Elastomeric Polyether-Ester Block Copolymers - ACS Publications

7 Elastomeric Polyether-Ester Block Copolymers

Downloaded by UCSF LIB CKM RSCS MGMT on November 19, 2014 | http://pubs.acs.org Publication Date: June 1, 1979 | doi: 10.1021/ba-1979-0176.ch007

Properties as a Function of the Structure and Concentration of the Ester Group JAMES R. W O L F E , JR. Elastomer Chemicals Department, Experimental Station, Ε. I. du Pont de Nemours and Co., Wilmington, D E 19898

Physical properties are related to ester-segment structure and concentration mers prepared methylene

in thermoplastic

poly ether-ester elasto

by melt transesterification

of

poly(tetra-

ether) glycol with various diols and aromatic

diesters. Diols used were 1,4-benzenedimethanol, 1,4-cyclohexanedimethanol, ethylene

glycol

terephthalate,

and the linear, aliphatic α,ω-diols from to

1,10-decane-diol.

isophthahte,

naphthalenedicarboxylate, ate.

Ester-segment

Esters

used

were

4,4'-biphenyldicarboxylate, and

structure

2,6-

m-terphenyl-4,4'-dicarboxylwas found to affect many

copolymer properties including ease of synthesis, molecular weight obtained, crystallization

rate, elastic recovery,

and

tensile and tear strengths.

T n t e r e s t i n p o l y e t h e r - e s t e r b l o c k c o p o l y m e r s that are b o t h t h e r m o p l a s t i c ·*• a n d e l a s t o m e r i c continues

at a s u s t a i n e d p a c e ( 1 - 9 ) .

recent c o m m u n i c a t i o n s h a v e dealt w i t h the t e t r a m e t h y l e n e

M o s t of t h e terephthalate/

p o l y ( t e t r a m e t h y l e n e e t h e r ) t e r e p h t h a l a t e c o p o l y m e r s w h i c h are c o n t i n u i n g to find i n c r e a s e d use i n c o m m e r c i a l a p p l i c a t i o n s r e q u i r i n g t h e r m o p l a s t i c elastomers w i t h s u p e r i o r p r o p e r t i e s . P a r t I of this series e x p l o r e d t h e s t r u c t u r e - p r o p e r t y r e l a t i o n s h i p s of tetramethylene

terephthalate/polyether

terephthalate

copolymers

as a

f u n c t i o n of v a r i a t i o n s i n the c h e m i c a l structure, m o l e c u l a r w e i g h t , a n d c o n c e n t r a t i o n of t h e p o l y e t h e r u n i t s (10). tested, p o l y ( t e t r a m e t h y l e n e

O f the polyether

monomers

e t h e r ) g l y c o l of m o l e c u l a r w e i g h t a p p r o x i

m a t e l y 1000 w a s f o u n d to p r o v i d e c o p o l y m e r s h a v i n g t h e best o v e r a l l c o m b i n a t i o n of p h y s i c a l p r o p e r t i e s a n d ease of synthesis. 0-8412-0457-8/79/33-176-129$05.75/0 © 1979 American Chemical Society

In Multiphase Polymers; Cooper, S., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1979.

130

MULTIPHASE POLYMERS

T h e w o r k r e p o r t e d here is c o n c e r n e d w i t h the syntheses a n d p r o p e r ties of p o l y e t h e r - e s t e r b l o c k c o p o l y m e r s c o n t a i n i n g p o l y ( t e t r a m e t h y l e n e e t h e r ) u n i t s of m o l e c u l a r w e i g h t of a p p r o x i m a t e l y 1000 as the a m o r p h o u s p o l y e t h e r b l o c k s a n d a v a r i e t y of esters as the c r y s t a l l i z a b l e h a r d segments. T h e p u r p o s e of this s t u d y is t o c o r r e l a t e changes i n synthesis a n d p r o p e r ties of these t h e r m o p l a s t i c a n d e l a s t o m e r i c c o p o l y m e r s w i t h c h a n g e s i n the c o n c e n t r a t i o n a n d n a t u r e of the ester segments, p a r t i c u l a r l y t h e types


of d i o l a n d d i a c i d .

Experimental

Nomenclature. P o l y ( t e t r a m e t h y l e n e e t h e r ) g l y c o l h a v i n g a n u m b e r - a v e r a g e m o l e c u l a r w e i g h t of a p p r o x i m a t e l y 1000 is c o d e d as P T M E g l y c o l . T h e s t r a i g h t - c h a i n , « , ω - d i o l s are c o d e d as 2 G , 3 G , . . . , 1 0 G w h e r e the n u m e r a l s represent the n u m b e r of m e t h y l e n e g r o u p s b e t w e e n t e r m i n a l h y d r o x y l s . T h u s 2 G is e t h y l e n e g l y c o l ; 5 G is 1 , 5 - p e n t a n e d i o l ; a n d 1 0 G is 1,10-decanediol. 1 , 4 - C y c l o h e x a n e d i m e t h a n o l is c o d e d as C D . T e r e p h thalate is c o d e d as T . C D T represents 1 , 4 - c y c l o h e x a n e d i m e t h y l e n e t e r e p h thalate. 4 G T represents t e t r a m e t h y l e n e terephthalate. C o p o l y m e r c o m p o s i t i o n s are expressed as w e i g h t percentages of the ester units w i t h the r e m a i n d e r b e i n g p o l y e t h e r - e s t e r u n i t s . F o r instance, 4 0 % tetramethylene t e r e p h t h a l a t e / P T M E terephthalate copolymer rep resents a b l o c k c o p o l y m e r c o n t a i n i n g 40 w t % of t e t r a m e t h y l e n e t e r e p h thalate units a n d b y difference 60 w t % of p o l y ( t e t r a m e t h y l e n e ether ) terephthalate units. Materials. E x c e p t w h e r e o t h e r w i s e n o t e d the m a t e r i a l s w e r e of c o m m e r c i a l q u a l i t y a n d w e r e u s e d as r e c e i v e d . T h e P T M E g l y c o l u s e d was o b t a i n e d f r o m Ε . I. d u P o n t de N e m o u r s a n d C o . Its n u m b e r - a v e r a g e m o l e c u l a r w e i g h t r a n g e d f r o m 975 to 1020, b a s e d o n h y d r o x y l - n u m b e r determinations ( A S T M D2849-69 ) assuming t w o hydroxyls per molecule. D i m e t h y l terephthalate, 1 , 4 - b u t a n e d i o l , a n d t e t r a b u t y l titanate ( " T y z o r " T B T o r g a n i c titanate ) w e r e o b t a i n e d f r o m Ε . I. d u P o n t de N e m o u r s a n d C o . P r a c t i c a l - g r a d e 1 , 4 - c y c l o h e x a n e d i m e t h a n o l a n d reagent-grade trans1,4-cyclohexanedimethanol were obtained f r o m Eastman K o d a k C o . D i m e t h y l isophthalate was practical-grade material f r o m E a s t m a n K o d a k C o . D i m e t h y l m-terphenyl-4,4"-dicarboxylate, prepared b y W . H . W a t s o n u s i n g a r e p o r t e d p r o c e d u r e ( 2 1 ) , w a s o b t a i n e d f r o m the r e t a i n e d - c h e m i c a l storage at the D u P o n t E x p e r i m e n t a l S t a t i o n . Its s t r u c t u r e was v e r i f i e d b y e l e m e n t a l analysis, m o l e c u l a r w e i g h t d e t e r m i n a t i o n , a n d melting point. Polymer Preparation. T h e p o l y e t h e r - e s t e r c o p o l y m e r s w e r e p r e p a r e d b y t i t a n a t e - e s t e r - c a t a l y z e d , m e l t transesterification of a m i x t u r e of P T M E g l y c o l , the d i m e t h y l ester of a n a r o m a t i c d i a c i d , a n d a d i o l present i n 5 0 - 1 0 0 % m o l a r excess a b o v e the s t o i c h i o m e t r i c a m o u n t r e q u i r e d ( F i g u r e 1 ) . T h e reactions w e r e c a r r i e d out i n the presence of n o m o r e t h a n 1 w t % , b a s e d o n final p o l y m e r , of a n a r o m a t i c - a m i n e o r h i n d e r e d p h e n o l antioxidant. T h e general procedures a n d equipment r e q u i r e d h a v e b e e n r e p o r t e d i n d e t a i l (12). T h e polymerization procedure con sisted of a d d i n g catalyst s o l u t i o n to a n i t r o g e n - b l a n k e t e d m i x t u r e of the


