Structure-Property Relationships in RIM Polyurethanes - ACS

6 Structure-Property Relationships in RIM Polyurethanes 1

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N.BARKSBY ,D.DUNN ,A.KAYE ,J. L.STANFORD ,and R.F.T. STEPTO Downloaded via UNIV OF CALIFORNIA SANTA BARBARA on July 10, 2018 at 02:18:42 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.

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Department of Polymer Science and Technology, University of Manchester, Institute of Science and Technology, Manchester,M6O1QD, England Department of Mathematics, University of Manchester, Institute of Science and Technology, Manchester,M6O1QD, England

2

Polyurethane (PU) materials have been formed by RIM using a commercial isocyanate reacting with either various compatible or incompatible polyol blends, or with slurries containing polyol blends and glass fibres. The RIM equipment used, modified with a special dosing unit for processing glass fibre/ polyol slurries, is described. Polyol blend composition, varied by using different proportions of high and low molar mass triols and a chain extender, resulted in PUs with various hard block contents and crosslink densities. Tensile, flexural and dynamic mechanical properties at different temperatures have been investigated for the various PUs which ranged (at ambient temperature) from soft elastomers to stiff, yielding plastics. In this study, the use of incompatible polyol blends produced well phase-separated PUs for which the property-temperature dependence (-50 to 100°C) is much less than for PUs formed from compatible polyol blends. At elevated temperatures (>150°C), PUs formed from compatible polyol blends, containing higher proportions of low molar mass triols, retained their mechanical integrity compared with the rapid deterioration, (due to hard-phase melting), observed in the phase-separated PUs. Filled PUs showed the expected increases in stiffness and strength with concomitant decreases in elongation. Property changes in these composites are related to fibre loading and aspect ratio. Formulations f o r producing polyurethanes (PUs) by reaction i n j e c t i o n moulding (RIM) usually contain mixtures of polyols and d i o l s i n order to achieve the desired properties i n the moulded part. The present work forms part U ) of a systematic investigation into the e f f e c t s of polyol blends and glass f i b r e s on the physical properties of u n f i l l e d and f i l l e d PUs formed by RIM. In the case of u n f i l l e d PUs, by using a multi-component polyol mixture, i t i s possible to investigate the effects on properties of (a) polyol structure, molar mass and funct i o n a l i t y , (b) the r e l a t i v e proportions of diol-based hard blocks and triol-based soft blocks and (c) polyol blend compatibility. The

0097-6156/85/0270-0083S06.00/0 © 1985 American Chemical Society

Kresta; Reaction Injection Molding ACS Symposium Series; American Chemical Society: Washington, DC, 1985.

84

REACTION INJECTION M O L D I N G

properties aspect RIM as

of

ratio

filled

PUs

are

determined

(length-to-diameter)

composite materials.

In

either

isocyanate/polyol reactant

used

during

RIM

will

RIM-PU R e a c t i o n The

also

of

case,

ratio,

affect

triol and

VM10

(all

ethylene

containing triol

ICI

PBA1478

catalysts,

tipped with

weight

ratio

and

in

present

POP

is

85:15.

triol

lower

(POE)

molar

it

was

M(720g m o l " )

mass used

thereof,

Two

Series

I:

PUs

using

hammer m i l l e d

glass

milled

(ex.

fibres

of

70um a n d

of

uniform

Series which of

code

polyols

and

including the

ence, a

3%

of

Description ot

is

unfilled the

side

Generally axial

in

to

in

(MDI)

unfilled glass

1

a

chain of

and

26%

olig-

isocyanate

and f i l l e d

(CSG).

mean l e n g t h

Pilkington 17um,

PUs

in

mol" ,

II.

in

The and

order

blends

the

were

various

Table

I,

expressed

stoichiometric of

diamine

in

100),

in

ratios

The

summarised by

(PB)

weight

triethylene

(multiplied

equivalents

diameter

Fibreglass)

throughout.

are

with

hammer

respectively.

of

equival-

isocyanate

and

971

to also not

to

shows require

contain

by

the

a dosing

with

is

thus

of

unit

was

development

polyol

usually used,

unit

simplifying of

the

the

fibres

con-

slurries in

of

and

side.

wear

glass

which,

90

processing

isocyanate

most

parts.

shown


have

commer-

some f o r m o f

special wear-resistant

dosing

the

and r a p i d

unit

of

HP90 m a c h i n e

normal

abrasive

and d i s p e n s i n g

using

throughput the

special dosing

polyol,

the

development

machine, model

right) For

the

1 for

f i l l e d - R I M machines a novel

(top

avoid excessive

metering

pump f i t t e d

diagram of

slurries.

