Multiphase Polymers - American Chemical Society

8 Phase Separation and Mechanical Properties of an Amorphous Poly(ether-b-ester) M . P. C . W A T T S

1

and E . F. T . W H I T E

Downloaded by UNIV OF ARIZONA on October 2, 2015 | http://pubs.acs.org Publication Date: June 1, 1979 | doi: 10.1021/ba-1979-0176.ch008

Department of Polymer and Fibre Science, University of Manchester, Institute of Science and Technology, Manchester, England

The dynamic mechanical properties and phase separation of a series of amorphous condensation multiblock polymers, poly(oxypropylene-b-oxypropylene studied.

oxyterephthaloyl),

Samples prepared from poly(oxypropylene)

was

with a

molecular weight of 3000 showed clear evidence of block phase separation from small angle x-ray scattering and two transition regions in torsional braid analysis. As the molec ular weight of the poly(oxypropylene)

was reduced, the

stages between clear phase separation and formation of a homogeneous mixture were observed. The size and shape of the mechanical damping peaks could be controlled by the block size, the weight fractions of the two components, and the chemical composition of the components.

T ) o l y m e r s are often used i n sound absorption a n d vibration d a m p i n g a p p l i c a t i o n s ( I ) , f o r e x a m p l e , i n r e d u c i n g h u l l noise i n ships (2) a n d i n s o u n d - p r o o f helmets

( 3 ) . T h e i r efficiency

i n these a p p l i c a t i o n s is

r e l a t e d t o t h e t a n δ o f t h e p o l y m e r i n t h e range temperatures

o f frequencies a n d

f o u n d i n the p a r t i c u l a r a p p l i c a t i o n . A m a j o r l i m i t a t i o n o f

c o n v e n t i o n a l a m o r p h o u s h o m o p o l y m e r s is that t h e r e g i o n o f h i g h t a n δ ( > 0.8) extends over o n l y 2 0 ° - 3 0 ° C , at 1 H z , i n the g l a s s - r u b b e r t r a n s i t i o n r e g i o n (4). T h e r e have b e e n m a n y attempts to b r o a d e n this d a m p i n g p e a k b y t h e a d d i t i o n of plasticizers a n d fillers, b u t w i t h o n l y l i m i t e d success (5,6).

H o w e v e r , t h e w i d t h o f the p e a k c a n b e r e a d i l y c o n t r o l l e d

i n p o l y m e r b l e n d s (7,8,9).

Recently, interpenetrating networks ( I P N )

h a v e b e e n p r e p a r e d that s h o w e x c e p t i o n a l l y b r o a d a n d h i g h t a n δ m a x i m a , Current address: Materials Research Laboratory, Polymer Science and Engineer ing, University of Massachusetts, Amherst, MA 01003. 1

0-8412-0457-8/79/33-176-153$06.50/0 © 1979 American Chemical Society

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

154

POLYMERS

MULTIPHASE

and they have properties in damping applications that are significantly better than other commercially available damping materials (5).

It is

thought that the broad maxima in tan Β observed in IPNs arises from a partial phase separation of the network chains such that regions of con tinuously varying composition are found rather than the regions of p i r e homopolymer normally observed in polymer blends. E a c h volume element with a given composition contributes to the overall properties, leading to a broad tan 8 peak. The tendency of an amorphous multicomponent polymer system to Downloaded by UNIV OF ARIZONA on October 2, 2015 | http://pubs.acs.org Publication Date: June 1, 1979 | doi: 10.1021/ba-1979-0176.ch008

phase separate is driven by the large negative enthalpy of the phaseseparated state relative to a homogeneous mixture (11), Scott-Hildebrand solution theory (10),

In terms of the

this negative enthalpy is related

to the difference in solubility parameter of the components and their molecular weight.

The tendency to phase separate is opposed by the

loss in entropy caused by the reduction in chain configurations on phase separation.

In principle, polymer blocks, grafts, blends, and IPNs could

all show partial phase separation with a suitable choice of polymers and chain topology. The remarkable properties of amorphous block polymers, particularly poly ( styrene-b-diene ), have been studied extensively in recent years. Many studies (JO, 35, 36, 37, 38) suggest that the degree of phase separa tion depends on the length of, the number of, and the chemical compo sition of the blocks. The aim of the present study was to prepare multiblock polymers having a suitable combination of these three variables so that the change between a polymer showing phase separation

to one behaving as a

homogeneous mixture could be observed in a thermoplastic.

In this

intermediate region, properties similar to those of IPNs might be expected. The properties of these materials also would be of interest in comparison with the semicrystalline multiblock polymers such as the

segmented

polyurethanes and poly ( ethcr-b-ester ) s that are available commercially. Approach A series of amorphous condensation multiblock polymers were pre pared comprising poly ( oxypropylene oxyterephthaloyl ) ( 3 I G T ) , a brittle glassy solid, as the hard block and poly ( oxypropylene ) ( P P O ) or poly( di ( oxyethylene ) oxyadipoy 1 ) ( P D E G A ) as the soft block. Polymer

Preparation

The polymerization method used was a polycondensation of terephthaloyl chloride, propane 1,2-diol, and the appropriate soft block ( Figure 1) in a 20% solution in dry 1,2-dichloroethane at 8 5 ° C for 48 hours.


8.

WATTS

A N D

HO-CH-CH-OH ι 2 CH

•O-CH-CH.; CH

ppo

3

155

Amorphous Poly(ether-b-ester)

WHITE

3

propane

1.2 diol

or - + O-CH^CH^O-CH^CH^O-p-fCH^CrO-} PDECA

0


soft block

CI

d

0

ferephrhaloyl chbride

hard block

sofr Hock MW - prepolymer MW = χ wr °fo prepolymer 25 [ 50 j 75

hard bbc* MW

~~ 2x | χ | / x

Figure 1.

2

Preparation of the multiblock polymers

T h e m o l a r r a t i o of soft b l o c k to p r o p a n e

1,2-diol a n d t e r e p h t h a l o y l

c h l o r i d e w a s A : B : ( A + Β ) X 1.01. F o u r moles of p y r i d i n e p e r m o l e of a c i d c h l o r i d e w a s a d d e d to react w i t h t h e H C L p r o d u c e d i n t h e p o l y merization.

P y r i d i n e h y d r o c h l o r i d e w a s r e m o v e d at t h e e n d of t h e

reaction b y w a s h i n g w i t h dilute H C L Multiblock polymers were prepared from P P O prepolymers

with

m o l e c u l a r w e i g h t s 400, 1000, 2000, 3000, a n d w e i g h t fractions of P P O 25, 50, a n d 7 5 % . P P O " h o m o p o l y m e r s " w e r e p r e p a r e d b y r e a c t i n g P P O p r e p o l y m e r w i t h t e r e p h t h a l o y l c h l o r i d e alone.