7.

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131

Elastomeric Poly ether-Ester Copolymers 0 0 HODOH + CH 0CArC0CH (EXCESS) I 3

3

+ H+0CH CH CH CH -)r 0H 2

2

2

2

4

1. 150-255°C, TITANATE CATALYST (CH 0H DISTILLS) 3

2. 255 C, 25 212

-7 197

-33 189

Polymer Preprints, ACS

T e a r strength, hardness, a n d m e l t i n g p o i n t increase w i t h i n c r e a s i n g content o f 4 G T i n t h e c o p o l y m e r s . C o m p r e s s i o n set is highest at 3 0 % 4 G T content a n d v i r t u a l l y i d e n t i c a l a b o v e 4 0 % resistance

4GT.

C o m p r e s s i o n set

c a n b e i m p r o v e d b y a n n e a l i n g t h e c o p o l y m e r s at e l e v a t e d

t e m p e r a t u r e (12). N o n e of the c o p o l y m e r s i n this c h a p t e r w e r e a n n e a l e d p r i o r t o testing. Resistance to l o w t e m p e r a t u r e stiffening as m e a s u r e d b y the C l a s h B e r g test b e c o m e s i n c r e a s i n g l y p o o r as t h e c o n c e n t r a t i o n of 4 G T is i n c r e a s e d . T h e glass-transition t e m p e r a t u r e (T ) of the a m o r p h o u s phase s

of these c r y s t a l l i n e - a m o r p h o u s c o p o l y m e r s h a s p r e v i o u s l y b e e n s h o w n to increase w i t h i n c r e a s i n g 4 G T content (12,14).

T h e increases i n T

g

w i t h i n c r e a s e d 4 G T content w e r e a t t r i b u t e d t o h i g h e r concentrations o f u n c r y s t a l l i z e d 4 G T units i n t h e a m o r p h o u s phase

(4,5,14,15),

the

i n c r e a s e d n u m b e r of c r y s t a l l i n e tie p o i n t s (14), a n d the greater r e i n f o r c e m e n t of t h e a m o r p h o u s phase b y t h e on-average-longer 4 G T (15).

segments

Lilaonitkul, West, a n d Cooper have used differential scanning

c a l o r i m e t r y measurements t o relate the percentage of the p o l y e t h e r - e s t e r c o p o l y m e r w h i c h is c r y s t a l l i n e to the t o t a l 4 G T content of t e t r a m e t h y l e n e t e r e p h t h a l a t e / P T M Ε terephthalate c o p o l y m e r s (4,5).

T h e i r results i n d i

cate that f o r c o p o l y m e r s w h i c h h a v e b e e n c o m p r e s s i o n m o l d e d a n d h a v e not b e e n a n n e a l e d , a p p r o x i m a t e l y 3 5 - 5 4 % of t h e t o t a l 4 G T are c r y s t a l l i z e d . T h e percentage

segments

of 4 G T segments w h i c h w e r e f o u n d

to b e c r y s t a l l i n e i n c r e a s e d w i t h i n c r e a s i n g 4 G T content u p t o a b o u t 7 6 % 4 G T i n the c o p o l y m e r .


134

MULTIPHASE POLYMERS

Elongation

at b r e a k

c o p o l y m e r s increases.

decreases as the

4GT

concentration

in

the

P e r m a n e n t set at b r e a k appears to s h o w n o corre

lation w i t h 4 G T concentration.

A c o n s i d e r a b l y different p i c t u r e emerges

i f one calculates p e r m a n e n t set at b r e a k as a p e r c e n t a g e of e l o n g a t i o n at b r e a k a n d plots the result vs. the c o n c e n t r a t i o n of 4 G T i n the c o p o l y m e r s (Figure 2).

A s the c o n c e n t r a t i o n of 4 G T increases, the c o p o l y m e r s s h o w

less a n d less elastic r e c o v e r y u n d e r the c o n d i t i o n s of the set


ments.

measure

T h e greater the 4 G T content, the less elastomeric are the b l o c k

c o p o l y m e r s a n d the m o r e c l o s e l y they re se mb le the ester h o m o p o l y m e r , poly( tetramethylene

terephthalate),

w h i c h is a t o u g h , r a p i d l y c r y s t a l

lizing plastic. Alkylene

Terephthalate/PTME

Terephthalate

Copolymers

T h e s t r u c t u r e of the d i o l i n a l k y l e n e t e r e p h t h a l a t e / P T M E

tereph

thalate c o p o l y m e r s has a n i m p o r t a n t effect o n the p r o p e r t i e s of these b l o c k c o p o l y m e r s , as e v i d e n t f r o m t h e results s h o w n i n T a b l e s II, and IV.

The

50%

tetramethylene

terephthalate/PTME

copolymer prepared f r o m 1,4-butanediol

(4G)

III,

terephthalate

w h i c h was previously

n o t e d i n T a b l e I serves as o u r r e f e r e n c e c o p o l y m e r f o r p u r p o s e s

of

d i s c u s s i n g the effects of c h a n g i n g the s t r u c t u r e of the c r y s t a l l i z a b l e ester segments.

