Grafted-Block Copolymer Networks Formed by Transition Metal

Chapter 14

Grafted-Block Copolymer Networks Formed by Transition Metal Coordination of Styrene- and Butadiene-Based Polymers 1,4

1,2

1,3

A. Sen , R. A. Weiss , and A. Garton 1

Polymer Science Program, University of Connecticut, Storrs, CT 06269-3136 Department of Chemical Engineering, University of Connecticut, Storrs, CT 06269-3136 Department of Chemistry, University of Connecticut, Storrs, CT 06269-3136

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 9, 2015 | http://pubs.acs.org Publication Date: July 21, 1989 | doi: 10.1021/bk-1989-0395.ch014

2

3

Blends of functionalized polystyrene and polybutadien were prepared using transition metal coordination as a means of improving the interaction between the two polymers. The polystyrene contained 4.2 mole percent of 4-vinyl pyridine comonomer and the polybutadiene chains were terminated at both ends with copper carboxylate groups. Fourier transform infrared spectroscopy, electron spin resonance spectroscopy and small angle x-ray scattering evidence are presented for the formation of molecular interactions between the Cu-carboxylate and the vinyl pyridine groups. Although the blends were phase separated, improvements in miscibility were realized when the complex was formed. A molecular architecture similar to that of a physically crosslinked grafted-block copolymer is proposed. Thermal mechanical and dynamic mechanical analyses demonstrated a significant improvement in the mechanical properties of the blends compared with a blend in which only an acid-base type interaction was possible. The formation of the transition metal complex increased the rubbery modulus between the two glass transitions and gave rise to a new plateau region in the r modulus above the glass transition ofa c a d e m i c Polymer blende have eceived considerable i n d u s t r i a l and a t t e n t i othe n ipolystyrene-rich n recent y e a r s . phase. Ideally, two o r more p o l y m e r s may be blended

to

potentially often

not possible

unfavorable

l

form

a

wide

variety

d e s i r a b l e combinations t o achieve

thermodynamics

of

morphologies

of properties.

useful

o f mixing

compositions o f polymers.

that

However, because

offer i t i s of

The entropy

the of

Current address: Texaco, Inc., Beacon Research Laboratories, P.O. Box 509, Beacon, N Y 12508 0097-6156/89/0395-0353$06.00A) ο 1989 American Chemical Society

In Multiphase Polymers: Blends and Ionomers; Utracki, L., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1989.

354

MULTIPHASE POLYMERS: BLENDS AND IONOMERS

mixing

of polymers

mixing

i s dominated

positive Mixing such or

as

on

the

and

observed

that

dipole-dipole Eisenberg polymer

and

vinyl ionic

used

(telechelic) tertiary

Agnew stability. a

Peiffer zinc

pyridine)

to

literature Horrian In

improve

et

of

miscibility research, phases metal the

would

the was

two

result. was

and

Horrian

groups.

end-functionalized

exhibited

EPDM a n d

were

evaluated

the blends.

polymer. an

blends

carboxyl-terminated

polybutadiene

(CTB-Cu) w i t h p o l y ( s t y r e n e - c o - 4 - v i n y l

study

by

a

randomly

Although

complete

objective

of

though

judged

chapter and

the

transition

the graft,

(CTB)

this

between

and

as

this

the

"grafted-block"

adhesion

successful

In particular,

In

improve

functional!zed.

between

f o r promoting

more

complexation

of the

acid-base interactions

considerably

with

thermal

were t o

to prepare

not

high

of the blend.

interaction

improved

copolymer".

metal

the exception

was

and

formation

poly(styrene-co-vinyl

used were randomly was

acid

metal complexes

transition

that

of

of

acid

"multiblock

generally

polymers

properties salt

i n a

several between

between

a telechelic

Both

i n

Ion-pair

the goal

anticipated

coordination

latter

sulfonic

bonding, Similarly,

containing

the

of

interaction

f a r , the authors' intentions

herein

polymer

of

i t

and

With

to

enhance

blends

miscibility

acid-base

sulfonated

through

to

hydrogen

respectively.

these

of

blends

however,

groups

polybutadiene

(6) t h e p o l y m e r s

networks

functionalized

achieved an

a l . (8) u s e d

so

the use

o f polymer

studied

by

the mechanical properties

t h e work d e s c r i b e d

copolymer

(3)

enhanced

resulted

the blends.