A s a m p l e also w a s p r e

p a r e d c o n t a i n i n g 5 0 % P D E G A of m o l w t 2550. T h e p o l y m e r s w e r e c h a r a c t e r i z e d b y v i s c o m e t r y a n d G P C analysis. T h e viscosities w e r e m e a s u r e d as 0.5 g d l " solutions i n 1,1,2,2-tetra1

chloroethane

at 2 5 ° C .

G e l permeation chromatograms

were

measured

i n d i m e t h y l a c e t a m i d e s o l u t i o n at 8 0 ° C . A t y p i c a l c h r o m a t o g r a m of 3 I G T h o m o p o l y m e r is g i v e n i n F i g u r e 2. T h e r e is a s m a l l s e c o n d a r y p e a k at h i g h e l u t i o n v o l u m e . T h i s s e c o n d a r y p e a k a p p e a r e d i n a l l of t h e p o l y m e r s p r e p a r e d f r o m t e r e p h t h a l o y l c h l o r i d e , a n d t h e e l u t i o n v o l u m e of t h e m a x i m u m w a s constant, i n d e p e n d e n t secondary

of the presence of P P O . T h i s

peak is t h o u g h t to b e a t t r i b u t a b l e

to r e s i d u a l

terephthalic

a c i d a n d c y c l i c d i m e r a n d t r i m e r that are f o r m e d i n the e a r l y stages of polycondensation

reactions

(15).

T h e simple construction

shown i n

F i g u r e 2 w a s u s e d to r e m o v e the l o w - m o l e c u l a r - w e i g h t peak, a n d t h e c h r o m a t o g r a m s w e r e c o n v e r t e d to p o l y ( s t y r e n e ) m o l e c u l a r w e i g h t u s i n g a c o m p u t e r p r o g r a m s u p p l i e d b y t h e D e p a r t m e n t of C h e m i s t r y , U n i v e r sity of M a n c h e s t e r . A l l results are g i v e n i n T a b l e I. T h e o v e r a l l m o l e c u l a r w e i g h t of these p o l y m e r s is estimated as 12,000-20,000 f r o m v i s c o s i t y


156

MULTIPHASE POLYMERS

T a b l e I.

Data

Soft Block

Polymer


PPO/3IGT

( approx wt frac)

Wf o

Wj

400

100 75 50 25

0.720 0.526 0.421 0.215

0.280 0.420 0.500 0.637

2.03 1.53 1.17

1000

100 75 50 25

0.869 0.678 0.469 0.226

0.131 0.266 0.415 0.584

1.65 1.22 1.08

2000

100 75 50 25

0.930 0.724 0.548 0.314

0.070 0.216 0.341 0.511

1.35 1.15 1.06

3000

100

0.951

0.049

75 50 25

0.680 0.486 0.255

0.242 0.380 0.544

1.18 1.08 1.03

100 50

0.944 0.55

0.059 0.329

1.11

0

0.718

(mol wt)

2550 3IGT/C β 6

PP

TR

s

Τ of 3IGT homopolymer with the same molecular weight as the hard block. Single-point viscosities 0.5 g · dl" in tetrachlorethane at 25°C. g

1

Elution volume

Detector response

Figure 2.

GFC chromatogram of 3IGT prepared using terephthaloyl chloride (3IGT/C)


8.

WATTS AND WHITE

157


for the Polymers Hard


g

Block HrT

T /°C g

a

Tetrachloroethane 0.5/dl g- » (M 1

n

GPC in DMA" X 10~3 MJMJ

Tç/K

(tan δ max)

2.04 2.96 7.39

536 728 1640

8 13 12

0.401 0.615 0.548 0.375

56 71 59 29

2.03 2.26 2.18 1.97

251 271 283 315

2.59 5.54 16.39

643 1260 3607

9 32 71

0.550 0.842 0.556 0.455

92 63 54

1.49 2.61 2.28

229 248 267 308

3.98 8.38 21.84

926 1820 4553

22 46 78

0.423 0.502 0.490 0.413

34 49 39

2.03 2.46 2.22

0.425 0.398 0.494 0.391

30 (14.30) 33 52 64

0.415 0.425

31 37

0.319

51

7.13 15.77 43.02

1566 3368 8852

10.25

2199

c d

41 68 90

a

1.83 (2.99) * 2.06 2.29 2.12 1.74 2.16

221 235 260 308 219 234

—.

317

241 261 363 (DSC)

G P C in dimethyl acetamide solution at 80°C, poly(styrene) calibration. G P C in dimethyl acetamide solution at 80°C, poly(oxyethylene) calibration.

a n d G P C d a t a (16,17). T h e ratio of M / M ^ i n terms of p o l y ( s t y r e n e ) m o l e c u l a r w e i g h t w a s 1.7/2.6; a s i m i l a r range has b e e n r e p o r t e d f o r p o l y ( oxytetramethylene oxyterephthaloyl-co-oxysebacoyl) random co polymers ( 2 2 ) . w

Naming

System

T h e m u l t i b l o c k p o l y m e r s are d i s t i n g u i s h e d b y soft-block t y p e , t h e m o l e c u l a r w e i g h t of t h e soft b l o c k , a n d the a p p r o p r i a t e w e i g h t f r a c t i o n of t h e soft b l o c k . T h e r e f o r e , P P O 3000/50 refers to a P P O / 3 I G T b l o c k p o l y m e r , p r e p a r e d f r o m a P P O p r e p o l y m e r w i t h m o l e c u l a r w e i g h t of 3000 a n d c o n t a i n i n g a p p r o x i m a t e l y 5 0 % b y w e i g h t of P P O . P P O 3000/ 100 represents a P P O " h o m o p o l y m e r " p r e p a r e d b y l i n k i n g a P P O p r e p o l y m e r m o l w t 3000 w i t h t e r e p h t h a l o y l c h l o r i d e . 3 I G T / C refers t o 3 I G T p r e p a r e d f r o m t e r e p h t h a l o y l c h l o r i d e a n d 3 I G T / M to m e l t - p o l y m e r i z e d 3 I G T u s i n g d i m e t h y l terephthalate.


158

MULTIPHASE POLYMERS

Block Molecular

Weights

T h e s e q u e n c e d i s t r i b u t i o n o f m o n o m e r residues i n c o p o l y c o n d e n s a t i o n reactions of this t y p e has b e e n s t u d i e d i n d e t a i l b y P e e b l e s

(18,39).

If a l l monomers are assumed to have e q u a l reactivity a n d i f the reaction has g o n e t o c o m p l e t i o n , t h e n u m b e r - a v e r a g e

sequence length

of 3 I G

r e s i d u e s ( g ) is g i v e n b y :


__ g=

1

[3IG] + [PPOIo rpprvi 0

, . ... , , . Jo = i n i t i a l c o n c e n t r a t i o n

r

+

[

Similarly, for P P O residues: S

[3IG]

0

+

[PPO]o

[3IG]

0

T h e s e q u e n c e lengths f o l l o w a "most p r o b a b l e " d i s t r i b u t i o n ; v a l u e s o f s~ a n d g f o r e a c h p o l y m e r a r e g i v e n i n T a b l e I . B e c a u s e o f t h e h i g h m o l e c u l a r w e i g h t o f P P O , ~s is g e n e r a l l y less t h a n t w o , so t h e m o l e c u l a r w e i g h t o f t h e soft b l o c k w i l l b e t a k e n as t h e m o l e c u l a r w e i g h t o f t h e PPO

prepolymer.

