­ s i o n a l s t a b i l i t y under load are sought. For these enduses, graphite, molybdenum d i s u l f i d e , and PTFE f i l l e d PABMs have been developed. KINELs 5505 and 5508 are graphite f i l l e d compounds (25% and 40%, r e s p e c t i v e l y ) . The f i r s t affords higher mechanicals, the second better wear and l u b r i c i t y p r o p e r t i e s . T y p i c a l a p p l i c a t i o n s f o r KINELs 5505 and 5508 include: face seals and thrust washers; s l i p - o n p i s t o n rings f o r a i r compressors; low speed, high load journal bearings (speeds l e s s than 100 fpm); replace­ ment f o r carbon/graphite mechanical goods. KINEL 5511 i s an asbestos f i b e r / g r a p h i t e powder f i l l e d compound. Asbestos f i b e r s impart r e s i l i e n c e to the formulation. End-uses include: valve seats; seals; snap-on piston rings and vanes f o r rotary pumps. KINEL 5517 i s graphite and molybdenum d i s u l f i d e f i l l e d . Wear, f r i c t i o n a l properties, and a p p l i c a t i o n s are s i m i l a r t o those of 5505. 5517 i s the most cost-

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

Impact s t r e n g t h a t 77°F (25°C)-Notched Izod ft χ lb/in.

Compressive s t r e n g t h , p s i 77°F ( 25°C) 392°F (200°C)

0.25

22,200 14,600

^1

5,700 5,000 4,200

Tensile strength, p s i 77°F ( 25°C) 392°F (200°C) 482°F (250°C)

a t break, %

750,000 680,000 640,000

F l e x u r a l modulus, p s i 77°F ( 25°C) 392°F (200°C) 482°F (250°C)

Elongation

12,800 10,000 7,800

MECHANICAL PROPERTIES Flexural strength, p s i 77°F ( 25°C) 3920F (200°C) 482°F (250°C)

KINEL 5505

0.4

15,700 11,100

-CI

4,700 3,800 3,100

1,050,000 1,010,000 1,000,000

11,400 8,500 7,800

KINEL 5508

0.25

20,000 15,200

550

KINEL 5511

TABLE IV (continued) SELF-LUBRICATING KINEL PROPERTIES

140

NEW

INDUSTRIAL

POLYMERS

e f f e c t i v e o f a l l g r a p h i t e KINELs s i n c e i t may be f r e e sintered. Typical processing conditions are: cold p r e s s 15-30 s e c . a t 15,000 p s i and f r e e - s i n t e r from 360-480°F i n a programmed oven. A u t o m a t i c c o l d p r e s s i n g o f p a r t s c a n a l s o be used. KINEL 5518 i s PTFE f i l l e d and e x h i b i t s t h e b e s t s e l f - l u b r i c a t i o n p r o p e r t i e s o f a l l KINELs. C o e f f i c i e n t s o f f r i c t i o n and wear r a t e s a r e comparable t o the b e s t o b t a i n e d w i t h any f i l l e d PTFE compound. A d d i t i o n a l l y , PTFE compounds a r e f o r m u l a t e d t o a f f o r d e x c e l l e n t v a l u e s f o r one o r t h e o t h e r o f t h e s e p r o p e r t i e s ? KINEL 5518 a f f o r d s o u t s t a n d i n g v a l u e s f o r both. High-speed, h i g h - l o a d b e a r i n g s a r e t h e p r i n c i p a l o u t l e t f o r KINEL 5518? such b e a r i n g s : o p e r a t e a t s u r f a c e v e l o c i t i e s up t o 1000 fpm and PV's o f 10-20,000, a r e n o t temperature r e s t r i c t e do n o t c o l d f l o w . Finally s t a n d i n g e l e c t r i c a l p r o p e r t i e s (see T a b l e I V ) . 4.2 I n i t i a l P r o p e r t i e s . R e p r e s e n t a t i v e mechanic a l , t h e r m a l , and p h y s i c a l p r o p e r t i e s o f s e l f - l u b r i c a t i n g PABMs a r e shown i n T a b l e TV. P a r t i c u l a r l y noteworthy a r e t h e h i g h m e c h a n i c a l p r o p e r t i e s , u n a t t a i n a b l e w i t h t y p i c a l t h e r m o p l a s t i c b e a r i n g compounds. T e n s i l e s t r e n g t h s r u n 10,000 p s i and up, compressive s t r e n g t h s a r e t y p i c a l l y i n e x c e s s o f 15,000 p s i . 4.3 F r i c t i o n and Wear. G r a p h i t e , molybdenum d i s u l f i d e , and PTFE f i l l e d PABMs e x h i b i t p a r t i c u l a r l y low wear r a t e s i n d r y f r i c t i o n v s m e t a l a t h i g h PV's and, i n p a r t i c u l a r , a t h i g h p r e s s u r e s a p p l i e d a t low velocities. F i g u r e 10 shows t h e v a r i a t i o n s o f KINEL 5505 and 5508 c o e f f i c i e n t s o f f r i c t i o n v s p r e s s u r e a t a g i v e n velocity. C o n v e r s e l y t o what i s o b s e r v e d w i t h o t h e r competi t i v e s e l f - l u b r i c a t i n g m a t e r i a l s , KINELs 5505 and 5508 f r i c t i o n a l p r o p e r t i e s a r e r e t a i n e d and even improved a t e l e v a t e d temperatures as shown i n F i g u r e 11. A d d i t i o n a l c o e f f i c i e n t o f f r i c t i o n and wear r a t e d a t a f o r s e l f - l u b r i c a t i n g PABMs a r e shown i n T a b l e s VI and V I I , r e s p e c t i v e l y . Both s e t s were o b t a i n e d on H" d i a m e t e r j o u r n a l b e a r i n g s o p e r a t i n g on hardened s t e e l shafts. Note t h a t dynamic d r y c o e f f i c i e n t s o f f r i c t i o n a r e l e s s than 0.1· 4.4 P r o p e r t i e s a t E l e v a t e d Temperatures. I n a d d i t i o n t o t h e i r v e r y low wear r a t e s , s e l f - l u b r i c a t i n g PABMs r e t a i n t h e i r e l e v a t e d temperature p r o p e r t i e s t o an e x c e p t i o n a l e x t e n t .