a l .

describing

number o f t r a n s i t i o n

neutralized

mentioned

miscibility

and

a

et

transfer, functional

acrylate-co-4-vinylpyridine),

interactions

and

charge

a c o m b i n a t i o n o f t h e two. 5)

endgroups

(7) r e p o r t e d

poly(vinylpyridine), between

was

or

functionalities,

between t h e polymer

(1).

interactions

specific

functional

Eisenberg

pyridine

polystyrene

amine

and

(4,

(6)

of

generally

interactions

It i s instructive,

amine

incorporating

containing

literature

poly(ethyl

coworkers

et

a l .

used

Clas and

polymers

between

energy

i s

i f exothermic

proton transfer,

paper.

that

miscibility

by

intermolecular

t o enhance m i s c i b i l i t y

interactions,

blends

free

(2).

groups

studies

the

mixing, which

take place

review of the

chloride)

therefore,

occur

formation,

interactions.

poly(vinyl

may

scope of t h i s

several

and,

specific

polymers

functional

specific


t h e two

beyond

of

interactions

comprehensive

mention

small

the enthalpy of

molecular level

hydrogen-bond

specific is

a

dipole-dipole A

by

i n t h e absence

on

groups

i s very

by

the

describes i t s

Cu(II)

pyridine).

EXPERIMENTAL SECTION Carboxyl-terminated Products and

a

I n c . , and weight

concentration solution sodium

was

of the

CTB

which

based

a molar

on

reported molar

d e t e r m i n e d by

hydroxide.

refluxing

a

average

polymer, by

p o l y b u t a d i e n e (CTB) had

to The

mass

mass o f 20%

CTB

obtained

of

9,000. a

contained

4600.

The

solution

4,600

Carboxyl

endpoint with

0.51

meq

average

copper

Scientific

mass o f

group

toluene-tetrahydrofuran

a phenolphthalein CTB

from

average molar

titrating

c o r r e s p o n d s t o a number a

was

number

salt

i n toluene

alcoholic

COOH p e r

functionality ( C T B - C u ) was f o r 24

gram of

of 2.39

formed

hours with


a

14. SEN ET A L stoichiometric Cu(II)

at

under

liquid,

described sodium water.

The

sulfate

as

acetone,

pyridine

persulfate

was

and

carried

The copolymer

dried mass

at

pyridine

nitrogen

in

a mixed

Blends

brownish-green

liquid,

used

and

as

air-dried

were prepared solvent

o f f

under

were

prepared

under

vacuum

Hg

and

terminated

i n a large

with

excess

f o r two days,

had

a number

mass

of and

average

o f 291,000

for calibration.

as The

w a s 3.4 m o l e p e r c e n t

based

reduced

(1)

PSVP/CTB-Cu

(2:1).

I.

pressure. i n

molar

PSVP/CTB

refluxed

The i s o l a t e d Three

parentheses

ratio

(1:1), blends

pyridine

(2) PSVP/CTB-Cu o f these

(1) and

(2)

equivalent

amounts

groups,

blend

(3)

the

equivalence

and

the

Cu(II)

i n

concentration

of

blende

of were

blends

each

groups

(1:1),

blends

stoichimetrically while

CTB-Cu

different

following

of vinyl

The compositions

Note t h a t

of the

f o r 24h and t h e solvent

f o r 24 h o u r s .

(the ratio

endgroups):

a solution

THF (20/80 v / v ) t o a s o l u t i o n

was t h e n

a t 80*C

t h e nominal

pyridinyl

5mm

agent.

molar

by slowly adding

o f toluene and

This mixture

dried

represents

copolymer

at

chain transfer and

PSVP

10%

distilled lauryl

a t 60°C

average

a

sodium

was p r e c i p i t a t e d The

with

initiator,

f o r 24 h o u r s

3 days.

then

distilled

as

dodecylthiol

of the

by

t h e method

T h e s t y r e n e was washed w i t h

and a weight

content

was p r e p a r e d following

analysis.

i n THF.