T h e molecular weight

of the h a r d block

(Hn) is

given b y :

# n = 2O6 0 + 148 206 = m o l w t of repeat u n i t 148 = m o l w t of o x y t e r e p h t h a l o y l residue T o a first a p p r o x i m a t i o n , a m u l t i b l o c k p o l y m e r p r e p a r e d f r o m P P O w i t h molecular weight χ containing 5 0 % P P O b y weight w i l l have a h a r d b l o c k m o l e c u l a r w e i g h t o f x; o n e c o n t a i n i n g 2 5 % w i l l h a v e a h a r d - b l o c k m o l e c u l a r w e i g h t o f 2x; a n d o n e c o n t a i n i n g 7 5 % P P O a h a r d - b l o c k of x/2 ( F i g u r e 1 ) . Melt Polymerization

of 3IGT

Low-molecular-weight 3 I G T homopolymers

(1000-8000) were pre

p a r e d b y m e l t p o l y c o n d e n s a t i o n (19) u s i n g d i m e t h y l t e r e p h t h a l a t e , a n d t h e T s w e r e m e a s u r e d u s i n g D S C . M o l e c u l a r w e i g h t s u p t o 4000 w e r e g

m e a s u r e d b y e n d - g r o u p analysis, h i g h e r m o l e c u l a r w e i g h t s w e r e e s t i m a t e d b y e x t r a p o l a t i o n o f t h e T / m o l w t curves (16,17). g

A n attempt w a s m a d e

to p r e p a r e P P O 3000/50 b y t h e same m e t h o d , b u t t h e P P O f o r m e d a separate l a y e r i n t h e m e l t b e f o r e h i g h - m o l e c u l a r - w e i g h t p o l y m e r w a s f o r m e d a n d the attempt was abandoned.


8.

WATTS AND WHITE

Mechanical

159


Testing

T h e r o o m - t e m p e r a t u r e p r o p e r t i e s of the p o l y m e r s v a r i e d f r o m v i s c o elastic l i q u i d s f o r 1 0 0 % P P O t h r o u g h soft ( 5 0 % P P O ) a n d t o u g h ( 2 5 % P P O ) solids to a b r i t t l e glass ( 3 I G T ) . u s e d as t h e d y n a m i c m e c h a n i c a l - t e s t

A torsional b r a i d p e n d u l u m was method, because only w i t h a sup

p o r t e d s a m p l e c o u l d of t h e p o l y m e r s b e t e s t e d o n o n e a p p a r a t u s , a n d o n l y s m a l l a m o u n t s of the p o l y m e r s w e r e a v a i l a b l e .

T h e torsional pen

d u l u m was based o n Gillham's design ( 2 0 ) , w i t h the inertia disc m o t i o n


being detected b y a Hall-effect device.

T h e glass substrate c o n s i s t e d of

t w o glass r o v i n g s t w i s t e d a r o u n d e a c h other b y " d o u b l i n g " to g i v e a u n i f o r m b u n d l e of 1680 filaments t h a t a c t e d as s u p p o r t f o r t h e p o l y m e r , w i t h t h e ends of t h e glass t r a p p e d i n c r i m p tags. T h e p o l y m e r w a s cast onto t h e b r a i d as a 3 0 % s o l u t i o n i n a s u i t a b l e solvent, a n d t h e s o l v e n t r e m o v e d s l o w l y at a t m o s p h e r i c pressure a n d u n d e r v a c u u m to l e a v e a c o m p o s i t e c o n s i s t i n g of a p o l y m e r m a t r i x a n d the glass s u p p o r t .

The

volume fraction of polymer i n the b r a i d ( φ ) was calculated f r o m the ρ

w e i g h t p e r u n i t l e n g t h of the b r a i d , k n o w i n g the a m o u n t of glass p r e s e n t a n d a s s u m i n g a p o l y m e r d e n s i t y of 1.0. T h e b r a i d s w e r e tested f r o m — 1 0 0 ° C u p w a r d s at a h e a t i n g rate of 1 ° C m i n " a n d a f r e q u e n c y of « 1

Χ

1 H z , u s i n g a n i n e r t i a l w e i g h t of 4.55

10" k g m . T h e d a m p e d sine w a v e s w e r e p r o c e s s e d b y h a n d t o g i v e 5

2

log decrement

a n d m o d u l u s . T h e r a d i u s of t h e s a m p l e w a s c a l c u l a t e d

f r o m the w e i g h t p e r u n i t l e n g t h , as above, w i t h t h e a d d i t i o n a l a s s u m p t i o n that the s a m p l e w a s a r i g h t c i r c u l a r c y l i n d e r a n d that t h e r e w e r e n o voids i n the sample.

The

Torsional Braid as a Composite

Material

I n a n y d i s c u s s i o n o f t h e results f r o m t o r s i o n a l b r a i d analysis i t is important

to establish

what

p r o p e r t i e s of t h e c o m p o s i t e .

c o n t r i b u t i o n t h e glass w i l l m a k e

to t h e

T h e p r i n c i p a l effects o f t h e glass a r e i l l u s

t r a t e d i n F i g u r e 3. T h e m o d u l u s a n d l o g - d e c r e m e n t curves f o r a s a m p l e of p o l y ( s t y r e n e )

a n d a b r a i d of p o l y ( s t y r e n e )

w e r e cast f r o m a t o l u e n e

s o l u t i o n a n d tested u s i n g t w o different i n e r t i a w e i g h t s . pure

poly(styrene)

pendulum

(21).

w a s tested o n a c o n v e n t i o n a l

a g r e e m e n t at l o w temperatures between

t h e curves.

that at h i g h temperatures constant

limiting

torsional

T h e m o d u l u s a n d d a m p i n g curves a r e i n f a i r l y close a n d i n t h e first p a r t o f t h e t r a n s i t i o n

region b u t b e y o n d the m a x i m u m i n l o g decrement, differences

T h e sample of

inverted

value.

there are

t h e m o d u l u s of t h e c o m p o s i t e Above

major

M o s t i m p o r t a n t is i n t h e o b s e r v a t i o n t h e glass-transition

tends

temperature,

to a the

m o d u l u s of t h e p o l y ( s t y r e n e ) m a t r i x b e c o m e s v e r y s m a l l , so this l i m i t i n g


160


MULTIPHASE POLYMERS

Figure 3 . A comparison between the mechanical properties of poly (styrène) and a poly(styrene) braid. (Φ) Compression-molded sample of PS. PS braid cast from toluene, φρ = 0.78. (Ο) Il—4.55 Χ J O " kg m' . (+) 12—8.8 X J O " kg m'K 5

2

6

modulus must correspond to the torsional rigidity of the glass trapped between the two crimp tags.