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

DARMORY

Processable Polyimides

Figure 10.

Figure 11.

Kinel 5505 and 5508 coefficient of friction vs. pressure

Kinel 5505 and 5508 coefficient of friction vs. temperature

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

142

NEW

INDUSTRIAL

POLYMERS

F i g u r e s 12 and 13 show t h e p e r c e n t r e t e n t i o n o f f l e x u r a l s t r e n g t h s and m o d u l i f o r KINELs 5505, 5508, and 5517 (compression molded and f r e e - s i n t e r e d ) . 4.5 E f f e c t o f Water on KINELs. Water and moist u r e are c o n d i t i o n s f r e q u e n t l y encountered i n s e l f lubricating applications. P a r t w e i g h t change a f t e r t w e n t y - f o u r hour immersion i s m i s l e a d i n g f o r two r e a s o n s — w e i g h t change i s an i n a c c u r a t e r e f l e c t i o n o f d i m e n s i o n a l and m e c h a n i c a l changes and few p a r t s a r e designed t o operate f o r only twenty-four hours. To o b t a i n a more v a l i d assessment o f PABM water r e s i s t a n c e , molded r i n g s were immersed i n 175°F (80°C) water u n t i l no f u r t h e r d i m e n s i o n a l o r w e i g h t change was n o t e d . P a r t s t a b i l i z a t i o n was o b s e r v e d i n a l l c a s e s between 1000 an mensions were: O.D.-1.2" D i m e n s i o n a l changes o f I.D. and O.D. and w e i g h t i n c r e a s e s a r e g i v e n below f o r a l l s e l f - l u b r i c a t i n g KINELs.

KINEL 5505 5508 5511 5517 5518

% O.D. INCREASE 0.45 0.45 0.35 0.60 0.85

% I.D. INCREASE 0.55 0.45 0.35 0.65 0.95

% WEIGHT GAIN 3.5 2.95 3.1 3.55 3.65

E x c e p t f o r KINEL 5518, where t h e PTFE f i l l e r p l a y s a d e t e r m i n i n g r o l e , no d i m e n s i o n a l change i s g r e a t e r t h a n 0.65%. F u r t h e r , water a b s o r p t i o n i s on KINEL s u r f a c e o n l y , r a t h e r t h a n i n t o c o r e o f p a r t . PABMs a r e thus i d e a l l y s u i t e d f o r o p e r a t i o n i n h o t water and h i g h - h u m i d i t y environments and i n s i t u a t i o n s where r a p i d t h e r m a l c y c l i n g , from m o i s t u r e s a t u r a t e d atmospheres, o c c u r s . 5.

Summary

KINEL m o l d i n g powders and KERIMID 601 l a m i n a t i n g r e s i n s a r e based on a t h e r m o s e t t i n g p o l y i m i d e , which cures without e v o l u t i o n of v o l a t i l e s . KINEL compounds a r e t r a n s f o r m e d by compression, t r a n s f e r , o r e x t r u s i o n m o l d i n g i n t o v o i d - f r e e p a r t s , whose thermomechanical p r o p e r t i e s exceed t h o s e a t t a i n a b l e from c o n v e n t i o n a l t h e r m o p l a s t i c s or thermosets.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

10.

DARMORY

Figure 12.

Figure 13.