Figure

(mpl)

using

Engineering

a maximum m a t e r i a l

polyol

in

pump

indirectly

machine,

up

would

shown

filled-RIM,

slurries,

Equipment

produced in-house,

1 which

(htp)

that

cially-available, present

as

b a s e d o n VM10

represents

RIM

HP90 w o u l d

tank

be a c h i e v e d

displacement

was

handle

piston metering

tained

5,260g

(EG)

compatible polyol

A schematic flow

1

the to

glycol

catalyst

ratios

1001

of

operating

Figure

PUs,

as

is

(POP) units

isocyanate value

A mixture

used

polyols

w i t h LHT240,

diisocyanate

and

based on a V i k i n g

s~ ).

used

hydraulic

polyol

to

of

in

unit

an

represent

by weighted

materials

(1.5kg

shown

I

of

POP:POE

admixture

(ex.

various

T32/75 Carbide)

hydroxyl.

equipment

capable

dosing

Thus,

T32/75

of

strand

a n d d e r i v e d RIM

excess

(M)

PBA1478

1.5mm

included

Union

with

had nominal

and E G . was

(ex.

and S e r i e s

fibres

Table

and O p e r a t i o n PU

filled-RIM 1

using in

LHT240

System Index.

kg m i n "

Bros.)

isocyanate/hydroxyl

excess

HP90,

PUs

reactants

a 4%

thickness

studies

units,

materials I

and chopped

chopped

dilaurate

1041

A range

RIM

and d i a m e t e r ,

T32/75,

polyol-based as

the

numbers

dibutyltin

the

such

a polyoxypropylene

has

incompatible

(HMG)

Unfilled

the

the

of

(VM10)

Series

Turner

12um: length

II:

series

designated

triol

in

b a s e d on 4 , 4 - d i p h e n y l m e t h a n e

prepared,

these

and e t h y l e n e

1

isocyanate used

in

is

(2)

omers

and

and

in

properties.

an i n c o m p a t i b l e b l e n d

The

were

temperature

b l e n d and D a l t o c e l

LHT240

and T32/75

The

studies

used

extender. and i s

loading

processing variables

materials

polyol

polyoxyethylene

the

of

PBA1478

Polyurethanes),

glycol.

added

the

the

incorporated

Systems

isocyanate,

ex.

by

fibres

mould

final

commercially available materials

Suprasec

primarily

glass

positive In

the

.BARKSBYETAL.

Structure-Property Relationships in RIM Polyurethanes

Nps

F i g u r e 1. Schematic f l o w diagram of the HP90 RIM machine showing the p o l y o l s l u r r y d o s i n g u n i t and o n - l i n e rheometer. Key: h t p , h y d r a u l i c tank ( f o r m e t e r i n g p o l y o l ) ; mp, m e t e r i n g pumps (1 and 2 ) ; JÊpr/hpr, l o w / h i g h p r e s s u r e r e c i r c u l a t i o n loops i t / p t , isocyanate/polyol tanks; i f / i r , isocyanate feed/return l i n e s ; p f / p r , p o l y o l f e e d / r e t u r n l i n e s ; mh, m i x i n g head; mc, mould c a v i t y ; t b , t r a n s f e r b a r r i e r ; h d c , h y d r a u l i c d i s p l a c e m e n t c y l i n d e r ; p s , p r o x i m i t y s w i t c h ; b v , b a l l v a l v e s (1 and 2 ) ; v i s , viscometer.


86

REACTION INJECTION MOLDING Table

I.