T h e o u t s t a n d i n g p r o p e r t i e s of the 4 G - b a s e d c o p o l y m e r

are

ease of synthesis, a r a p i d rate of c r y s t a l l i z a t i o n f r o m the m e l t , a h i g h m e l t i n g p o i n t , a n d excellent tensile a n d tear strengths. Ethylene

Terephthalate/PTME

Terephtalate

Copolymer.

e t h y l e n e g l y c o l - or 2 G - b a s e d c o p o l y m e r ( T a b l e I I ) c l o s e l y resembles

The the

4 G - b a s e d c o p o l y m e r i n h a v i n g a h i g h m e l t i n g p o i n t , e v e n h i g h e r t h a n the 4 G c o p o l y m e r , a n d excellent tensile a n d tear strengths.

The

copolymer

crystallization

suffers

from having a

rather

s l o w rate

of

2G-based

( 8 , 1 2 ) . P o l y ( e t h y l e n e t e r e p h t h a l a t e ) h o m o p o l y m e r suffers f r o m s i m i l a r Table II.

50%

Alkylene Terephthalate/PTME 2G

Diol C o p o l y m e r properties I n h e r e n t v i s c o s i t y (L/g) Y i e l d strength ( M P a ) Stress a t 1 0 0 % ( M P a ) T e n s i l e strength ( M P a ) E l o n g a t i o n (%) P e r m a n e n t set (%) T e a r strength ( k N / m ) Shore D hardness C o m p r e s s i o n set (%) C l a s h - B e r g Γ ,οοο ( ° C ) Melting point ( ° C ) 10

0.13

—

11.4 45.5 675 275 42 46 52 -38 224

Terephthalate SG 0.17

—

11.7 22.8 660 195 15 48 48 -36 198



7.

WOLFE

Elastomeric Poly ether-Ester Copolymers

Ο

25 50 75 TETRAMETHYLENE TEREPHTHALATE (WT % ) Polymer Preprints, ACS

Figure 2. Permanent set at break as a percentage of elongation at break vs. the wt % of tetramethylene terephthalate segments in tetramethylene terephthalate/PTME terephthalate copoly mers (36)

Copolymers—Properties as a Function of D i o l Structure

(36)

4G

5G

6G

10G

0.18 — 11.7 48.4 755 370 48 48 52 -33 189

0.16 4.8 4.5 15.4 880 210 25 32 90 -50 106

0.15 — 5.2 13.5 750 370 18 33 86 -53 122

0.13 — 6.1 15.5 640 370 7.8 35 81 -51 106


136

MULTIPHASE POLYMERS

T a b l e III. 1,4-Benzenedimethylene T e r e p h t h a l a t e / P T M E Terephthalate C o p o l y m e r s — P r o p e r t i e s as a F u n c t i o n o f 1 , 4 - B e n z e n e d i m e t h y l e n e T e r e p h t h a l a t e C o n t e n t (36)


1,4-Benzenedimethylene (wt%)

Terephthalate

40

80

C o p o l y m e r properties Inherent viscosity (L/g) Stress a t 1 0 0 % ( M P a ) T e n s i l e strength ( M P a ) E l o n g a t i o n (%) P e r m a n e n t set ( % ) T e a r strength ( k N / m ) Shore D hardness C o m p r e s s i o n set (%) Clash-Berg T . oo ( ° C ) M e l t i n g point ( ° C ) 10

0.13 5.9 19.2 628 161 7.7 32 55 -61 199

0

0.11 9.0 21.7 500 160 10.5 40 54 -58

—•

50 0.10 11.7 21.3 380 143 14.4 48 58 -42 227

difficulties w i t h c r y s t a l l i z a t i o n rate ( 2 6 ) . A s l o w rate of c r y s t a l l i z a t i o n severely l i m i t s t h e use of i n j e c t i o n - m o l d i n g t e c h n i q u e s t o f a b r i c a t e i t e m s f r o m these p o l y m e r s . Synthesis of t h e 2 G - b a s e d c o p o l y m e r c a n b e s o m e w h a t m o r e d i f f i c u l t t h a n synthesis of t h e analogous 4 G - b a s e d c o p o l y m e r . g l y c o l a n d d i m e t h y l terephthalate

monomers

If the ethylene

are p r e r e a c t e d

to form

bis ( 2 - h y d r o x y e t h y l ) t e r e p h t h a l a t e , a n d this p r o d u c t is t h e n c o p o l y m e r i z e d w i t h poly(tetramethylene

e t h e r ) g l y c o l to f o r m t h e b l o c k c o p o l y m e r

u s i n g t e t r a b u t y l t i t a n a t e as t h e transesterification catalyst, t h e r e a c t i o n proceeds

r e a d i l y a n d c o p o l y m e r of h i g h

i n h e r e n t v i s c o s i t y is easily

o b t a i n e d . I f t h e e t h y l e n e g l y c o l m o n o m e r is n o t p r e r e a c t e d a n d t e t r a b u t y l titanate is a g a i n u s e d as t h e transesterification catalyst, t h e c o p o l y m e r i z a tion proceeds more slowly a n d a block copolymer of lower inherent v i s c o s i t y is u s u a l l y o b t a i n e d . Table I V .

1,4-Cyclohexanedimethylene T e r e p h t h a l a t e / P T M E of 1,4-Cyclohexanedimethylene

1,4-Cyclohexanedimethylene Terephthalate (wt fo) C o p o l y m e r properties Inherent viscosity ( L / g ) Stress a t 1 0 0 % ( M P a ) T e n s i l e strength ( M P a ) E l o n g a t i o n (%) P e r m a n e n t set ( % ) T e a r strength ( k N / m ) Shore D hardness C o m p r e s s i o n set (%) C l a s h - B e r g Γ ,οοο ( ° C ) 10


7.

WOLFE

137


Trimethylene Terephthalate/PTME Terephthalate Copolymer. T h e properties

of the 1,3-propanediol- or 3G-based

c o p o l y m e r a r e rather

s u r p r i s i n g . T h e m e l t i n g p o i n t a n d t h e stress at 1 0 0 % e l o n g a t i o n of this c o p o l y m e r are v e r y s i m i l a r to those of the 2 G - a n d 4 G - b a s e d c o p o l y m e r s , yet t h e 3 G - b a s e d c o p o l y m e r has m u c h l o w e r tensile strength at b r e a k a n d v e r y l o w tear strength. unknown. Downloaded by UCSF LIB CKM RSCS MGMT on November 19, 2014 | http://pubs.acs.org Publication Date: June 1, 1979 | doi: 10.1021/ba-1979-0176.ch007

which

T h e cause of these w i d e differences

P o s s i b l y r e l a t e d are studies c a r r i e d o u t o n o r i e n t e d

have s h o w n that

t h e c r y s t a l l i n e regions

is

fibers

of p o l y ( t r i m e t h y l e n e

terephthalate ) h o m o p o l y m e r r e s p o n d q u i t e d i f f e r e n t l y t o s t r a i n - i n d u c e d d e f o r m a t i o n t h a n d o t h e c r y s t a l l i n e regions of p o l y ( e t h y l e n e ate) or poly ( tetramethylene