Processable Polyimides

143

Kinel 5505, 5508, and 5517 flexural strength vs. temperature (% retention)

Kinel 5505, 5508, and 5517 flexural modulus vs. temperature (% retention)

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KINEL s t r u c t u r a l and s e l f - l u b r i c a t i n g compounds KERIMID 601 l a m i n a t e s e x h i b i t : h i g h t e n s i l e f l e x u r a l , and impact s t r e n g t h s ; low wear r a t e s and c o e f f i c i e n t s o f f r i c t i o n ; e x c e l l e n t r e t e n t i o n of mechanical p r o p e r t i e s a t 480°P (250°C); - s e v e r a l thousand hours o f t h e r m a l s t a b i l i t y a t 390-480°F (200-250°C); - easy m o l d a b i l i t y and m a c h i n a b i l i t y ; - outstanding dimensional s t a b i l i t y ; - e x c e p t i o n a l c r e e p r e s i s t a n c e ; and - i n s e n s i t i v i t y to f i r e , chemical reagents, solvents, o i l s , c r y o g e n i c temperatures, r a d i a t i o n s , and moisture. These p r o p e r t i e s , combined w i t h e x c e l l e n t l o n g term economics, i n s u r p l i c a t i o n s w i l l be and -

6.

Acknowledgments

Data p r e s e n t e d i n t h i s paper were d e v e l o p e d by Rhone-Poulenc i n F r a n c e .

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

11 Catalytic Trimerization of Aromatic Nitriles for Synthesis of Polyimide Matrix Resins LI-CHEN HSU NASA, Lewis Research Center, Cleveland, Ohio 44135

Synopsis Aromatic nitriles may be t r i n t e r i z e d a t moderate tempera t u r e and p r e s s u r e w i t h p - t o l u e n e s u l f o n i e acid as catalyst. S t u d i e s were c o n d u c t e d t o establish t h e effect o f t h e r e action t e m p e r a t u r e , p r e s s u r e , t i m e , and catalyst concentration on yield o f t h e trimerized product. Trimerization s t u d i e s were a l s o c o n d u c t e d t o establish t h e effect o f substituting e l e c t r o n d o n a t i n g o r w i t h d r a w i n g groups on benzonitrile. Preliminary results o f u s i n g the catalytic trimerization approach to prepare s-triazine cross-linked p o l y i m i d e / g r a p h i t e fiber c o m p o s i t e s a r e p r e s e n t e d . Introduction H i g h t e m p e r a t u r e r e s i n / f i b e r c o m p o s i t e s have t h e p o t e n t i a l o f m e e t i n g t h e p e r f o r m a n c e r e q u i r e m e n t s f o r many advanced a e r o s p a c e s t r u c t u r e s . The c o m p o s i t e s need t o e x h i b i t r e t e n t i o n o f mechanical p r o p e r t i e s during continuous use a t 316°C (600°F) o r above ( 1 ) . Among t h e h i g h t e m p e r a t u r e r e s i n s , p o l y a m i d e s occupy a p r e e m i n e n t p o s i t i o n . Aromatic polyimides f P I s ) e x h i b i t thermal s t a b i l i t y i n e x c e s s o f 500°C (932 F) as d e t e r m i n e d by t h e r m a l g r a v i = m e t r i c a n a l y s i s ( 2 ) . However, p r o c e s s i n g d i f f i c u l t i e s have l i m i t e d t h e i r use as m a t r i c e s i n r e s i n / f i b e r composites. V a r i o u s a p p r o a c h e s have been u s e d t o s o l v e t h e p r o c e s s a b i l i t y p r o b l e m o f p o l y i m i d e s . L u b o w i t z (3) and B u r n s e t . a l . (4) d e v e l o p e d a new s y s t e m o f p r o c e s s a b l e a d d i t i o n - t y p e (A-type) P I s by e n d - c a p p i n g i m i d e o l i g o mers w i t h n o r b o r n e n y l g r o u p s . A f t e r removal o f the s o l v e n t , the norbornene-terminated imide oligomers are p o l y m e r i z e d t h r o u g h t h e d o u b l e bonds w i t h o u t e v o l u t i o n o f b y p r o d u c t s . S e r a f i n i e t . a l (5) and D e l v i g s e t . a l . (j3) d e v e l o p e d an improved p r o c e s s i n g t e c h n i q u e f o r A - t y p e P I s c a l l e d t h e i n s i t u p o l y m e r i z a t i o n o f monomeric r e a c t a n t s (PMR). T