Table

for

vacuum viscous

b y GPC u s i n g p o l y s t y r e n e s t a n d a r d s

on

distilled

50°C

o f 142,000

distilled

under

was a c l e a r

(PSVP)

was vacuum

out

of i n a

solids.

inhibitor

was

washed w i t h methanol,

determined

in

et a l . (9).

surfactant,

hydroquinone.

vinyl

brown

remove t h e

4-vinyl

reaction

PSVP

t o

was d r i e d

viscous dark

dark

mole

dissolved

The s o l v e n t s were

t h e polymer

copolymerization process,

by Lundberg

Potassium

vacuum

was a h i g h l y

emulsion

endgroups)

T h e a s - r e c e i v e d CTB

were r i g i d ,

hydroxide

30*C.

and methanol.

hours.

( i . e , one-half

acid

poly(styrene-co-4-vinylpyridine)

radical

molar

Cu(II)-acetate

pressure, and

t h e CTB-Cu

The

The

of

water

f o r 24

t h e blends

free


of

reduced

75-80*C

and

amount

a c e t a t e p e r mole o f c a r b o x y l i c

50/50 m i x t u r e off

355

Grafted-Block Copolymer Networks

blend t o

CTB

and

(3)

are

summarized

contained

nominally

pyridinyl

and

ratio

carboxyl

between

i o n concentration

the was

n o m i n a l l y 2:1.

TABLE BLEND wt% Sample

A used two

PSVP

CTB

I

COMPOSITION CTB

ecruiv.

VP

eouiv.

VP

cation

equiv.

COOH

equiv.

Cu

1

56.5

43.5

H

2

56.5

43.5

Cu

0.8

3

72.4

27.6

Cu

1.7

P e r k i n Elmer

differential

t o obtain the glass different

temperature

0.8

scanning

transition ranges:

calorimeter,

temperatures e

-100 C

to

DSC-2,

o f t h e samples e

+10 C

and

-20*C


was i n t o

356


140°C. under a

In the a

nitrogen

range.

midpoint

analyses

thick mm

of

(TMA)

w e r e made heating

temperature

atmosphere

atmosphere

temperature the

low

helium

of

a

flat


air

at

a

Hz

with

change

molded

rate

of

linear

temperature

was

varied.

The

test

mm

under

CuK

the

10m

discs

1.12

m.

dried

probe A

with

a mm

a

Perkin

0.5 Elmer

t o measure t h e

specimens

thermal

were heated

in

System

vacuum

National

counter. e

at

65 C

for

between

four

and

plates.

and

annealed parallel

Center

for

National a

the

Small

Laboratory

rotating

detector

from

in

50°C

parallel

dimensional,

Sample t o

were c u t

used

temperature

monochromatization

a two

a The

stresses.

instrument used and

as

150-200°C

Ridge

source, c r y s t a l

collimation,

oven

m o t o r was

spring-loaded

molded-in

made a t t h e

samples

at

between

For

and

covered.

length

oscillating

molded

residual

The

linear

were conducted

(NCSASR) a t Oak

x-ray

proportional

4

were used

was

1

using

or tension.

specimens

sample

at

spectrometer

i n torsion 50°C

i n the

130°C

SAXS c a m e r a .

Disc-shaped

i n a

at

a p p r o x i m a t e l y 0.9

were used. used

between

at

Research

beam, p i n h o l e

sensitive,

were

mechanical

were compression

0 . 1 5 4 2 nm)

incident

mN

to

of the

i n order to eliminate

(λ =

300°C

to

o f t h e b l e n d s were measured

experiments

vacuum

Scattering

using

measurements

-100°C

rectangular

f o r changes

SAXS m e a s u r e m e n t s w e r e Angle

as

mechanical

TMA-7. T h e

The

4

-100°C

thick

specimens

overnight plates

1

Thermal

from

geometries

and

capability

Torsional

using

plate

of

t o compensate

250°C

upper

Elmer

T 6 A - 7 , was

System

motor

range

auto-tensioning order

while

i n the

were d e f i n e d

a penetration

500

properties

or parallel

the

and

performed

coolant,

10°C/min.

Rheometrics

rectangular tension,

Perkin

of

a

were used

heat.

specimens

force

as

temperatures

of the polymers.