terephthalate ) h o m o p o l y m e r s

5 G - , 6 G - , a n d 10G-Based Copolymers. PTME

terephthalate

T h e alkylene terephthalate/

c o - p o l y m e r s b a s e d o n 1,5-pentanediol

h e x a n e d i o l ( 6 G ) , a n d 1,10-decanediol

terephthal(17). ( 5 G ) , 1,6-

( 1 0 G ) resemble e a c h other m o r e

c l o s e l y t h a n they d o those p r e p a r e d f r o m t h e shorter d i o l s . T h e c o p o l y mers p r e p a r e d f r o m these l o n g e r diols a l l s h o w , r e l a t i v e t o those c o p o l y mers p r e p a r e d f r o m shorter d i o l s , l o w m e l t i n g p o i n t , l o w hardness, h i g h c o m p r e s s i o n set, l o w stress a t 1 0 0 % e l o n g a t i o n , a n d l o w tensile strength. T h e tear strengths of t h e 5 G - , 6 G - , a n d 1 0 G - b a s e d c o p o l y m e r s are also l o w r e l a t i v e to t h e 2 G - a n d 4 G - b a s e d c o p o l y m e r s .

The 5G-, 6G-, and

1 0 G - b a s e d c o p o l y m e r s excel i n t h e i r resistance to s t i f f e n i n g at l o w t e m peratures as m e a s u r e d b y t h e C l a s h - B e r g test. It s h o u l d b e n o t e d that the c o p o l y m e r s p r e p a r e d f r o m the l o n g e r d i o l s c o n t a i n a l o w e r m o l e f r a c t i o n of h a r d segments t h a n d o the c o p o l y m e r s p r e p a r e d f r o m t h e shorter d i o l s . A p l o t of t h e o b s e r v e d m e l t i n g points of t h e 5 0 % a l k y l e n e t e r e p h t h a l a t e / P T M E terephthalate c o p o l y m e r s v s . t h e r a n g e o f m e l t i n g points of t h e p o l y ( a l k y l e n e terephthalate ) h o m o p o l y m e r s as t a k e n f r o m t h e l i t e r a t u r e (16,18-25) results i n t h e l i n e a r r e l a t i o n s h i p s h o w n i n F i g u r e 3 . Terephthalate Terephthalate

C o p o l y m e r s — P r o p e r t i e s as a F u n c t i o n Structure and Concentration trans-CD

Practical CD 20

30

0.12 2.6 5.9 625 118 3.2 15 75 -55

0.12 6.2 11.0 470 119 6.0 34 62 -60

40

50

0.11 — 8.1 40 5 10.2 42 53 -53

brittle

20

30

0.13 4.1 6.8 280 47 4.6 24 60 -58

insol

brittle


138

MULTIPHASE POLYMERS


240

120

160

HOMOPOLYMER

200

240

MELTING POINT (°C)

280

Figure 3. The melting points of 50% alkylene terephthalate/FTME terephthalate copolymers as a function of the melting points of the corresponding poly(alkylene terephthalate) homopolymers A least-squares fit o f t h e d a t a u s i n g t h e center o f t h e r a n g e o f m e l t i n g points reported for the homopolymers p r o v i d e d the relationship: m p ( c o p o l y m e r ) = 0.94 m p ( h o m o p o l y m e r ) — 17 1,4-Benzenedimethylene polymers.

The

50%

Terephthalate/PTME

1,4-benzenedimethylene

(2)

Terephthalate C o terephthalate/PTME

t e r e p h t h a l a t e c o - p o l y m e r of T a b l e I I I has a h i g h stress at 1 0 0 % e l o n g a t i o n c o m p a r a b l e t o t h e 2 G - a n d 4 G - b a s e d c o p o l y m e r s o f T a b l e I I b u t is l o w in

i n h e r e n t v i s c o s i t y , tensile

strength,

elongation

at b r e a k ,

a n d tear

strength. T h e p o o r f a i l u r e p r o p e r t i e s o f t h e 1 , 4 - b e n z e n e d i m e t h a n o l - b a s e d c o p o l y m e r c a n b e a t t r i b u t a b l e i n p a r t to t h e l o w m o l e c u l a r w e i g h t o f t h e c o - p o l y m e r as i n d i c a t e d b y its l o w i n h e r e n t v i s c o s i t y .

T h e tensile

strengths at b r e a k of s i m i l a r 4 G - b a s e d c o p o l y m e r s h a v e b e e n s h o w n to decrease as t h e i r i n h e r e n t viscosities a r e r e d u c e d 1,4-Cyclohexanedimethylene Copolymers.

Polyether-ester

(12).

Terephthalate/PTME

copolymers

based

Terephthalate

o n 1,4-cyclohexanedi-

methanol have been prepared using both irans-l,4-cyclohexanedimethanol ( t-CD ) a n d a p r a c t i c a l g r a d e

of 1 , 4 - c y c l o h e x a n e d i m e t h a n o l

(p-CD)

w h i c h is r e p o r t e d t o c o n t a i n a b o u t a 68/32 m i x t u r e o f trans- t o m - 1 , 4 c y c l o h e x a n e d i m e t h a n o l (26).

G a s - p h a s e c h r o m a t o g r a p h y o f o n e of o u r

samples o f p - C D i n d i c a t e d a 72/28 ratio of trans-to-cis i s o m e r .


B y use

7.

WOLFE

of

p r a c t i c a l grade,

139

Elastomeric Poly ether-Ester Copolymers 1,4-cyclohexanedimethanol,

copolymers

could

be

p r e p a r e d c o n t a i n i n g 20 a n d 3 0 % of 1 , 4 - c y c l o h e x a n e d i m e t h y l e n e t e r e p h thalate ( p - C D ) units w h o s e stress at 1 0 0 % e l o n g a t i o n , tensile strength, tear strength, content

a n d Shore

(Table

D hardness

increase

I V ) . At 40% p-CDT

with

content,

increasing C D T

tensile s t r e n g t h a n d

e l o n g a t i o n at b r e a k of t h e c o p o l y m e r d r o p off f r o m t h e values o b t a i n e d w i t h the 3 0 % p - C D T c o p o l y m e r b e c a u s e of phase s e p a r a t i o n i n t h e m e l t


d u r i n g t h e synthesis of t h e 4 0 % p - C D T c o p o l y m e r . Phase s e p a r a t i o n d u r i n g t h e synthesis

of t h e 5 0 % p - C D T

c o p o l y m e r w a s sufficiently

severe that the r e s u l t i n g c o p o l y m e r w a s a b r i t t l e s o l i d rather t h a n a n elastomer.

W h e n £rans-l,4-cyelohexanedimethanol

is u s e d as t h e d i o l

m o n o m e r , severe phase s e p a r a t i o n d u r i n g c o p o l y m e r i z a t i o n occurs at e v e n l o w e r levels of C D T t h a n w h e n u s i n g p r a c t i c a l - g r a d e 1,4-cyclohexanedi methanol.