T h e damping of the braid also tends to a

low constant value at high temperatures for the same reason. T h e effect of the different inertia weights (II, 12) is probably a result of the change in tension i n the sample, altering the configuration of the glass.

As a

result of the change in the damping curves at high temperatures, the T

g

as defined by the maximum in log decrement has been shifted down in


8.

WATTS AND WHITE

161


t e m p e r a t u r e b y a b o u t 5 ° C . T h e i m p o r t a n t c o n c l u s i o n o f this d i s c u s s i o n is that b e l o w t h e m a x i m u m i n l o g d e c r e m e n t t h e results f r o m t h e b r a i d are c o m p a r a b l e w i t h a s a m p l e of p u r e p o l y m e r , b u t a b o v e t h e m a x i m u m the p r o p e r t i e s of t h e glass substrate d o m i n a t e t h e c o m p o s i t e b r a i d . T h e v a l u e of t h e m o d u l u s of t h e p o l y ( s t y r e n e ) b r a i d at l o w t e m p e r a t u r e is s m a l l e r t h a n t h e s a m p l e of p u r e p o l y ( s t y r e n e ) b e c a u s e t h e crosss e c t i o n of the b r a i d is r a t h e r i r r e g u l a r , a n d t h e a p p r o x i m a t i o n o f a n i r r e g u l a r cross-section b y a c i r c u l a r o n e w i l l i n e v i t a b l y l e a d t o a n u n d e r estimate of m o d u l u s (21).

F o r this reason, t h e a b s o l u t e v a l u e s o f t h e


m o d u l u s of t h e m u l t i b l o c k p o l y m e r s i n F i g u r e s 4 - 1 0 a r e u n r e l i a b l e . It s h o u l d b e n o t e d that a T

L i L

w o u l d n o t b e e x p e c t e d i n this p o l y -

( styrene ) b r a i d s a m p l e b e c a u s e of its h i g h 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 100,000 ) (46).

A l s o , this analysis of t h e c o m p o s i t e s t r u c t u r e of

the b r a i d s u p p o r t s N i e l s e n ' s (47)

s u g g e s t i o n that T , L arises s o l e l y f r o m L

the r e s i d u a l elasticity o f t h e glass. T

L f

T h e torsional p e n d u l u m , braid, a n d

L w i l l be discussed i n more detail elsewhere

Properties of the Multiblock

(16,17).

Polymers

F i g u r e 4 shows t h e p r o p e r t i e s of P P O 3000/50 cast f r o m m e t h y l e t h y l ketone two

( M E K ) a n d toluene.

T h e s a m p l e cast f r o m M E K shows

e q u a l - s i z e d peaks i n l o g d e c r e m e n t b u t i n t h e s a m p l e cast f r o m

t o l u e n e , t h e h i g h - t e m p e r a t u r e p e a k is m u c h l a r g e r t h a n t h e l o w - t e m p e r a ture peak.

T h e s e v a r i a t i o n s are t y p i c a l of a t w o - p h a s e c o m p o s i t e i n

w h i c h t h e m o r p h o l o g y is c o n t r o l l e d b y t h e c a s t i n g solvent (21).

A l l of

t h e o t h e r samples w e r e cast f r o m solutions i n M E K . T h e results f o r a l l o f the o t h e r samples a r e s u m m a r i z e d i n F i g u r e s 5, 6, 7, 8, a n d 9. T h e series of p o l y m e r s p r e p a r e d f r o m P P O m o l w t 400 a l l s h o w e d a s h a r p t r a n s i t i o n region similar to p o l y (styrene).

A s a m p l e of m e l t p o l y m e r i z e d 3 I G T of

m o l w t 2750 also is s h o w n . A s t h e b l o c k m o l e c u l a r w e i g h t increases, t h e t r a n s i t i o n r e g i o n b e c o m e s p r o g r e s s i v e l y b r o a d e r u n t i l i n P P O 3000/50 a d o u b l e p e a k is f o r m e d . samples

T h e b r e a d t h of t h e t r a n s i t i o n r e g i o n i n t h e

p r e p a r e d f r o m h i g h - m o l e c u l a r - w e i g h t P P O m a y b e t a k e n as

e v i d e n c e of some f o r m of phase s e p a r a t i o n . Small Angle

X-Ray

Results

S m a l l angle x - r a y p i c t u r e s of m e l t - p r e s s e d films of P P O 3000/50 a n d 3000/25 cast f r o m M E K s h o w e d a w e l l - d e f i n e d d i f f r a c t i o n r i n g g i v i n g a m e a s u r e of the size of t h e i n h o m o g e n e i t i e s i n t h e m a t e r i a l . A M E K - c a s t film

of P P O 3000/50 gave i d e n t i c a l results.

A s a m p l e o f P P O 2000/25

g a v e a diffuse s c a t t e r i n g after t h r e e times t h e e x p o s u r e

of t h e P P O

3000/50, i n d i c a t i n g t h e p r e s e n c e of i r r e g u l a r i n h o m o g e n e i t i e s w i t h less difference i n e l e c t r o n d e n s i t y b e t w e e n t h e s c a t t e r i n g regions ( F i g u r e 1 0 ) .



Figure 4.

-80

-60

0

·

-40

·

-20 0 T/°C

···»··

20

• °

0

40

0

60

%

The effect of casting solvent on the properties of PPO 3000/50. (O) Cast from MEK, φρ 0.87. (Φ) Cast from toluene, φρ = 0.66.

005

0-1

0-5

50


m

o r

S

to



*g SXIHAV ONV SXXVAV (*d}Sd-q'i9iii9)fi\o^ snoi[dxoiuy


Figure 6. The properties of polymers prepared from PPO of mol wt 1000. (χ) PPO 1000/100, φρ — 0.79. (+) PPO 1000/75, φρ = 0.86. (Φ) PPO 1000/50, φρ = 0.85. (Ο) PPO 1000/25, φρ = 0.79.


W

Ο

W

β


Figure 7. The properties of polymers prepared from PPO of mol wt 2000. (χ) PPO 2000/100, φρ — 0.65. (+) PPO 2000/75, φρ = 0.81. (Φ) PPO 2000/50, φρ = 0.82. (Ο) PPO 2000/25, φρ = 0.85.



Figwre 8. T/ie properties of polymers prepared from PPO of mol wt 3000. (x) PPO 3000/100, φρ = 0.68. (+) PPO 3000/75, φρ ΝΑ. (Φ) PPO 3000/50, φρ = 0.87. (Ο) PPO 3000/25, φρ = 0.79.


CO

»

Νί

r

hi Ο

Μ

Μ

σ>


Figure 9.

The properties of polymers prepared from PDEGA of mol wt 2550. (X) PDEGA φρ = 0.74. (*) PDEGA 2550/50, φρ = 0.79.