Dynamic m e c h a n i c a l a

a

The

analyzer,

stability

cooler

atmosphere

films,

a

nitrogen

in specific

helium

t i p and

thermogravimetric oxidative

transition

10°C/min.

compression

radius

t h e measurements were

liquid

a mechanical

w e r e made w i t h

under

rate

and

Glass

the

range,

using

anode of

the

position

distance

molded

weeks p r i o r

was

films

to the

and SAXS

analyses· FTIR using

spectra

either

a

were

Specimens were c a s t solvent purged

was

ESR E-3

at

about by

spin

tubes.

The

spectra

were t a k e n

Signal

or

films

four

on

sodium 80 C. a i r .

specimens

25°C

and

FTIR

spectroscopy.

40%

magnetic

field

humidity

(ESR) was

The To

were

made a t x - b a n d

resonance

Cygnus

chloride

e

dioxide-free,

selected

wavenumber

a Mattson

vacuum a t

measurements were

electron

12/70

thin

carbon

re-examined

60-SX

under

to moisture,

environment being

as

removed

with dry,

exposure

obtained with

Nicolet

resolution

spectrometer. discs,

explore the left

i n the

for several

varied

effect

frequency with

from and

0

stored

to

the were of

laboratory

days

spectrometer using

a t room t e m p e r a t u r e

and

spectrometers

before

a

Varian

4mm

5,000

quartz 6.

The

in a Nicolet

LAS

Averager.

RESULTS AND DISCUSSION Both

the

PSVP/CTB

oxidative a

small

and

stability

amount

of

as

PSVP/CTB-Cu shown b y

degradation

the that

blende TGA

exhibited

curves

good

i n F i g . 1.

o c c u r r e d between

350

thermal There

and


was

450*C,

14. SEN ET A L but

the

major

used

to

were

found

latter the

o c c u r r e d about

degradation

most

likely

450°C.

Pyrolysis

products, which

styrene, hydrocarbons

was

thermograms o f

in

Fig. 2

summarized broadened the

Tg,

Two

Tg's

phases

and

i n Table the

due

and

to the

agreed

GC/MS

f o r both

was

blends

1,3-diphenylpropane. presence

observed broadening

of

the

PSVP

a

the

The

of

stabilizer

of

of

the

i n the

in

phase

or

sizes.

blend

the

transition nitrogen

the

metal

since

interaction

this

transition probably

between of

due

The

broadening

was was

the to

rubbery

miscible argument

of

styrene-rich

acid

CTB

phase

miscibility

group

to and

of

CTB

to the an

transition

and

r e g i o n extended

a

single

value

The

however,

be

e x p l a i n e d by

improved

physical

crosslinking

of

and/or

qualitative

apparent

meaningful. may

changes the

TABLE GLASS TRANSITION

PSVP

* **

a

#1

and

acid-base

CTB

and the

Tg.

the glass

This

was

mass CTB in

in

further

i n c r e a s e i n Tg.

Because

over

for

i s not

the the

about

40°C

transition of

the

the

particularly region,

components

difunctional

CTB-Cu.

II THE

BLENDS Tg

CTB-CU

DSC

100.0

-86

100.0

(C) DMA*

-85

CTB-Cu PSVP

blende

resulted

miscibility

PSVP b y

the of

pyridinyl

the

of

%

CTB

CTB

in

than

the

molar

f o r Tg

TEMPERATURES OF

Wt Sample

low

Cu-salt

transition

designation of

salt

CTB

which

formation

decreased

the

for

15*C,

PSVP b r o a d e n e d

the

the

about

than

due

resulted

CTB-Cu

the

were phase

miscibility

have

the

the

stronger

styrene-phase

blends,

some

between

carboxylic

the

have been

by

with for

11)·

a l l

may

only difference t o be

that

i t may

phase

affect

(10,

rubbery

indicate

Substituting

salt

the

i o n and

addition

limited

this

are

copper

polystyrene-rich

Cu(II)

expected

conversion of of

the more

the

of

are

(Tg)

salts

indicated

though

between the

the

The

to the CTB

alternatively,

to the

complex

group.

of

P S V P was

adds weight

T h i s complex

pyridinyl

Tg

blends

significantly

Tg

T h i s may

phase

that

i n the

(PSVP/CTB),

transition. of

raised

not

blend, which

CTB

This

PSVP.