T h e 3 0 % ί - C D T c o p o l y m e r resembles t h e 5 0 % p - C D T co

p o l y m e r i n that i t is n o t elastomeric b u t b r i t t l e ( T a b l e I V ) . Phase s e p a r a t i o n d u r i n g m e l t c o p o l y m e r i z a t i o n w a s r e p o r t e d i n t h e first p a p e r of this series, p a r t i c u l a r l y w i t h t e t r a m e t h y l e n e poly (propylene

oxide)

terephthalate

copolymers

terephthalate/

prepared

from the

h i g h e r m o l e c u l a r w e i g h t p o l y e t h e r g l y c o l s ( 1 0 ) . P h a s e s e p a r a t i o n occurs d u r i n g t h e p r e p a r a t i o n of p o l y e t h e r - e s t e r c o p o l y m e r s w h e n t h e c o p o l y m e r i z a b l e segments are m u t u a l l y i n s o l u b l e i n e a c h other. T h e result is a r e a c t i o n m i x t u r e c o n t a i n i n g t w o phases, as o f t e n e v i d e n c e d b y t h e m e l t having

an opaque

appearance.

rather

than

t h e u s u a l transparent

or translucent

A s n o t e d i n t h e p r e v i o u s p a p e r (10) a n d as s h o w n i n T a b l e

I V , severe phase s e p a r a t i o n results i n c o p o l y m e r s w h i c h

exhibit l o w

e l o n g a t i o n at b r e a k a n d v e r y often l o w tensile a n d tear strengths. T h e c o n c l u s i o n that t h e v e r y l o w e l o n g a t i o n at b r e a k of the 4 0 % p - C D T c o p o l y m e r ( T a b l e I V ) is c a u s e d b y phase s e p a r a t i o n d u r i n g c o p o l y m e r i z a t i o n is s u p p o r t e d b y t h e o b s e r v a t i o n that t h e p o l y m e r i z i n g m e l t of t h e 40%

p-CDT

c o p o l y m e r w a s o p a q u e w h i l e that of t h e 3 0 %

p-CDT

c o p o l y m e r w a s transparent. T h e r e a r e several t e c h n i q u e s a v a i l a b l e to h e l p o v e r c o m e t h e p r o b l e m of phase s e p a r a t i o n d u r i n g m e l t c o p o l y m e r i z a t i o n . O n e t e c h n i q u e is t o a d d a h i g h - b o i l i n g solvent to t h e p o l y m e r i z a t i o n m e l t to assist i n s o l u b i l i z i n g the c o p o l y m e r i z i n g segments. A s e c o n d t e c h n i q u e is to i n t r o d u c e other m o n o m e r s i n t o t h e c o p o l y m e r i z a t i o n s u c h as a s e c o n d d i o l , a second ester ( 2 7 ) , o r b o t h . T h e a d d i t i o n a l m o n o m e r s serve to l o w e r t h e c o n c e n t r a t i o n a n d m e l t i n g p o i n t of a n y h a r d segment w h i c h m i g h t t e n d t o separate out. T h e use of p r a c t i c a l - g r a d e 1 , 4 - c y c l o h e x a n e d i m e t h a n o l w h i c h contains b o t h t h e cis a n d trans isomers rather t h a n u s i n g p u r e trans-1,4c y c l o h e x a n e d i m e t h a n o l is a m e t h o d of a d d i n g a s e c o n d d i o l w h i l e s i m u l taneously l o w e r i n g t h e c o n c e n t r a t i o n of t h e first d i o l .

T h e effectiveness

of this m e t h o d is e v i d e n t f r o m t h e results s h o w n i n T a b l e I V . A 3 0 %


140

MULTIPHASE POLYMERS

1,4-cyclohexanedimethylene

t e r e p h t h a l a t e / P T M E terephthalate

copoly

mer could be prepared using practical-grade 1,4-cyclohexanedimethanol whereas

the

analogous

copolymer based

on

frans-1,4-cyclohexanedi

m e t h a n o l u n d e r w e n t severe phase s e p a r a t i o n i n t h e m e l t d u r i n g synthesis.


Alkylene Ester/PTME Ester Copolymers Other Than Terephthalate Ester Up

to this p o i n t the d i s c u s s i o n has b e e n c o n c e r n e d w i t h a l k y l e n e

t e r e p h t h a l a t e / P T M E t e r e p h t h a l a t e c o p o l y m e r s i n w h i c h the c o n c e n t r a t i o n of a l k y l e n e t e r e p h t h a l a t e

a n d t h e c h e m i c a l s t r u c t u r e of the

groups have been varied.

T h e next s e c t i o n of this r e p o r t is c o n c e r n e d

w i t h polyether-ester terephthalate diols.

c o p o l y m e r s i n w h i c h a r o m a t i c esters o t h e r

are u s e d i n c o m b i n a t i o n w i t h P T M E

T h e objective

alkylene

is t h e same,

to correlate

than

glycol a n d various

changes i n c o p o l y m e r

s t r u c t u r e w i t h changes i n c o p o l y m e r i z a t i o n results a n d c o p o l y m e r p r o p e r ties.

O n c e a g a i n the 5 0 %

tetramethylene t e r e p h t h a l a t e / P T M E tereph

thalate c o p o l y m e r ( T a b l e s I a n d I I )

w i t h its e x c e l l e n t p r o p e r t i e s a n d

r e l a t i v e ease of synthesis w i l l b e u s e d as the p o i n t of r e f e r e n c e to w h i c h the other p o l y m e r s w i l l b e c o m p a r e d . A l k y l e n e I s o p h t h a l a t e / P T M E Isophthalate Copolymers. Polyetherester c o p o l y m e r s h a v i n g t h e c o m p o s i t i o n s 5 0 %

alkylene isophthalate/

P T M E i s o p h t h a l a t e w e r e p r e p a r e d u s i n g as d i o l s e t h y l e n e

glycol

1,4-butanediol ( 4 G ) , practical-grade 1,4-cyclohexanedimethanol and £rans-l,4-cyclohexanedimethanol 2G-based

copolymer, w h i c h

was

(t-CD)

as s h o w n i n T a b l e V .

prepared using

(2G),

(p-CD), The

bis ( 2-hydroxyethyl )

i s o p h t h a l a t e , h a d n o d i s c e r n i b l e m e l t i n g p o i n t as m e a s u r e d b y d i f f e r e n t i a l scanning calorimetry.

It e x h i b i t e d l o w hardness, l o w stress at

100%

e l o n g a t i o n , a n d v e r y l o w tensile s t r e n g t h . A p p a r e n t l y the e t h y l e n e i s o p h Table V .