2550/100

-4

h-* Φ

& CL

cr

sa *î*

«"•«

Ο

r

•a

ο

M

>

CO

>

00

168


MULTIPHASE POLYMERS

Figure 10. Small angle x-ray pictures of the multiblock polymers, (top) PPO 3000/25, 24-hr exposure, (middle) PPO 3000/50, 24-hr exposure, (bottom) PPO 2000/25, 50-hr exposure.


8.

WATTS AND WHITE

169


Discussion The small angle x-ray results show that regular inhomogeneities were present in samples P P O 3000/50 and 3000/25.

T h e crucial question i n

any study of this type is what sort of phase separation has occurred in these polymers? T h e blocks, whole chains with slightly different compo sition, or low-molecular-weight impurities could have separated out. It is well established that the size of the inhomogeneities produced by phase separation of the blocks i n a block copolymer are controlled b y the


molecular weight of the blocks (24, 25) because the joints between the blocks must lie in the interfacial region between the domains ( Figure 11).

Β

Α

Β

A

Interfacial volume fraction

Β

f= D *0B-2X A

Figure 11.

Diagram of phase separation of a multiblock polymer

Table II shows the Bragg spacing and the sum of the unperturbed block dimensions for P P O 3000/50 and 3000/25, < r > was estimated 0

from the values for P P O , and poly ( oxyethylene oxyterephthaloyl ) given in the literature (26).

As the average block molecular weight increased,

the Bragg spacing also increased and is the same order of magnitude as the unperturbed block dimensions. This can be taken as a clear indication that phase separation of the blocks has occurred i n P P O 3000/50 and 3000/25.


170

MULTIPHASE POLYMERS

Table II. Small Angle Scattering Data

Polymer

PPO (mol wt)

SIGT ( mol wt)

Average (mol wt)

P P O 3000/50 P P O 3000/25

3000 3000

3368 8852

3184 5926

° R = po


0

P

3iG ;

+

Τg/Composition

T

Mi

~

Bragg Spacing

R° 10.09 n m 13.3 n m

14.4 n m 19.2 n m

0.087 nm.

Relation

If t h e p o l y m e r s d o n o t s h o w p h a s e s e p a r a t i o n they c a n b e c o n s i d e r e d as r a n d o m c o p o l y m e r s .

The T

g

of a r a n d o m c o p o l y m e r solely

depends

o n c o m p o s i t i o n i f t h e m o l e c u l a r w e i g h t is sufficiently h i g h f o r T

g

to b e

i n d e p e n d e n t of m o l e c u l a r w e i g h t ( 2 7 ) . I t has b e e n e s t a b l i s h e d that t h e m o l e c u l a r w e i g h t o f 3 I G T / C is h i g h e n o u g h t o m a k e t h e T

g

of m o l e c u l a r w e i g h t (16,17). monomers appear.

independent

I n these c o p o l y m e r s t h e residues of t h r e e

T o define t h e c o m p o s i t i o n of a l l o f t h e P P O - b a s e d

c o p o l y m e r s b y o n e w e i g h t f r a c t i o n , t h e c o n t r i b u t i o n s o f t h e other t w o c o m p o n e n t s m u s t b e a d d e d together.

-^0-ΟΗ -(ρ-]-

-[Lo-CH -CH-J-

2

C H

3

2

CH

n

P P O residue

^0-c7oVc4 ο

8

propane-1,2-diol

Ο

oxyterephthaloyl

residue

residue

D e f i n i n g T b y t h e m a x i m u m i n t a n δ, a p l o t o f T v s . w e i g h t - f r a c t i o n g

PPO dues

g

residues ( W f (Wf

T R

)

P P 0

)

and T

g

vs. weight-fraction oxyterephthaloyl resi

c a n b e c o m p a r e d i n F i g u r e 12. T h e p l o t against

Wf

T R

s h o w s t h e m a j o r i t y of t h e p o i n t s l y i n g o n a c u r v e ; those l y i n g off t h e c u r v e a r e i n d e x e d a n d c o r r e s p o n d to those p o l y m e r s w i t h u n s y m m e t r i c a l m a x i m a i n l o g decrement.

T h e points l y i n g o n t h e l i n e are those w i t h

single, s h a r p m a x i m a i n l o g d e c r e m e n t have

symmetrically

broadened

peaks

a n d the 5 0 % copolymers i n l o g decrement.

that

T h e simple

Tg-composition relationship f o r polymers w i t h a single sharp m a x i m a i n log

decrement

is e v i d e n c e

random copolymers.

that t h e y

are behaving

like

homogeneous

S i m i l a r l y , those p o l y m e r s that d o n o t l i e o n t h e l i n e

m u s t b e p h a s e s e p a r a t e d b e c a u s e t h e regions p r o d u c i n g t h e m a x i m a i n l o g d e c r e m e n t h a v e a different c o m p o s i t i o n t o t h e o r i g i n a l p o l y m e r . T h e


WATTS AND WHITE



• • 2 1

3

00

02

_J

0-4

l_

Wf

06

08

10

r p o

Figure 12. T against copolymer composition defined by weight fraction oxyterephthaloyl and PPO residues. (1) PPO 3000/25, (2) PPO 2000/25, (3) PPO 1000/25, (4) g

PPO 2000/75, (5) PPO 3000/75.


172 T

G

MULTIPHASE

POLYMERS

of p o l y ( 1 , 4 p h e n y l e n e t e r e p h t h a l o y l ) has b e e n r e p o r t e d as 540 Κ

A l l of the points c o u l d not b e

fitted

b y the general

(41).

Τ J composition

f o r m u l a b y W o o d ( 2 7 ) , even w h e n t h e T o f p o l y ( o x y t e r e p h t h a l o y l ) w a s G

a l l o w e d to float. I f t h e p o i n t f o r 3 I G T w a s o m i t t e d , t h e rest of t h e p o i n t s w e r e fitted b y t h e F o x e q u a t i o n ( 40 ), s h o w n as a d a s h e d l i n e i n F i g u r e 12.

1

W ' rp

rp


1

The T

g

S

1

t

gl

i*

Wg rp 1

g2

against w e i g h t - f r a c t i o n P P O - r e s i d u e s g r a p h shows a general

T / c o m p o s i t i o n curve w i t h significantly more g

scatter t h a n t h e W f

T R

p l o t ( F i g u r e 1 2 ) . I n d e f i n i n g the c o p o l y m e r b y W f p , t h e T is a s s u m e d P 0

G

i n d e p e n d e n t o f v a r i a t i o n s i n t h e ratio of t e r e p h t h a l o y l - t o - d i o l I n t h e case o f W f

T R

, the T

G

residues.

is a s s u m e d i n d e p e n d e n t of variations i n t h e

r a t i o of P P O to d i o l b y w e i g h t . B e c a u s e P P O a n d p r o p a n e 1,2-diol h a v e the same r e p e a t i n g u n i t , t h e i r c o n t r i b u t i o n to c h a i n same a n d h e n c e W f

flexibility

w i l l be the

p r o v i d e s t h e best m e a s u r e o f t h e c o m p o s i t i o n o f

T R

the p o l y m e r s .