#1

did

CTB

p o l y b u t a d i e n e - r i c h and

f o r each

the

the

and

temperatures

p r e v i o u s r e p o r t s on

small increase

i n blend

of

region, but

distribution

indicated acid.

A

polymers

transition

Conversion

with

were observed

to

#2.

II.

component glass

corresponding to

was

from

the the

transition

which

phase-separated.

the

loss

the

t o be

product

DSC


weight

identify

CTB.

shown

in

357

Grafied-Block Copolymer Networks

100.0

107

1

56.5

2

56.5

43.5

-66/90

-69/116

3

72.4

27.6

**/93

-68/118

taken not

as

the

43.5

maximum

in

-81/82

-76/109

tano

measured


358



100

200

300

400

500

TEMPERATURE (°C) Figure (

1.

TGA

thermograms i n a i r o f

) PSVP/CTB-Cu

J

I 184

170

(

) PSVP/CTB

(1:1) and

(1:1).

I

I 198

I

I 212

I

L 226

240

TEMPERATURE (°K) 1

1

1

1

1

1

1

(b)

1

1

1

PSVP^—-—

—^^^PSVP/CTBiUlJ

ο c

PSVP/CTB-Cu (II )

σ .^PSVP/CTB-Cu(2 1 )

1

1 320

1

1 340

1

1 360

1

1 380

1

1 400

TEMPERATURE (°K) Figure blends.

2.

DSC

thermograms o f component p o l y m e r s

( a ) 170 - 240 R a n d

(b) 310 - 400

and

their

K.


14. SEN ET A L A

comparison

shown by began

the

to

penetrated identical deform In did

TMA

0°C

sample

by

load,

the

about the

Although

at

resistance in

This,

again,

between the strongest DMA

A

were

DSC.

This

but

the

the

higher

the Tg

onset

of

the

taken

as

Tg,

Blend to

about

#1,

Fig.

the

CTB

and

gave

The

increase

the

rise

containing

the

transition

metal

relatively

Thus,

the

4.

a

In

The

that

the

greater versus

modulus

above the

no

Cu-salt, distinct

were vinyl was

a

the

due

to

was

a

a

CTB

at

or

(taken

could

a

measured

rate

broadening

of of

In

be

for

i f

transition

modulus

the were

between

the

a

above

of

the

with

the

the

the

Tg

of

a

of

the

Tg's

for the

Tg. blend

strength of

the

between group.

effective

were

thermally

temperature

transition

demonstrated the

blends

maintained

observed.

maintenance

of

two

higher

the

of

phase.

and

molded.

also

m o d u l u s was

the

interaction

crosslinks

case

containing a

rubbery

the

Conversion

basic pyridinyl had

an

that

g l a s s y phase

greater

compression

was

such

the

phase

the

dynes/cm

consequence of

PSVP,

between

rubbery

2

>10

PVSP p h a s e .

stability In

persistence

value

fact,

achieved

modulus

and

r e g i m e was

The

by

effects,

interactions single

the

the

CTB-salt

complex

blend

as

phase

the

crosslink

systems the

high

the

polystyrene

d e c l i n e i n modulus w i t h

Tg.

DMA

in

lower

the

of

the

the

the

those

of to

likely

region

the

both

flow

data, DMA

experimental

and

the

above the

the

higher

i n the

CTB-Cu w i t h DSC

and

the

dynamic

consequence

relatively

the

CTB.

intermolecular

general,

than

found

most

of

plateau

ionic

p y r i d i n e groups.

of

modulus

increased the

samples

viscous

achieved

than

of

η

Tg

temperature

complex the

to

DSC

assignment

reinforce

containing by

fact

The

physical

stronger

a

the

In

r e g i o n due

weak c a r b o x y l i c a c i d

evidenced

the

to

was

density.

by

I.

Tg's

c o o r d i n a t i o n compared

labile

of

consequence

T h i s was

new

salt

blends

of

they

CTB.

the

DMA.

modulus

crosslink as

a

between the

Cu-salt to

with

two-phase morphology

higher

i n part

above t h e

i n the

a

the

dynamic

and

acted

m a t e r i a l flowed

until

remained

derivative

Like the

measured

PSVP/CTB, m a i n t a i n e d

PSVP g l a s s y p h a s e

to

deformation.