T

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Although the i n s i t u PMR approach does provide v o i d f r e e A-tyge PI composites with good property retention at 316 C (600 F ) , the a l i c y c l i c r i n g structure derived from the norbornene groups does appear to l i m i t the thermo-oxidative s t a b i l i t y (TOS) of A-type P I s Γ7). To achieve A-type PI?s with improved TOS at 316°C (600 F) or above, our approach was to replace the norbornenyl groups with aromatic n i t r i l e s . T r i m e r i z a t i o n of aromatic n i t r i l e - t e r m i n a t e d imide oligomers should lead to new polyimides containing t r i a r y l - s - t r i a z i n e r i n g s . T r i a r y l - s - t r i a z i n e r i n g i s known to e x h i b i t good thermal s t a b i l i t y (8). The purpose o f the present i n v e s t i g a t i o n was to study the t r i m e r i z a t i o n o f aromatic n i t r i l e s under the conven­ t i o n a l r e s i n / f i b e r composite f a b r i c a t i o n conditions using p-toluenesulfonic a c i d as a c a t a l y s t . T r i m e r i z a t i o n para­ meters i n v e s t i g a t e d include time, and concentratio nature o f aromatic n i t r i l e s on t r i m e r i z a t i o n was also studied. Also presented are preliminary r e s u l t s on the use of the c a t a l y t i c t r i m e r i z a t i o n o f the n i t r i l e - t e r m i n a t e d imide oligomers to f a b r i c a t e graphite f i b e r r e i n f o r c e d composites. Q

T

Experimental Procedure M a t e r i a l s . A l l of the aromatic n i t r i l e s except pcyanophthalanil used i n t h i s study were purchased from commercial sources and used as received. The p-eyanophthal a n i l was synthesized by a method s i m i l a r to that used f o r synthesizing N-phthalyl-L-^-phenylalanine (9) except that p-aminobenzonitrile was used instead of L-phenylalanine. C a t a l y t i c T r i m e r i z a t i o n . About 0.01 mole of the aromatic n i t r i l e togethter with 0.5 to 5.0 mole percent of the p - t o l u e n e s u l f o n i c a c i d (PTSA) c a t a l y s t was introduced into a M-S-milliliter s t a i n l e s s s t e e l pressure v e s s e l . The v e s s e l was flushed with nitrogen gas and the i n i t i a l £ pressure i n the v e s s e l was v a r i e d from 0 to 2.76 MN/m (0 to M-00 psi) . The v e s s e l was then heated to temperatures i n the range of 100 to 316°C. The selected temperature was maintained f o r 24 to 90 hours. The PTSA c a t a l y s t and unreacted n i t r i l e were then removed from the product by washing with water followed by d i s t i l l a t i o n under reduced pressure. The product was then r e c r y s t a l l i z e d from xylene or g l a c i a l a c e t i c a c i d . M e l t i n g p o i n t and i n f r a r e d spectrum were determined f o r i d e n t i f i c a t i o n purposes. Results and Discussion T r i m e r i z a t i o n Study.

Bengelsdorf (10) reported that

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

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aromatic n i t r i l e s could be t r i m e r i z e d i n the absence o f c a t a l y s t s at temperatures i n the range o f 350° to 500°C and at pressures which ranged from 3.55 χ 10 to 5.06 χ 10 MN/m (35,000 to 50,000 atmospheres). Cairns e t . a l . (11) used various alcohols as c a t a l y s t s and were able to e f f e c t t r i m e r i z a t i o n o f aromatic n i t r i l e s at 60° to 150°C and 0.3 χ 10 MN/m (above 3000 atmospheres). Kunz e t . a l . (12) employed c h l o r o s u l f o n i c a c i d to t r i m e r i z e aromatic n i t r i l e s at temperatures i n the range o f -10° to 30°C and at atmos­ pheric pressure. These l a t t e r workers used an excess o f c h l o r o s u l f o n i c a c i d which apparently served as both the s o l ­ vent and c a t a l y s t . Because o f the high pressures or the nature and quantity o f c a t a l y s t employed none o f the methods described above are s u i t a b l e f o r the synthesis o f high temperature r e s i s t a n t s - t r i a z i n e c r o s s - l i n k e d polyimide matrix r e s i n s f o r f i b e The aromatic n i t r i l study were b e n z o n i t r i l e and PTSA, r e s p e c t i v e l y . Studies were conducted to e s t a b l i s h the e f f e c t o f r e a c t i o n condi­ tions on y i e l d o f t r i m e r i z e d product. Figure 1 shows the e f f e c t o f varying the r e a c t i o n temperature on y i e l d between 100 and 290 C at a constant PTSA c a t a l y s t concentration o | 5 mole percent, pressure i n the range o f M-.14- to 5.17 MN/m (600 to 700 p s i ) , and f o r a constant r e a c t i o n time o f 66 hours. I t can be seen from the f i g u r e that there was no yieJLd at 100 C and the y i e l d nearly doubled on going from 232 to 290 C. Because o f p r a c t i c a l processing considera­ tions f o r the f a b r i c a t i o n o f f i b e r r e i n f o r c e d composites, higher temperatures were not i n v e s t i g a t e d . The e f f | c t o f reaction pressures i n the range o f 0.2 to 5.17 MN/m (30 to 750 psi) on y i e l d are shown i n f i g u r e 2. The data shown i n t h i s f i g u r e were obtained f o r reactions conducted with a PTSA concentration o f 5 mole percent at 232°C f o r 66 hours. The f i g u r e shows that the use o f higher pressures r e s u l t e d i n higher y i e l d s . Hereto, p r a c t i c a l processing considera­ t i o n l i m i t e d the highest pressure studied to 5.17 MN/m (750 p s i ) . Figure 3 shows the e f f e c t o f r e a c t i o n time on y i e l d f o r reactions conducted with 5 mole percent PTSA at 232°C (M-50°F) and 5.17 MN/m (750 p s i ) . I t can be seen i n the f i g u r e that the y i e l d upon i n c r e a s i n g r e a c t i o n time from 2M- to 66 hours underwent s l i g h t l y more than a two f o l d increase. Figure 4 which shows e f f e c t o f c a t a l y s t concen-p t r a t i o n on y i e l d shows that at 232°C (450°F) and 5.17 MN/m (750 p s i ) and 66 hours the y i e l d increased from 5% to 17% f o r a ten f o l d increase i n c a t a l y s t concentration. The r e s u l t s o f these t r i m e r i z a t i o n parameter studies i n d i c a t e d that u s e f u l l e v e l s o f t r i m e r i z e d product (cross­ l i n k s ) could be a n t i c i p a t e d from the use o f t h i s c a t a l y t i c t r i m e r i z a t i o n approach i n f a b r i c a t i n g r e s i n / f i b e r composites. Two a d d i t i o n a l points need to be made with respect to the