Analysis The

of the Mechanical

Properties

morphology a n d composition variation found i n the

phase-

separated materials c a n b e d e d u c e d f r o m t h e s h a p e a n d p o s i t i o n o f t h e d a m p i n g curves.

Two-phase

composites

are g e n e r a l l y

f o u n d i n three

b a s i c m o r p h o l o g i e s ; p h a s e 1 d i s p e r s e d i n a m a t r i x of p h a s e 2, p h a s e 2 d i s p e r s e d i n a m a t r i x of phase 1, a n d a l a m e l l a m o r p h o l o g y i n w h i c h b o t h phases are c o n t i n u o u s .

If p h a s e 1 is a r u b b e r a n d phase 2 a glass,

t h e n t h e m o d u l u s of t h e c o m p o s i t e d e p e n d s c r u c i a l l y o n t h e m o r p h o l o g y . If o n e o f t h e phases is d i s p e r s e d , t h e c o n t i n u o u s phase dominates t h e d i s p e r s e d phase, l e a d i n g to a n impact-resistant a n d a filled r u b b e r i n t h e second.

glass i n t h e first case

I n the case of a l a m e l l a m o r p h o l o g y ,

b o t h phases c o n t r i b u t e e q u a l l y to t h e m o d u l u s of t h e c o m p o s i t e l o g a r i t h m i c l a w of m i x i n g .

in a

C o n s e q u e n t l y , t h e size of t h e t a n δ peaks

c o r r e s p o n d i n g to t h e T of t h e phases also w i l l d e p e n d o n t h e m o r p h o l o g y . G

The

tan δ peak

for the continuous

phase is larger t h a n that of t h e

d i s p e r s e d phase, a n d a l a m e l l a m o r p h o l o g y w i l l l e a d t o t w o e q u a l l y s i z e d peaks.

T h i s m a y b e seen i n t h e e x p e r i m e n t a l d a t a o n p o l y ( s t y r e n e - b -

d i e n e ) p o l y m e r s (28,45) a n d f o l l o w s f r o m t h e r e l a t i o n s h i p b e t w e e n t a n δ a n d t h e d i f f e r e n t i a l of t h e l o g of t h e r e a l m o d u l u s . T h e r e l a t i o n s h i p b e t w e e n t a n δ a n d the viscoelastic f u n c t i o n s is d i s c u s s e d i n R e f s . 6, 16, 21, Ref.

a n d 44, a n d t h e properties

of composites

have been

reviewed i n

21.


8.

WATTS AND WHITE

173


T h e f o l l o w i n g assumptions are made i n a n a l y z i n g t h e m e c h a n i c a l p r o p e r t y results. I n a c o m p l e t e l y p h a s e - s e p a r a t e d system, t h e T

g

soft b l o c k is t h e same as t h e T

of the

o f t h e P P O " h o m o p o l y m e r s , " e.g., P P O

g

3000/100. T h e T o f t h e h a r d b l o c k o f a g i v e n m o l e c u l a r w e i g h t is t h e g

same as t h e T

g

of t h e free h o m o p o l y m e r w i t h same m o l e c u l a r w e i g h t .

T h e overall glass-rubber

t r a n s i t i o n is c o n s i d e r e d t o arise f r o m i n c r e -

m e n t a l c o n t r i b u t i o n s o f regions o f different c o m p o s i t i o n c o m b i n e d t o gether as i n a c o n v e n t i o n a l c o m p o s i t e .


PPO

400/75/50/25,

1000/75

(Figures

5 and 6)

T h e s e a l l s h o w a single s h a r p m a x i m a i n l o g d e c r e m e n t

and a

s i m p l e r e l a t i o n s h i p b e t w e e n T a n d c o m p o s i t i o n , i n d i c a t i n g that t h e y a r e g

homogeneous materials. PPO

1000/50,

2000/50

(Figures

6 and 7)

B o t h samples s h o w a s y m m e t r i c a l l y b r o a d e n e d p e a k i n l o g d e c r e m e n t . T h e w i d t h o f t h e p e a k i n P P O 2000/50 i n d i c a t e s that regions w i t h w i d e l y v a r y i n g c o m p o s i t i o n a r e present a n d t h e n a r r o w e r p e a k i n P P O 1000/50 i n d i c a t e s that less p h a s e s e p a r a t i o n has o c c u r r e d i n this s a m p l e . T h e f a c t that t h e m a x i m a o f t h e l o g - d e c r e m e n t peaks l i e o n t h e T / g

c o m p o s i t i o n c u r v e a n d these peaks a r e s y m m e t r i c a l l y b r o a d e n e d i n d i c a t e s that regions w i t h t h e same c o m p o s i t i o n as t h e o r i g i n a l p o l y m e r are m o s t c o m m o n a n d the regions of v a r y i n g c o m p o s i t i o n s a r e a r r a n g e d i n a l a m e l l a m o r p h o l o g y i n w h i c h t h e y a l l c o n t r i b u t e e q u a l l y to t h e o v e r a l l p r o p e r t i e s of t h e c o m p o s i t e . PPO

3000/50 The

(Figures

presence

4 and 8)

o f t w o peaks

i n l o g decrement

shows

that

phase

s e p a r a t i o n has d e v e l o p e d sufficiently f o r regions r i c h i n P P O a n d 3 I G T to b e most c o m m o n . T h e differences b e t w e e n t h e temperatures o f these t w o m a x i m a a n d t h e T s o f t h e b l o c k s i f c o m p l e t e phase s e p a r a t i o n h a d g

o c c u r r e d are s h o w n i n T a b l e I I I . T h e t w o peaks i n t h e M E K - c a s t s a m p l e are i n d i c a t i v e o f a l a m e l l a - l i k e m o r p h o l o g y . T h e difference i n t h e size of t h e peaks i n t h e toluene-cast

sample indicates a 3 I G T matrix con-

t a i n i n g P P O - r i c h d i s p e r s e d regions. T h i s d e p e n d e n c e o f b l o c k p o l y m e r p r o p e r t y o n c a s t i n g solvent also is seen i n p o l y ( s t y r e n e - b - d i e n e ) p o l y m e r s ( 2 8 ) . T h e o r e t i c a l w o r k ( 2 3 ) has s h o w n that t h e t h e r m o d y n a m i c a l l y m o s t stable m o r p h o l o g y f o r a d i b l o c k p o l y m e r c o n t a i n i n g 5 0 % o f e a c h c o m p o n e n t is a l a m e l l a m o r phology.

F o r this reason M E K w a s c h o s e n f o r t h e tests o n a l l o t h e r

polymers.


MULTIPHASE POLYMERS

174

Table III.

