New Industrial Polymers

10 Processable Polyimides F. P.

DARMORY

Downloaded by CORNELL UNIV on May 31, 2017 | http://pubs.acs.org Publication Date: June 1, 1974 | doi: 10.1021/bk-1974-0004.ch010

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

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


10.

DARMORY

Processable Polyimides

125

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—which w i l l serve to insure numerous large-volume a p p l i c a t i o n s f o r PABMs. 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


NEW

INDUSTRIAL


126

POLYMERS

CO

1 Où ft*

Ϊ «

ε



10.

DARMORY


127

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, s i l i c o n e c a r b i d e , o r aluminum o x i d e f o r a b r a s i v e wheels; and - 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



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


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. % r e t e n t i o n o f room temperature p r o p e r t i e s a t 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 .


10.

DARMORY

131


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 12,800

( 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



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


Figure 2.

Flexural strength vs. temperature

Figure 3.

Flexural modulus vs. temperature


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


POLYMERS


DARMORY


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)



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)


POLYMERS

10.


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 resistance makes t h e i r use possible i n f i r e p r o o f a i r c r a f t i n t e r i o r panels and ducts. 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-



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

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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 d as a r e PTFE b e a r i n g s , and do n o t c o l d f l o w . F i n a l l y , 5518 p a r t s e x h i b i t o u t 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 .



DARMORY


Figure 10.

Figure 11.

Kinel 5505 and 5508 coefficient of friction vs. pressure

Kinel 5505 and 5508 coefficient of friction vs. temperature


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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 and 1200 h o u r s . I n i t i a l ring d i mensions were: O.D.-1.2"; I.D.-0.6"; t h i c k n e s s - 0 . 8 " . 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.



10.

DARMORY

Figure 12.

Figure 13.


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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 e t h a t numerous l a r g e - v o l u m e app l i c a t i o n s w i l l be found f o r PABMs.


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 .


New Industrial Polymers

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