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

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Figure 1. Effect of reaction ternperature on trimerization of benzonitrile (PTSA 5 moles %, 600750 psi, 66hr)

Figure 3. Effect of reaction tiie on trimerization of benzonitrile (PTSA 5 mole %, 450°F, 750 psi)

INDUSTRIAL

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Figure 2. Effect of reaction pressure on trimerization of benzonitrih (PTSA 5 mole % 450°F 66 hr)

' $ f °* ^f trimerization of benzonitrih (PTSA, 750 psi, 66 hr) 4

E

e

catal

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

™°v 450°F,

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y i e l d o f t r i m e r i z e d product. F i r s t , the y i e l d of t r i m e r i z e d product (cross-links) i n an a c t u a l r e s i n / f i b e r composite might be increased by p o s t - c u r i n g at elevated temperatures. And secondly, extensive c r o s s - l i n k i n g may not be necessary f o r improved composite p r o p e r t i e s and indeed may be delet e r i o u s to c e r t a i n composite mechanical p r o p e r t i e s . Nature o f Aromatic N i t r i l e s . The experimental r e s u l t s on the influence of r i n g substituents on the ease of trimeri z i n g b e n z o n i t r i l e s are summarized i n Table I . I t can be seen that the b e n z o n i t r i l e s bearing electron withdrawing r i n g substituents such as carboxyl and n i t r o groups are more susceptible to t r i m e r i z a t i o n than those bearing electron donating substituents such as methyl and methoxy groups. The lower y i e l d o f t r i m e r i z e d product from the o-nitrobenzon i t r i l e compared to p - n i t r o b e n z o n i t r i l by s t e r i c e f f e c t s . Th duct from the p-cyanobenzoic a c i d might have r e s u l t e d from a r e a c t i o n i n which the p-cyanobenzoic a c i d i t s e l f served as a c o - c a t a l y s t . For the synthesis o f processable polyimides, our res u l t s suggested the use of 4-cyanophthalic anhydride as the end-capping reagent. The 4-eyanophthalic anhydride or i t s esters might be p r e f e r r a b l e because the electron withdrawing carbonyl groups would be d i r e c t l y attached to the aromatic r i n g containing the n i t r i l e to be t r i m e r i z e d . However, because of the commercial a v a i l a b i l i t y of p-aminob e n z o n i t r i l e , i t was s e l e c t e d as the end-capping reagent f o r preliminary s t u d i e s . T r i m e r i z a t i o n o f p-Cyanophthalanil. p-Cyanophthaianil was synthesized as the model compound to study the e f f e c t i v e ness of PTSA i n promoting t r i m e r i z a t i o n o f a chemical structure which would be found i n the polyimide precursors. p-Cyanophthalanil was prepared from commercially a v a i l a b l e p-aminobenzonitrile and p h t h a l i c anhydridg. The whije c r y s t a l l i n e powder has a melting p o i n t o f 189 C ( l i t . 187 C, r e f . 16). I t s i n f r a r e d spectrum showed a n i t r i l e band at 2240 cm" , imide bands at 1795, 1755, 1735, and 1380 c n r , and phenyl r i n g bands at 1610 and 1520 cm" respectively ( f i g . 5(a)). C a t a l y t i c t r i m e r i z a t i o n o f p-cyanophthalanil with 5 mole percent p - t o l u e n e s u l f o n i c a c i d at 250-300 C and 4.97 to 5.52 MN/m (720-800 p s i ) f o r 90 hours gave a 97% y i e l d product, with a m.p. > 3 4 0 ° C . The i n f r a r e d spectrum showed the disappearance of the n i t r i l e band at 2240 cm" and the broadening of the s - t r i a z i n e bands at 1520 and 1380 cm" ( f i g . 5 ( b ) ) . Further i d e n t i f i c a t i o n o f the formation o f the s - t r i a z i n e was done by r e f l u x i n g the t r i m e r i z e d product with a 10% NaOH s o l u t i o n f o r 4 hours. The i n f r a r e d spectrum of 1