Values of the Phase-Separated

T

g

Regions

Maxima in Log. Dec. High Temp (°C)

Sample


P P O 3000/50: M E K C a s t P P O 3000/50: T o l u e n e C a s t P P O 3000/100 3 I G T / M m o l w t 3368

P P O 3000/25

(Figure

Low Temp (°C) -35 -40 -54

5 35 68

8)

P P O 3000/25 p r o d u c e s a s m a l l a n g l e x-ray d i f f r a c t i o n r i n g b u t o n l y a single m a x i m a i n l o g decrement w i t h a long, low-temperature tail. T h e c o m p o s i t i o n o f t h e regions p r o d u c i n g t h e m a x i m u m i n l o g d e c r e m e n t a r e different f r o m t h e c o m p o s i t i o n o f t h e p a r e n t p o l y m e r . T h e f a c t that a s e c o n d peak i n l o g d e c r e m e n t is n o t o b s e r v e d f o r t h e P P O - r i c h would

suggest that

t h e r e is a 3 I G T - r i c h m a t r i x t h a t

regions

dominates the

m e c h a n i c a l p r o p e r t i e s , w i t h P P O - r i c h d i s p e r s e d regions p r o d u c i n g t h e long, low-temperature component temperature

generally

tail. form

Block copolymers containing 2 5 % of one d i s p e r s e d phases

(23,29);

also,

the l o w -

t r a n s i t i o n i n P P O 3000/50 cast f r o m t o l u e n e is o n l y just

v i s i b l e , so i t is r e a s o n a b l e

that the reduction i n P P O w e i g h t fraction

w o u l d l e a d t o t h e d i s a p p e a r a n c e o f this t r a n s i t i o n .

P P O 2000/25,

1000/25

(Figures

6 and 7)

F r o m t h e same e v i d e n c e as a b o v e i t m a y b e d e d u c e d that t h e r e is a c o n t i n u o u s 3 I G T m a t r i x w i t h d i s p e r s e d P P O - r i c h r egions . T h e n a r r o w i n g o f t h e t a n δ m a x i m a i n d i c a t e s that t h e differences

i n composition

get p r o g r e s s i v e l y s m a l l e r w i t h l o w e r P P O m o l e c u l a r w e i g h t , i n l i n e w i t h the s m a l l a n g l e x-ray results.

PPO

3000/75,

2000/75

(Figures

7 and 8)

T h e s h i f t i n g o f t h e m a x i m a i n l o g d e c r e m e n t to l o w temperatures is the e v i d e n c e f o r p h a s e s e p a r a t i o n . T h e s e p o l y m e r s p r o b a b l y s h o w a l o n g l o w - t e m p e r a t u r e t a i l that has b e e n o b s c u r e d b y t h e l i m i t i n g m o d u l u s of the b r a i d .


8.

WATTS AND WHITE

PDEGA

2550/50

175


(Figure

9)

T h i s s a m p l e s h o w s a s l i g h t l y b r o a d e n e d p e a k s i m i l a r t o P P O 1000/50. A s described i n the introduction, the d r i v i n g force f o r phase separation comes f r o m t h e l a r g e n e g a t i v e relative

to the homogeneous

enthalpy of the phase-separated mixture.

T h e enthalpy

state

( Δ Η ) can be

q u a n t i f i e d i n terms o f t h e S c o t t - H i l d e b r a n d t h e o r y f o r these m u l t i b l o c k s


(10,12,16);

where

M is t h e average

block molecular weight.

T h e difference i n

s o l u b i l i t y parameters f o r t h e t w o c o p o l y m e r s c a n b e c a l c u l a t e d f r o m t h e table of group contributions ( 2 6 ) . PPO/3IGT

δχ —

PDEGA/3IGT

8 - 8 2 — 1.4

C l e a r l y t h e difference

§ 2=

= s

2.5

1

i n s o l u b i l i t y parameters

is consistent

with the

difference i n b l o c k m o l e c u l a r w e i g h t r e q u i r e d to p r o d u c e p h a s e

separa

t i o n i n these t w o c o p o l y m e r s . PPO

"Homopolymers"

and 3IGT

T h e s e p o l y m e r s represent t h e h o m o l o g o u s series s h o w n i n T a b l e IV. T h e s t r o n g s e c o n d a r y r e l a x a t i o n i n 3 I G T a n d P P O 400/100 is o b s e r v e d as a s h o u l d e r i n P P O 1000/100, 2000/100, a n d 3000/100. T h e s e c o n d a r y i n t e r e p h t h a l a t e p o l y m e r s is t h o u g h t t o arise f r o m t o r s i o n a l o s c i l l a t i o n s o f the

terephthalate

o b s e r v a t i o n that

units

(30,31); this m e c h a n i s m

t h e r e l a x a t i o n gets w e a k e r

is i n l i n e w i t h t h e

for the higher-molecular-

weight P P O polymers. Table I V .

Structure of the P P O "Homopolymers

Polymer

M

3IGT P P O 400/100 P P O 1000/100 P P O 2000/100 P P O 3000/100

1 6.8 17.3 34.5 51.7

1

0.718 0.28 0.131 0.07 0.049


176

MULTIPHASE POLYMERS

Sources

of

Uncertainty

T h e m a j o r source of u n c e r t a i n t y i n these results comes

from the

i n f l u e n c e t h e glass substrate m i g h t h a v e o n phase s e p a r a t i o n ; p r e f e r e n t i a l a b s o r p t i o n o f o n e of the b l o c k s onto the surface o f the glass (32) w o u l d obviously

affect

phase

separation.

T h e low-molecular-weight

o b s e r v e d i n t h e G P C curves also c o u l d affect t h e results.

peak

I n so f a r as

t h e T / c o m p o s i t i o n c u r v e ( F i g u r e 12) shows a d i r e c t T / c o m p o s i t i o n g

g

relation w i t h symmetrical displacement of the 2 5 % a n d 7 5 % copoly


mers a b o v e a n d b e l o w t h e l i n e , there is n o e v i d e n c e to suggest these other factors a r e a f f e c t i n g phase separation.

that

T h e d e t a i l e d analysis

of t o r s i o n a l p e n d u l u m d a t a is also r a t h e r u n c e r t a i n at h i g h d a m p i n g v a l u e s ( 3 3 ) , as is the analysis o f m u l t i p h a s e systems b y s i n g l e - f r e q u e n c y i s o c h r o n a l d a t a (34). m u m i n log decrement

F o r most of t h e curves d i s c u s s e d here, t h e m a x i is a b o u t 1.0, a n d these effects a r e l i k e l y t o b e

" s e c o n d o r d e r " c o m p a r e d w i t h t h e effect o f t h e b r a i d a n d t h e l a r g e differences o b s e r v e d b e t w e e n the samples. Conclusions T h e s e q u e n c e o f curves i n F i g u r e s 5 - 1 1 shows t h e stages o f p a r t i a l p h a s e s e p a r a t i o n that o c c u r i n a n a m o r p h o u s m u l t i b l o c k p o l y m e r w i t h p o l y d i s p e r s e h a r d b l o c k s . B y s y s t e m a t i c a l l y v a r y i n g the b l o c k m o l e c u l a r weights

a n d copolymer composition, the breadth

a n d shape

of t h e

d a m p i n g peaks c h a n g e d i n a systematic a n d p r e d i c t a b l e w a y . C o n t r o l l e d p a r t i a l phase s e p a r a t i o n w o u l d a p p e a r t o b e a p o w e r f u l w a y t o t a i l o r i n g polymer properties for a particular application. T h e difference b e t w e e n these p o l y m e r s a n d c o n v e n t i o n a l H y t r e l - t y p e p o l y ( ether-b-esters ) is e m p h a s i z e d b y t h e a t t e m p t to p o l y m e r i z e P P O 3000/50 b y m e l t p o l y c o n d e n s a t i o n , the m e t h o d n o r m a l l y u s e d f o r H y t r e l (42).