CTB-Cu

PSVP w e r e

an

begin

qualitative,

c o n s i d e r a b l y more ambiguous.

DSC

The

i s

(1:1),

complete

that

formation

i n Table

However,

the

interaction

to

Tg's

b e t t e r agreement

by

100'C,

acid-base

the

the

a l s o be

in

much

the

indicating

T h i s makes t h e

drop

not

blend

free-acid

the

transition

technique

obtained

and

#2

essentially

d i d not

the

the

for association

attributed

polymers.

had

strictly

showed

significantly

temperature

either

values

be

than

the

i s given

d i f f e r e n c e may

two by

of

were

may

were

and

c o n t r a s t , under

#2,

containing

CTB-Cu

Tg's,

tano)

DMA

blend

s h o w n i n F i g . 4.

i n agreement.

measured by

In

#1

PSVP/CTB

polymers.

results

in

#1,

s p e c i m e n was

results

suggested

comparison

maximum

the

blend

evidence

e x h i b i t e d two

blends.

blends

probe

e

359

e x h i b i t e d a more g r a d u a l

containing

strongly

the

deformation

the

blend

of

Blend

120 C.

(1:1),

temperatures to

between

the

i s the

Tg's

the

elevated

those

and

these

that

stiffer

the

PSVP/CTB-Cu 100°C

and about

penetration of

higher

curves

F i g . 3.

about

demonstrate

PSVP

in

at

200°C.

The

softening behavior

the

case,

complex

the

soften

interactions


of

thermograms

through

until

this

about


The

1:1

ratio

of

modulus

of

transition

to

metal by

the

containing 200"C

highest Cu(II)

above the metal


and

values ions PSVP

and Tg

complex

360



TEMPERATURES) Figure (

3.

Figure

4.

temperature (

TMA

thermograms o f

) PSVP/CTB-Cu

(a) Dynamic s t o r a g e f o r (—·.

) PSVP/CTB-Cu

(

) PSVP/CTB

(1:1) and

(1:1).

moduli and

) PSVP,

(1:1) and

(

(

(b) t a n δ

) PSVP/CTB

versus

(1:1),

) PSVP/CTB-Cu

(2:1).


14. SEN ET AL. responsible physical

flow a

high

region

chain

systems


above Tg, and i s

with

more

the

case

of the blends

the

high

degree

These

has

on

considered

here,

eliminated

5

shows

the

IR s p e c t r a l

o f CTB t o f o r m t h e C u - j a l t .

carbonyl

absorption

carboxylate

exposure

for

three

of

there

acid,

·

The

sensitive shifts was

F i g . 5c. blend

films.

the

molded

occurred

absorption

i n the blends

sufficient

at

observation

from

t h e spectrum

was

superficially

absorption

was

confirmed

similar

shifted

by

as evidence phases

changed

t o >1600

CTB-Cu,

significantly

that

that

there

the

that

spectrum spectrum

the

i t s position

local level.

The r e s i d u a l

except

from

highly

Spectral

on a molecular

F i g . 7.

IR

F i g . 6b.

are

s u b t r a c t i o n o f t h e PSVP

blend,

to

moved

environment.

the

the

of the

of the

absorptions

be taken

between

of the the

to

t h e IR s p e c t r u m

was

the

atmosphere

F i g . 6a, and CTB-Cu,

i n the local

g r o u p was

by

reversion

a t 1560 cm"

the

However,

the laboratory

the carboxylate

of the carboxyl

replaced

a superposition

PSVP,

therefore

with

characteristic

, F i g . 5b.

be p a r t i a l

o f CTB-Cu

association

This

to

to

changes

may

associated had a

not simply

of

to structural

changes

F i g . 6 c shows t h a t

was

frequencies

environment

was

by

molded

The a c i d 1560 cm"

salt

appeared

o f i t s component p a r t s ,

The^carboxylate cm

In

manifested

films

, F i g . 5 a , t h a ^ was

a t about

the carboxylate

PS-VP/CTB-Cu

spectrum

a t 1713 cm"

absorption

days,

carboxylic 1:1

the

time

(12)·

by annealing

of

to

associating

processes

a l s o was

of

temperatures.