1

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In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

M. P. C

5.0 6.0 14.0 37.8 52.3 75.0

Percent yield

14

15

13

13

13

> 340 (278-9 ) .13, > 340 (217 and 224") 232-235 (232 ) > 340 > 340 (> 360 ) > 340 (374-5 )

M. P. °C (Value in Lit. )

Trimerized Product

* Reaction conducted at 232 C, and 600 to 750 psi., with 5 mole percent of PTSA catalyst for 48 hours.

p-Tolunitrile 26-28 Anisonitrile 55-56 Benzonitrile -14 o-Nitrobenzonitrile 102-106 p-Nitrobenzonitrile 146-149 p-Cyanobenzoic acid 220-222

Aromatic Nitrile

SUBSTITUTED BENZONITRILES

TABLE I. - CATALYTIC TRIMERIZATION* OF

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the insoluable h y d r o l y s i s product showed that those imide bands at 1795, 1755, 1735, and 1380 cm" had nearly d i s appeared (or greatly weakened). The c h a r a c t e r i s t i c s - t r i azine band at 1520 cm" was not affected ( f i g . 5 ( c ) ) . 1

1

Trimerization of T e r e p h t h a l o n i t r i l e . Since terephthalon i t r i l e has two n i t r i l e groups and the n i t r i l e group i t s e l f i s also electron withdrawing, c a t a l y t i c t r i m e r i z a t i o n of t e r e p h t h a l o n i t r i l e should proceed r e a d i l y and r e s u l t i n a polymeric product expected to e x h i b i t good thermal s t a b i l i t y . The experimental r e s u l t s confirmed t h i s p r e d i c t i o n : Catal y t i c t r i m e r i z a t i o n of t e r e p h t h a l o n i t r i l e with 5 mole percent of PTSA c a t a l y s t at 232°C and 5.17 MN/m (750 psi) f o r 48 hours gave a product (99.5% y i e l d ) with a melting point >340°C (644 F ) . The i n f r a r e d spectrum of terephthalo n i t r i l e showed a very sharp aromatic r i n g ban i n f r a r e d spectrum of the trimerized product showed strong and broad c h a r a c t e r i s t i c s - t r i a z i n e r i n g bands at 1525 and 1370 cm" with a r e s i d u a l n i t r i l e band of medium strength at 2230 cm" ( f i g . 6(b)). Thermal gravimetric analysis ( f i g . 7) showed that the weight losses of t e r e p h t h a l o n i t r i l e polymer were about 7% a f t e r heating to 316 C (600 F) and 18% a f t e r heating to 538°C (1000°F) r e s p e c t i v e l y . Anderson and Holovka (17) reported weight losses of about 25% a f t e r heatigg to 316°C (600°F) and 75% a f t e r heating to 538°C (1000 F) r e s p e c t i v e l y from the t e r e p h t h a l o n i t r i l e polymer which they obtained by t r e a t i n g t e r e p h t h a l o n t r i l e with c h l o r o s u l f o n i c a c i d at 0°C. T h i s greater thermal oxidative s t a b i l i t y of the trimerized product using PTSA as the catal y s t may be due to having achieved a higher cross-linkp density during reaction at 232°C (450 F) and 5.17 MN/m (750 psi) . 1

Polyimide/Graphite F i b e r Reinforced Composite. Since aromatic n i t r i l e - t e r m i n a t e d imide oligomers are s i m i l a r i n nature as p-cyanophthalanil and possess the same functiona l i t y as t e r e p h t h a l o n i t r i l e , they should be able to t r i m e r i z e and form the s - t r i a z i n e r i n g containing polymers under the s i m i l a r reaction conditions. Preliminary work f o r the synthesis of n i t r i l e terminated polyimides was c a r r i e d out by using p-aminobenzonitrile, 4,4'-methylenedianiline, 3,3 ,4,4 -benzophenonetetracarb o x y l i c dianhydride and methanol with 2.5 mole percent of PTSA c a t a l y s t . The stoichiometry of the monomeric reactants was adjusted to y i e l d an i n s i t u prepolymer having an average formulated molecular weight of 1500. Composite f a b r i c a t i o n and t e s t i n g were performed e s s e n t i a l l y according to the method used i n reference 5,. The r e s u l t s from some p r e l i m i nary composite f a b r i c a t i o n and characterization studies T