50%

A l k y l e n e I s o p h t h a l a t e / P T M E Isophthalate

Diol

2G

C o p o l y m e r properties Inherent v i s c o s i t y ( L / g ) Stress a t 1 0 0 % ( M P a ) T e n s i l e strength ( M P a ) E l o n g a t i o n (%) P e r m a n e n t set (%) T e a r strength ( k N / m ) Shore D hardness C o m p r e s s i o n set (%) C l a s h - B e r g Γ ,οοο ( ° C ) M e l t i n g point ( C ) 10

0.16 0.7 < 0.7 > 1000 > 470 — 7 — -37 none


7.

WOLFE

thalate

141


segments d i d n o t c r y s t a l l i z e , e v e n t h o u g h t h e h o m o p o l y m e r

p o l y ( e t h y l e n e i s o p h t h a l a t e ) is r e p o r t e d t o h a v e a m e l t i n g p o i n t i n t h e r a n g e 1 0 2 ° - 2 4 0 ° C (20,23,28).

A n n e a l i n g this p o l y e t h e r - e s t e r c o p o l y m e r

a b o v e t h e glass-transition t e m p e r a t u r e o f p o l y ( e t h y l e n e

isophthalate )

m i g h t p o s s i b l y i n d u c e some c r y s t a l l i z a t i o n o f ester segments a l t h o u g h this w a s not a t t e m p t e d . The 50%

tetramethylene i s o p h t h a l a t e / P T M E isophthalate copoly-


m e r l i s t e d u n d e r 4 G i n T a b l e V exhibits o u t s t a n d i n g tensile s t r e n g t h a n d excellent tear strength even t h o u g h this c o p o l y m e r is c o n s i d e r a b l y l o w e r i n m e l t i n g p o i n t , Shore hardness, a n d stress a t 1 0 0 % the analogous 5 0 %

tetramethylene

e l o n g a t i o n t h a n is

terephthalate/PTME

terephthalate

c o p o l y m e r of T a b l e s I a n d I I . I n contrast t o t h e t e r e p h t h a l a t e - b a s e d c o p o l y m e r w h i c h crystallizes a n d hardens i n seconds, t h e 5 0 %

tetra-

m e t h y l e n e i s o p h t h a l a t e / P T M E isophthalate c o p o l y m e r crystallizes v e r y s l o w l y o v e r a p e r i o d of hours. T h e i s o p h t h a l a t e - b a s e d c o p o l y m e r exhibits a d o u b l e e n d o t h e r m b y d i f f e r e n t i a l s c a n n i n g c a l o r i m e t r y w i t h peaks at 85° and 112°C.

T h e 8 5 ° C p e a k is s l i g h t l y the larger o f the t w o .

Poly-

( t e t r a m e t h y l e n e i s o p h t h a l a t e ) h o m o p o l y m e r has r e p o r t e d m e l t i n g p o i n t s of 8 8 ° - 1 5 2 ° C

(20,28).

F i f t y percent 1,4-cyclohexanedimethylene i s o p h t h a l a t e / P T M E isophthalate c o p o l y m e r s p r e p a r e d f r o m p r a c t i c a l - g r a d e 1 , 4 - c y c l o h e x a n e d i m e t h a n o l a n d f r o m trans- 1 , 4 - c y c l o h e x a n e d i m e t h a n o l also h a r d e n s l o w l y o v e r a p e r i o d o f h o u r s . N o attempts w e r e m a d e t o s p e e d the rate o f c r y s t a l l i z a t i o n of these c o p o l y m e r s b y a d d i t i o n of n u c l e a t i n g agents a l t h o u g h i t has b e e n d e m o n s t r a t e d that t h e rate o f c r y s t a l l i z a t i o n o f e t h y l e n e t e r e p h t h a l a t e / P T M E t e r e p h t h a l a t e c o p o l y m e r s , w h i c h also c r y s t a l l i z e s l o w l y , can b e increased b y nucleation. U n l i k e t h e i r terephthalate analogs o f T a b l e I V , the

1,4-cyclohexane-

dimethylene i s o p h t h a l a t e / P T M E isophthalate copolymers show n o e v i Copolymers—Properties as a Function of D i o l Structure ( 3 6 ) 4G 0.16 7.2 58.6 720 126 54 39 91 -31 85,112

Practical 0.14 5.7 31.7 690 70 78 38 89 -38 147

CD

trans-CD 0.11 6.9 33.8 760 179 61 46 87 -28 184 Polymer Preprints, ACS



142

MULTIPHASE

POLYMERS

d e n c e of phase separation d u r i n g c o p o l y m e r i z a t i o n . T h e difference i n b e h a v i o r d u r i n g synthesis m a y b e c a u s e d b y t h e l o w e r m e l t i n g points of t h e isophthalate c o p o l y m e r s . P o l y ( £rans-l,4-cyclohexanedimethylene i s o p h t h a l a t e ) h o m o p o l y m e r is r e p o r t e d t o h a v e a m e l t i n g range of 1 9 0 ° 197 ° C w h i l e p o l y (trans- 1,4-cyclohexanedimethylene t e r e p h t h a l a t e ) has a m e l t i n g range of 312°-318°C (29). T h i s suggests that i f t h e 1,4-cycloh e x a n e d i m e t h y l e n e t e r e p h t h a l a t e / P T M E terephthalate c o p o l y m e r i z a t i o n s c o u l d b e r u n at h i g h e r temperatures, phase separation i n t h e m e l t m i g h t b e less of a p r o b l e m . U n f o r t u n a t e l y h i g h e r p o l y m e r i z a t i o n temperatures w o u l d increase t h e rate of p o l y m e r d e g r a d a t i o n w h i c h is k n o w n to o c c u r at a significant rate even at t h e m e l t temperatures u s e d i n t h e p r e p a r a t i o n of t h e c o p o l y m e r s d e s c r i b e d i n this r e p o r t (13,30). ( T w o o f t h e three curves i n F i g u r e 7 of R e f . 13 are m i s l a b e l e d . T h e " P o l y t e t r a m e t h y l e n o x i d " a n d " P o l y p r o p y l e n o x i d " labels s h o u l d b e r e v e r s e d (31).)

Alkylene 4,4'-Biphenyldicarboxylate/PTjME 4,4'-Biphenyldicarboxylate Copolymers. T e t r a m e t h y l e n e 4 , 4 ' - b i p h e n y l d i c a r b o x y l a t e / P T M E 4,4 -biphenyldicarboxylate c o p o l y m e r s c o n t a i n i n g 20 a n d 3 0 % tetram e t h y l e n e 4,4'-biphenyldicarboxylate w e r e p r e p a r e d w i t h o u t i n c i d e n t ( T a b l e V I ) . A t t e m p t s to p r e p a r e s i m i l a r c o p o l y m e r s c o n t a i n i n g 40 a n d 50% tetramethylene 4,4'-biphenyldicarboxylate l e d t o p r o b l e m s w i t h phase separation i n the m e l t d u r i n g t h e c o p o l y m e r i z a t i o n s . /

F i f t y p e r c e n t 4 , 4 ' - b i p h e n y l d i c a r b o x y l a t e / P T M E 4,4'-biphenyldicarb o x y l a t e c o p o l y m e r s w e r e p r e p a r e d u s i n g 1,3-propanediol (3G), 1,5p e n t a n e d i o l ( 5 G ) , a n d 1,6-hexanediol (6G) ( T a b l e V I I ) . A l l w e r e p r e p a r e d w i t h o u t i n c i d e n t . T h e 3G-based c o p o l y m e r has p o o r tear strength. T h e 5G-based c o p o l y m e r has g o o d tear strength b u t l o w tensile strength at break. T h e 6G-based c o p o l y m e r has t h e best tensile strength of t h e three c o p o l y m e r s b u t has l o w tear strength.