C o m p l e t e p h a s e s e p a r a t i o n o c c u r r e d , s h o w i n g that

the incom

p a t i b i l i t y b e t w e e n P P O / 3 I G T is m u c h greater t h a n p o l y ( o x y t e t r a m e t h y l ene-b-oxytetramethylene oxyterephthaloyl). Acknowledgment O n e of us ( M . P . C . W . ) w o u l d like to thank t h e Science

Research

C o u n c i l f o r financial s u p p o r t . Literature

Cited

1. Ungar, Ε . E., Hatch, D . K., Prod. Eng. (1961) 32, 41. 2. Ball, G . L., Salyer, I. O., J. Acoust. Soc. Am. (1966) 39, 663. 3. Sperling, L . H . , Thomas, D . Α., National Technical Information Service Tech. Bull. (1975) AD/A-003 852.



8.

WATTS AND WHITE


177

4. Hiejboeur, J., "Physics of Non-crystalline Solids," p. 231, J. A . Prins, E d . , North Holland, Netherlands, 1965. 5. Manson, J. Α., Sperling, L . H., "Polymer Blends and Composites," Plenum, New York, 1976. 6. McCrum, N . G . , Read, Β. E . , Williams, M . L . , "Anelastic and Dielectric Effects in Polymeric Solids," Wiley, New York, 1967. 7. Kollinsky, F., Markert, G . , "Multicomponent Polymer Systems," N . A . Platzer, E d . , ADV. C H E M . SER. (1971) 99, 175. 8. Kraus, G . , Rollman, K. W . , "Multicomponent Polymer Systems," N . A . Platzer, E d . , ADV. C H E M . SER. (1971) 99, 189. 9. Mitzumachi, J., Adhesion (1970) 2, 292. 10. Meier, D . J., Polym. Prepr. (1974) 15, 171. 11. Helfand, E., J. Chem. Phys. (1975) 62, 99. 12. Krause, S., Macromolecules (1970) 3, 84. 13. Leary, D . F., Williams, M . C., J. Polym. Sci., Polym. Phys. Ed. (1974) 12, 265. 14. Allport, D . C., James, W . H., "Block Copolymers," p. 208, Applied Science, United Kingdom, Division of Elsevier, New York, 1973. 15. Flory, P. J., "Principles of Polymer Chemistry," Cornell University, Ithaca, NY, 1953. 16. Watts, M . P. C., Ph.D. Thesis, University of Manchester, Institute of Sci ence and Technology, 1977. 17. Watts, M . P. C., White, E . F. T . , unpublished data. 18. Peebles, L . H., Macromolecules (1974) 9, 58. 19. Goodman, I., Rhys, J. H., "Polyesters," Vol. 1, IUife Books, London, 1965. 20. Gillham, J. K., A.I.Ch.E. J. (1974) 20.6, 1066. 21. Neilsen, L . E . , "Mechanical Properties of Polymers and Composites," Vol. I, Dekker, 1974. 22. Marrs, W., Still, R. H., Peters, R. H., J. Appl. Polym. Sci., in press. 23. Meier, D . J., "Block and Graft Copolymers," J. J. Burke, V . Weiss, Eds., Syracuse University, Syracuse, NY, 1973. 24. Kromer, H., Hoffmann, M . , Kampf, G . , Ber Bunsenges. Phys. Chem. (1970) 74, 859. 25. Helfand, E., Wasserman, Z. R., Polym. Eng. Sci. (1977) 17, 73. 26. "Polymer Handbook," 2nd ed., J. Brandrup, Ε . H. Immergut, Eds., Wiley -Interscience, 1975. 27. Wood, L . Α., J. Polym. Sci. (1958) 28, 319. 28. Miyamoto, S., Kodama, K., Shibayama, K., J. Polym. Sci., Polym. Phys. Ed. (1970) 8, 2095. 29. Folkes, M . J., Keller, Α., "Physics of Glassy Polymers," R. N . Howard, E d . , p. 548, Applied Science, 1973. 30. Yip, H. K., Williams, H. L . ,J.Appl.Polym. Sci. (1976) 20, 1217. 31. Sacher, E., J. Polym. Sci., Polym. Phys. Ed. (1968) 6, 1935. 32. Lipatov, Y. S., Adv. Polym. Sci. (1977) 22, 1. 33. Struick, L. C . E . , Rheol. Acta. (1967) 6, 119. 34. Tschoegl, N . W., Cohen, R. E . , 175th National ACS Meeting, California, 1978. 35. Toporowski, G . M . , Roovers, J. E . L . , J. Polym. Sci., Polym. Chem. Ed. (1976) 14, 2233. 36. Kraus, G . , Rollman, K. W . , J. Polym. Sci., Polym. Phys. Ed. (1976) 14, 1133. 37. Senich, G . Α., Macknight, W . J., ADV. C H E M . SER. (1979) 176, 97. 38. Matzner, M . , Noshay, Α., Robeson, L . M . , Merriam, N . , Barclay, R. Mc Grath, J. E., App. Polym. Symp. (1973) 22, 143. 39. Peebles, L . H., Macromolecules (1974) 7, 872. 40. Fox, T . G . , Bull. Am. Phys. Soc. (1956) 1, 123.


178

MULTIPHASE POLYMERS

41. Frosina, V . , Levita, G . , Landis, J., Woodward, A. E . , J. Polym. Sci. (1977) 15, 239. 42. Cella, R. J., J. Polym. Sci., Part C (1973) 42, 727. 43. Sperling, L . H., "Recent Advances in Polymer Blocks, Blends and Grafts," p. 152, Plenum, New York, 1974. 44. Schwartzl, F. R., Struick, L . C . E . , Adv. Mol. Relaxation Processes (1967) 1, 210. 45. Robinson, R. Α., White, E . F. T . , "Block Copolymers," S. L . Aggarwal, E d . , p. 123, Plenum, New York, 1970. 46. Stadniki, S. J., Gillham, J. K., Boyer, R. F., J. Appl. Polym. Sci. (1976) 20, 1245.


47. Neilsen, L . E., Polym. Eng. Sci. (1977) 17, 713. RECEIVED April 14, 1978.


Multiphase Polymers - American Chemical Society

Recommend Documents