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In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

2500

2000

1500

1000 2500 2000 1500

1000

c

N-C /

J

100 200 300 400 500 600 700 800 900 1000 TEMPERATURE» °C cs-6886i

M. P. 231° C

M.P. > 3 4 0 ° C

V

Ν Ν « i

2

C)

Figure 7. TGA thermograms (10°C/min N ) of terephthalonitrile (O) and its trimerized product

100 0

80

60

40

20

0

C=N

Figure 6. (a) IR spectrum of terephthalonitrile; (b) IR spectrum of trimerized product of therephthalonitrile.

2000

1500 1

Figure 5. (a) IR spectrum of p-cyanophthalanil (PCPLAL); (b) IR spectrum of trimerized product of PCPLAL; (c) IR spectrum of PCPLAL trimerized product after refluxing with 10% NaOH for 4 hr.

FREQUENCY, C M '

2000

1500

(b) IR SPECTRUM OF TRIMERIZED PROD­ UCT OF PCPLAL

Λ·1 FREQUENCY, CM"

1500

(a) IR SPECTRUM OF Ρ CYANOPHTHALANIL (PCPLAL).

2000

(b)

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

a

8 370 10 130

temper­ ature

Room

4620 4520

No post cure 7500 6800

Post cure (16 hr 600° F)

600° F

Interlaminar shear strength, psi

Resin/fiber ~40/60 by weight.

1 2

men

Speci­

155 000 130 200

temper­ ature

Room

a

148 200 145 700

No post cure

167 500 157 500

Post cure (16 hr 600° F)

600° F

Flexural strength, psi

CROSS-LINKED PI/HMS FIBER COMPOSITES

TABLE Π. - MECHANICAL PROPERTIES OF TRIARYL-S-TRIAZINE

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i n d i c a t e that the t r i m e r i z a t i o n technique by employing PTSA c a t a l y s t provides high performance composites. Table I I shows the interlaminar shear strength and f l e x u r a l strength o f the t r i a r y l - s - t r i a z i n e cross-linkgd PI/HMS graphite composites at room temperature and 316 C with and without post curing. The data c l e a r l y i n d i c a t e that the HMS graphite f i b e r r e i n f o r c e d composite prepared from a n i t r i l e terminated PI exhibited very good r e t e n t i o n o f f l e x u r a l strength during short time exposure i n a i r at 316 C. More important, the data also i n d i c a t e that both the interlaminar shear strength and f l e x u r a l strength o f the composites improved a f t e r a 16 hour post cure a t 316 C. Apparently t h i s r e s u l t e d from an increase i n t r i a r y l - s t r i a z i n e r i n g s during post cure a t 316 C. Q

Conclusions The r e s u l t s o f t h i s i n v e s t i g a t i o n lead to the f o l l o w i n g conclusions: 1. Aromatic n i t r i l e s can be t r i m e r i z e d i n the temperature range o f 200° to 316°C (392° to 600 F) and pressure range o f 1.38 to 5.52 MN/m (200 to 800 p s i ) with p-toluen e s u l f o n i c a c i d as c a t a l y s t . 2. B e n z o n i t r i l e s bearing e l e c t r o n withdrawing r i n g substituents were found more susceptible to t r i m e r i z a t i o n than those bearing e l e c t r o n donating r i n g substituents. 3. Polyimide matrix r e s i n s containing s - t r i a z i n e crossl i n k s can be e a s i l y prepared u s i n g the aromatic n i t r i l e endcapping approach and t r i m e r i z a t i o n with a p-toluenesulfonic acid catalyst.

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

11.

HSU

Trimerization of Aromatic Nitriles

155

Literature Cited 1.

2. 3.

4.

5.

6.

7.

8.

9. 10. 11.

12. 13. 14. 15.

16. 17.