Table V I . Tetramethylene 4,4'-Biphenyldicarboxylate/PTME 4,4'-Biphenyldicarboxylate Copolymers—Properties as a Function of Tetramethylene 4,4'-Biphenyldicarboxylate Concentration Tetramethylene 4A'-biphenyldicarboxylate (wt %) C o p o l y m e r properties Inherent v i s c o s i t y ( L / g ) Stress a t 1 0 0 % ( M P a ) T e n s i l e strength ( M P a ) E l o n g a t i o n (%) P e r m a n e n t set (%) T e a r strength ( k N / m ) Shore D hardness C o m p r e s s i o n set (%) C l a s h - B e r g r .ooo C O 10

20

30

0.20 2.8 9.7 1050 283 5 22 65 -59

0.21 5.5 10.3 600 175 20 33 49 -58

40 insol


8.0 8.3 200 69 10 32 67

7.

WOLFE

143


Table V I I . 50% Alkylene 4,4'-Biphenyldicarboxylate/PTME 4,4'-Biphenyldicarboxylate Copolymers—Properties as a Function of Diol Structure


C o p o l y m e r properties Inherent viscosity (L/g) Stressât 100% ( M P a ) T e n s i l e strength ( M P a ) E l o n g a t i o n (%) P e r m a n e n t set (%) T e a r strength ( k N / m ) Shore D hardness C o m p r e s s i o n set (%) C l a s h - B e r g T ,ooo ( ° C ) 10

Alkylene

5G

3G

Diol

0.12 9.8 11.0 560 190 11 50 61 -40

0.12 5.5 7.6 490 191 40 35 82 -40

2,6-Naphthalenedicarboxylate/PTME

dicarboxylate Copolymers. F i f t y percent a l k y l e n e b o x y l a t e / P T M E 2,6-naphthalenedicarboxylate

6G 0.13 7.8 15.2 510 329 16 40 67 -35

2,6-Naphthalene-

2,6-naphthalenedicar-

copolymers were prepared

u s i n g e a c h of the s t r a i g h t - c h a i n , h y d r o x y - t e r m i n a t e d d i o l s f r o m ethylene g l y c o l ( 2 G ) to 1,10-decanediol ( 1 0 G ) ( T a b l e V I I I ) .

I n contrast to m a n y

of t h e 5 0 % a l k y l e n e t e r e p h t h a l a t e / P T M E terephthalate T a b l e I I , a l l of t h e 2 , 6 - n a p h t h a l e n e d i c a r b o x y l a t e - b a s e d

c o p o l y m e r s of

c o p o l y m e r s tested

e x h i b i t excellent tensile strength a n d tear strength regardless of t h e d i o l u s e d o r t h e m e l t i n g p o i n t of the c o p o l y m e r . A s a c o n s e q u e n c e of t h e i r excellent properties, t h e 2 , 6 - n a p h t h a l e n e d i c a r b o x y l a t e

copolymers

have

b e e n t h e subject of several patents ( 3 2 , 3 3 , 3 4 ) . P e r m a n e n t set values are r e l a t i v e l y h i g h f o r the 2 , 6 - n a p h t h a l e n e d i c a r b o x y l a t e c o p o l y m e r s p r e p a r e d f r o m diols c o n t a i n i n g a n e v e n n u m b e r of c a r b o n atoms b u t q u i t e l o w f o r the c o r r e s p o n d i n g c o p o l y m e r s p r e p a r e d f r o m o d d - m e m b e r e d d i o l s , p a r t i c u l a r l y the 3 G , 5 G , a n d 7 G d i o l s . S t r a i n i n d u c e d i r r e v e r s i b l e d i s r u p t i o n a n d o r i e n t a t i o n of c r y s t a l l i n e ester segments has b e e n a d v a n c e d as t h e cause o f t h e h i g h p e r m a n e n t

sets of

tetramethylene t e r e p h t h a l a t e / P T M E terephthalate c o p o l y m e r s (14).

On

this basis t h e c r y s t a l l i n e ester segments of t h e 2 , 6 - n a p h t h a l e n e d i c a r b o x y l ate c o p o l y m e r s p r e p a r e d f r o m o d d - m e m b e r e d d i o l s a p p e a r to b e c o n s i d e r a b l y m o r e resistant t o s t r a i n - i n d u c e d i r r e v e r s i b l e d e f o r m a t i o n t h a n d o t h e c r y s t a l l i n e segments of t h e c o r r e s p o n d i n g c o p o l y m e r s from even-membered

diols.

prepared

T h i s i n t u r n suggests t h e presence of a

persistent p a t t e r n of m o r p h o l o g i c a l differences b e t w e e n t h e c r y s t a l l i n e ester segments d e r i v e d f r o m t h e e v e n - m e m b e r e d d i o l s a n d those d e r i v e d f r o m the odd-membered diols. A p l o t of t h e m e a s u r e d m e l t i n g points of t h e 5 0 % a l k y l e n e 2,6naphthalenedicarboxylate/PTME

2,6-naphthalenedicarboxylate

copoly-

mers of T a b l e V I I I v s . t h e r e p o r t e d m e l t i n g p o i n t s of t h e c o r r e s p o n d i n g


144

MULTIPHASE POLYMERS

Table VIII.

50%

Alkylene

2,6-Naphthalenedicarboxylate/PTME Function of Diol


Diol C o p o l y m e r properties Inherent viscosity (L/g) Y i e l d strength ( M P a ) Stress at 1 0 0 % ( M P a ) T e n s i l e strength ( M P a ) E l o n g a t i o n (%) P e r m a n e n t set (%) T e a r strength ( k N / m ) Shore D hardness C o m p r e s s i o n set (%) C l a s h - B e r g Γ ,οοο ( ° C ) M e l t i n g point ( ° C ) 10

2G

3G

4G

0.11 — 6.2 35.9 460 102 151 53 67 1 232

0.17 — 7.3 54.5 525 16 79 47 88 -15 168

0.15 — 10.0 51.0 660 280 117 49 49 -14 202

p o l y ( a l k y l e n e - 2 , 6 - n a p h t h a l e n e d i c a r b o x y l a t e ) h o m o p o l y m e r s ( 2 2 ) results i n t h e l i n e a r r e l a t i o n s h i p s h o w n i n F i g u r e 4. A least squares fit of t h e data p r o v i d e d the relationship:

m p ( c o p o l y m e r ) = 0.87 m p ( h o m o p o l y m e r ) — 4.3 240

200

1

I

I

I

1

1

1

I

/

-

"

/€>4G

/ 3G ^ 0

Lil

160 y©8G

yj

l O G ^ /

Ο û.