Fig.

on

attributable

i n other

time

this

shrinkage

viscous

The development

s t r e s s i n t h e compression

severe

when

of the relaxation

longer

reaction broad

observed

these

compression

even though

directly

due t o a broadening

of

that

as during

flowed,

i s not

aspect

fact

experiment.

been

emphasis

s t r e s s e s were

Otherwise,

elevated

which

of molded-in

residual

films.

t h e DMA

the

such

the materials

during

entanglements,

distribution

by

imposed,

361

The l a b i l e

demonstrated were

samples,

not observed

plateau

polymer

was

stresses

of the

was

simple

f o r the physical crosslinks.

crosslinks

relatively molding

Grafled-Block Copolymer Networks

carboxyl

i n the

pure

o f t h e CTB-Cu

salt

material.

that

The

concern

was

raised

PSVP/CTB-Cu Fig.

8

over

blend

Fig.

to

t h e laboratory environment

shows t h a t

carboxylic

acid

carboxylate limited

the hydrolytic stability

by

with

properties

was

time

revealed

of

the

confirmed

there

functionality

functionality

study

5

was

aç

( > 1 7 0 0 cm"' 1

( c a . 1 6 0 0 cm""

).

by

exposure f o r several

apparent )

of

and

a

the days.

reversion

to

reduction

i n

S u r p r i s i n g l y , though,

a

no n o t i c e a b l e d e t e r i o r a t i o n o f t h e m e c h a n i c a l

PSVP-CTB-Cu

blende

after

exposure

to

the

atmosphere. Electron several CTB-Cu

(10,

dimeric Fig.

11,

copper (1:1).

copper

ions

measured

13).

with g = x

reported

to For as

t h e ESR

The

g-Lande

2.320,

those

resonance groups

complexes,

10 c o m p a r e s

CTB-Cu

g„=

spin

research

2 . 0 5 9 , A,,= for

neat

shown

signal

square

factor

the

spectra

strong a

spectroscopy

for near

planar

1 4 5 G,

both

9,

CTB-Cu

and

s t r u c t u r e as

χ

30 + i n

used

by

structure

of

isolated

Blend i n Fig.

5 G, model

and

reported. #1,

due t o

interaction

ions

been

have been

3160 6 was

and Α =

Cu(II)

local

ionomer,

i n Fig.

and h y p e r f i n e

isolated

(ESR) h a s

characterize the

PSVP/

isolated 9a.

The

parameters

were

which

agreed

compounds


with (14).


362


1700

1500

1300

Wavenumber

Figure

5.

exposed

FTIR

spectra

f o r (a) CTB,

t o the laboratory

atmosphere

1700

1500 Wavenumber

Figure

6.

PSVP/CTB-Cu

FTIR

spectra

(cm" ) 1

(b) CTB-Cu, f o r three

and

(c)

CTB-Cu

days.

1300 (cm" )

f o r ( a ) PSVP,

1

(b) CTB-Cu,

and (c)

(1:1).



14. SEN ET A L


Figure minus

7.

FTIR

d i f f e r e n c e s p e c t r u m o f PSVP/CTB-Cu

363

(1:1)

PSVP.

1700

1500

1300

Wavenumber ( c m ) 1

Figure

8.

FTIR

spectra

of

(a) PSVP/CTB

(1:1),

(b)

after

one day exposure t o t h e l a b o r a t o r y

(c)

after

three

days

freshly

made,

atmosphere,

exposure.


and

364


Monomtric

isolottd c o m p l t i t t


Ο

b

Oimtrt (monohydrottd copptr acttott »ypt) H0 2

2

Cu'

Cu *..Cu *:2.64A 2

H0

2

2

C

Otrntrs(anhydrous coppff formott type)

Cu

,0

Cu V.Cu *:3.44A 2

Figure

9.

isolated acetate

S t r u c t u r e s o f Cu

2+

carboxylate

c o m p l e x e s , (b) d i m e r i c type),

formate type). Copyright

1986

and

(c) dimeric

complex complex

(Reproduced with

salts,

2

(a) monomeric

(monohydrated copper (anhydrous

permission

from

copper ref.

10.

Butterworth)



14. SEN ET AL.

365

Grafied-BIock Copolymer Networks

120 1

Λ

CTB-Cu PSVP/CTB-Cu

Grafted-Block Copolymer Networks Formed by Transition Metal

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