S e r a f i n i , T. T., "Aerospace S t r u c t u r a l M a t e r i a l s " , National Aeronautics Space Administration S p e c i a l P u b l i c a t i o n No. 227 (1970), p. 207. Sroog, C. E., J . Polymer S c i . , C, (1967), (16), p.1191. Lubowitz, H. R.; Wilson, E. R.; Kendrick, W. P.; and Burns, Ε. Α., French Patent 1,572,798 (1969); Lubowitz, H. R., U.S. Patent 3,528,950 (1970); Chem. Abstr., (72), 56085k. Burns, E. A.; Jones, R. J . ; Vaughan, R. W.; and Kendrick, W. P., "Thermally Stable Laminating Resins"(1970), Report TRW-11926-6013-RO-00; NASA CR-72633. S e r a f i n i , T. T.; Delvigs, P.; and Lightsey, G. R., "Theimally Stabl meric Reactants"(1972) S c i . , (16), p. 905. Delvigs, P.; S e r a f i n i , T. T.; and Lightsey, G. R., "Addition-Type Polyimides from Solutions of Monomeric Reactants", NASA TN D-6877 (1972); M a t e r i a l s Review f o r '72: Proceedings of the National Symposium and Exhi­ b i t i o n , Science of Advanced M a t e r i a l s and Process Engineering S e r i e s , (17) p. III-B-7-1. Jones, R. J . ; Vaughn, R. W.; and Burns, Ε. Α., "Ther­ mally Stable Laminating Resins"(1972), TRW Report 16402-6012-RO-00, NASA CR-72984. Blake, E. S.; Hammann, W. C.; Edwards, J . W.; Reichard, T. E.; and Ort, M. R., (1961) J. Chem. Eng. Data (16), p. 87. Bose, Α. Κ., "Organic Synthesis", (1973), C o l l e c t . (Vol.5), Wiley, NY, p. 973. Bengelsdorf, I . S., (1958), J. Amer. Chem. Soc., (80) p. 1442. Cairns, T. L. S.; Larchar, A. W.; and McKusick, B. C., U.S. Patent 2,503,999(1950); Chem. Abstr., (44), 6445c. Kunz, M. A.; K o e f e r l e , K.; and Berthold, E., U.S.Patent 1,989,042(1935); Chem. Abstr. (29), 1834. Smolin, Ε. M.; and Rapoport, L., "s-Triazines and D e r i v a t i v e s " , (1967)Interscience, NY, p. 172. Mahan, J. E.; and Turk, S. D., U.S. Patent 2,598,811 (1952); Chem. Abstr. (46), 10212h. F i l h o , G. Martins; da Costa, J. Goncalves; de Azevedo, F. Soares; and de Morais, J. O. Falcao, Anais. Acad. B r a s i l , Cienc. (35), 185 (1963). Bogert, M. T.; and Wise, L. E., J. Amer. Chem. Soc., (34) 693(1912). Anderson, D. R.; and Holovka, J. M., J . Polymer Sci., A-1, (4), 1689 (1966).

In New Industrial Polymers; Deanin, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1974.

12 Poly(p-Oxybenzoyl Systems): Homopolymer for Coatings; Copolymers for Compression and Injection Molding R O G E R S. S T O R M and S T E V E G . C O T T I S E K K C E L Division, The Carborundum Company, Niagara Falls, New York 14302

Development work The Carborundum Compan The e a r l y work m a i n l y f o c u s e d on t h e homopolymer (EKONOL) T h i s polymer has e x c e l l e n t t h e r m a l stability and a l s o v e r y good friction and wear properties and has f o u n d u s e r e c e n t l y as an additive t o PTFE for molded shapes and c o a t i n g s . The homopolymer however is v e r y difficult to fabricate by itself and t h i s has l e d to the development o f copolymer systems which retain t h e e x c e l l e n t t h e r m a l stability o f t h e homop o l y m e r ; b u t have sufficient f l o w for c o m p r e s s i o n and injection m o l d i n g . 1,2,3.

P a r a - h y d r o x y b e n z o i c a c i d (PHBA) by itself does not have sufficient reactivity t o p e r m i t t h e growth o f a polymer to any u s e f u l m o l e c u l a r w e i g h t . T h i s has been overcome by u s i n g t h e p h e n y l e s t e r o f PHBA. W i t h a slow controlled h e a t i n g to t e m p e r a t u r e s o f 320-340°C, t h i s monomer has sufficient reactivity t o build t h e m o l e c u l a r weight t o a u s e f u l level. However, the r e a c t i o n will n o t go t o 100% c o m p l e t i o n in the melt s t a t e . C a r r y i n g out the p o l y m e r i z a t i o n in a h e a t t r a n s f e r medium, s u c h as a m i x t u r e o f partially hydrogenated t e r p h e n y l s , p r o d u c e s a polymer w i t h a m o l e c u l a r w e i g h t o f —10,000. The p - o x y b e n z o y l polymer when p r o p e r l y made has a m e l t - i n g p o i n t above its d e c o m p o s i t i o n t e m p e r a t u r e ( > 1 0 0 0 ° F ) . The h i g h l y crystalline n a t u r e o f the polymer persists up t o -625°F. A t t h a t t e m p e r a t u r e , the polymer undergoes a b r o a d endotherm w h i c h most likely c o r r e s p o n d s t o the l o s s o f o r d e r in one d i m e n s i o n . However, even above this transition, the f l o w is e x t r e m e l y limited and is insufficient t o make c o m p r e s s i o n m o l d i n g a useful t o o l f o r fabrication. Only v e r y thin s e c t i o n s c a n be molded (