^Γ

120

ο ο

76 -

80

/

e

9 G

I

120

1

I

1 200

I

160

HOMOPOLYMER

MELTING

1

1

240

i

280

POINT (°C)

Figure 4. The melting points of 50% alkylene 2,6-naphthalenedicarboxyfote/FTME 2 6-naphthalenedicarboxyhte copolymers as a function of the melting points of the corre sponding poly(alkylene 2,6-naphthalenedicarboxylate) ho mopolymers f


(3)

7.

WOLFE

145

Elastomeric Îoly ether-Ester Copolymers

2,6-Naphthalenedicarboxylate Copolymers—Properties as a Structure (36)


5G

6G

0.18 7.4 6.8 52.1 590 65 123 45 94 -5 108

7G

0.20

8G

0.20 7.6 6.8 51.7 540 60 103 49 93 -8 113

8.8 51.0 570 253 123 47 67 -24 176

10G

9G

0.17 6.6 6.4 36.9 620 318 93 41 85 -27 125

0.15

0.20 8.1 7.9 44.1 620 288 82 48 73 -29 149

3.7 38.6 625 147 69 37 99 -34 101

Polymer Preprints, ACS

T h e m e l t i n g points o f t h e 2 , 6 - n a p h t h a l e n e d i c a r b o x y l a t e

homopolymers

a n d their corresponding copolymers

units show a

distinct o d d - e v e n alternation. are

consistently

neighbors.

somewhat

containing P T M E

Polymers based o n odd-membered diols

lower melting than

their

even-membered

T h i s t y p e of b e h a v i o r has b e e n n o t e d f o r other series o f

polyesters a n d has b e e n a t t r i b u t e d t o " a consistent p a t t e r n of c o n f i g u r a t i o n a l a n d c h a i n - p a c k i n g differences

between

o d d a n d even

members

i n h o m o l o g o u s series" ( 2 2 ) . T h u s b o t h t h e m e l t i n g points a n d t h e p e r m a nent sets o f t h e a l k y l e n e 2 , 6 - n a p h t h a l e n e d i c a r b o x y l a t e / P T M E thalenedicarboxylate suggest that

copolymers

consistent

show

differences

patterns

2,6-naph-

of alteration

i n m o r p h o l o g y exist

which

between the

c r y s t a l l i n e ester segments d e r i v e d f r o m t h e e v e n - m e m b e r e d

diols a n d

those d e r i v e d f r o m t h e o d d - m e m b e r e d diols. A p l o t of compression-set the

5 0 % alkylene

Table

results v s . c o p o l y m e r m e l t i n g points f o r

terephthalate/PTME

II a n d the 5 0 % alkylene

2,6-naphthalenedicarboxylate

terephthalate

copolymers of

2,6-naphthalenedicarboxylate/PTME

copolymers of Table

VIII

indicates

that

c o m p r e s s i o n set g e n e r a l l y increases as c o p o l y m e r m e l t i n g p o i n t decreases ( F i g u r e 5 ) . T h i s is n o t s u r p r i s i n g as t h e l o w e r the m e l t i n g p o i n t o f t h e c o p o l y m e r , t h e closer t h e m e l t i n g p o i n t is to t h e 7 0 ° C t e m p e r a t u r e at w h i c h t h e c o m p r e s s i o n set test is r u n a n d thus t h e m o r e s u s c e p t i b l e a r e the c r y s t a l l i n e h a r d segments t o d i s t o r t i o n . T h i s is p a r t i c u l a r l y true o f the c o p o l y m e r s m e l t i n g close to 1 0 0 ° C .

T h e reported m e l t i n g points

represent o n l y t h e peaks o f the e n d o t h e r m i c m e l t i n g curves as m e a s u r e d b y differential scanning calorimetry.

T h e m e l t i n g curves o f t e n c o v e r a

r a n g e o f temperatures as w i d e as 2 0 ° C o n e a c h side o f t h e m e l t i n g - c u r v e peaks.

T h u s t h e l o w e r e n d o f the m e l t i n g ranges o f these l o w - m e l t i n g



146

MULTIPHASE POLYMERS

40 100 1

140 COPOLYMER

180

220

260

MELTING POINT (°C)

Figure 5. Copolymer compression set as a function of copolymer melting point for 5 0 % alkylene ester/PTME ester copolymers (Δ = terephthalate; Ο = 2,6~naphtha~ lene-dicarboxylate )

c o p o l y m e r s m a y l i e v e r y close to t h e 7 0 ° C t e m p e r a t u r e of t h e c o m p r e s s i o n set test. Alkylene

w-Terphenyl-4,4''-dicarboxylate/PTME

4,4"-dicarboxylate Copolymers.

Polyether-ester

w-Terphenyl-

copolymers

w i t h the

composition 5 0 % alkylene m-terphenyl-4,4"-dicarboxylate/PTME

ra-ter-

p h e n y l - 4 , 4 " - d i c a r b o x y l a t e w e r e p r e p a r e d u s i n g as d i o l s 1 , 3 - p r o p a n e d i o l ( 3 G ) a n d 1 , 4 - b u t a n e d i o l ( 4 G ) . B o t h c o p o l y m e r s e x h i b i t excellent tensile a n d tear s t r e n g t h as s h o w n i n T a b l e

I X . T h e y b o t h have very poor

resistance to c o m p r e s s i o n set. After compression m o l d i n g , b o t h copolymers were initially parent.

trans

G r a d u a l l y o v e r a p e r i o d o f m a n y days t h e 4 G - b a s e d c o p o l y m e r

t u r n e d o p a q u e as i f i t w e r e c r y s t a l l i z i n g ( 3 5 ) . T h e 3 G - b a s e d c o p o l y m e r


7.

W O L F E


147


Table I X . 50% Alkylene f»-Terphenyl-4,4"-dicarboxylate/PTME w-Terphenyl-4,4"-dicarboxylate Copolymers °—Properties as a Function of Diol Structure (36) Diol

8G

4G

C o p o l y m e r properties Inherent viscosity (L/g) Stress at 100% (MPa) T e n s i l e strength ( M P a ) E l o n g a t i o n (%) P e r m a n e n t set (%) T e a r strength ( k N / m ) Shore A hardness Shore D hardness C o m p r e s s i o n set ( % ) C l a s h - B e r g Γ ,οοο ( ° C )

0.15 5.7 56.2 420 15 98 94 43 100+ 8

0.17 2.8 60.3 390 3 47 76 31 100+ 2

10

Ο

• m-Terphenyl-4,4"-dicarboxylate =

Ο

—O—C-^^fj^

Elastomeric Polyether-Ester Block Copolymers - ACS Publications

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