Polyol

Blends

and S l u r r i e s to

(i)

= Incompatible

*Slurry

Polyols;

containing

Used

F o r m RIM (c)

18%HMG;

VM10

= Compatible

"^Slurry

Isocyanate

Polyols

containing

5% C S G

System

Polyurethane

Viscosity(25°C)

Polyol Blend/Slurry

with

PUs

Poise

from

Index

VM10

S Ε

PBA1478(î)

11.3

PU1478-97I

R

PBA1478(i)

11.3

PU1478-104I

1041

971

I

PBA1478(i)

11.3

PU1478-114I

1141

Ε

PBA1478-H18*

15.6

PU1478-H18

1041

S

PBA1478-C5+

20.0

PU1478-C5

1041

I S 1? £j R τ

1

1 £i7 o b

PU821

1031

7.8

PU621

1031

PB52l(c)

7.7

PU521

1031

PB42l(c)

7.5

PU421

1031

PB22l( )

4.3

PU221

1031

ΡΒ401^)

11.1

PU401

1031

c

II in

7.7

ΡΒ82ΐ(°) PB62l(c)

greater

transfer slurry

is

ised

bottom ball

nitrile

in up

of

10

(vis)

during

viscometer The

fer

ball

valve

(bv1)

which

of

polyol

for of

The of

system

is

abrasive

fer with

and by

under

flow

through fuller the

slurry. there the

by

are

ensuring

is

less

description

switch

the

the (3).)

a

operates

side

into

the

piston the

trans

and e x p e l l s

the

re

the

transfer

no m o v i n g p a r t s stress, of

total of

equivalent

the

top

swept

the

thus

the

maximum v o l u m e

stroke

an

of

precise

of

minimal

the

the

of

paper

using

(mp1)

Overfilling

that

than

through

viscometer

which

effectively

slurry.

the

expelled

determined

expanded

to

the

(with

from

either

succeeding

advantage of

subjected

controlling

low

The

pressur and

pump

(hdf)

diaphragm is

being of

fluid

a cont

2

is

the

and d i s p l a c e s

with negating

transfer volume of

cylinder

the

of

the

trans

piston

(ps).

During machine operation recirculated

slurry

either

cylinder

proximity

is

valve

(hdc)

hydraulic

prevented

barrier the

nature

in

from metering

polyol

is

tank

and m a t e r i a l

allows or (A

given

by b a l l

areas

that

the

displacement

PUs

expelled

of

shut

by

25°C c a n be

cylinder

polyol

diaphragm i t s e l f

are

which

the

polyol

(hdf)

at

differential

rubber

the

is

slurry fluid

dispensing

amount

barrier

processing

operation

cylinder)

barrier

is

hydraulic

barrier.

quired

dispensing (bv2)

for

(pt)

is

the

fluid

slurry

controlled

valve

(mh)

(allowing

this

During

is

feature

between h o l d i n g

r h e o l o g i c a l measurements.

hydraulic

amount in

of

tank

ball

and i t s

amount

volume the

3-way

Polyol

material

barrier

main

barrier,

displacement

holding

of

the

transfer

diaphragm.

stirred

transfer

head

which

from h y d r a u l i c

1 closed).

the

in the

and f l o w

barrier,

mixing

2

Inside

rubber

bar

the

valve

transfer the

Figure

a separate, to

through

in (tb).

separated

flexible, ained

detail

barrier

but

pressure

prior

to

dispensing,

(independently

of

the

materials mixing


are

head)

to

BARKSBY ET AL.


F i g u r e 2. Schematic diagram of the RRIM d o s i n g u n i t used f o r p r o c e s s i n g p o l y o l s l u r r i e s . Key: p t , p o l y o l h o l d i n g t a n k ; c a , compressed a i r ; sm, s t i r r e r motor; h d f , h y d r a u l i c d i s p l a c e ment f l u i d ; t b , t r a n s f e r b a r r i e r ( n i t r i l e r u b b e r ) ; p s , p r o x i m i t y s w i t c h ; mhf/mhr, m i x i n g head f e e d / r e t u r n l i n e s ; h s , h y d r a u l i c s u p p l y from m e t e r i n g pump 1; b v , b a l l v a l v e s (1 and 2 ) ; v i s , viscometer.


88


ensure

homogeneous m i x i n g

Considering between (bv2)

transfer

as

holding using anate

tank

smooth

machine

a low

through

is

in

The

tank

(pt)

machine in

can then

into

adjustable

Thus, sizes

reactant

orifice

ratios,

to

give

sizes

is

Efficient should

mixing as

is

terms

equation

diameter

the at

annular

the

stream v e l o c i t i e s

of

conditions

ori

mixing about

in

the

100 head

50

an impinge

as

mass

setting

pressure

of

is

the

jet.

(4)

number

orifice

circular

value

the

Q,

the

established,

(Re)

form

the

inser

withdrawn,

number

simplest

d is

orifices

fully

Reynolds

a critical

fluid.

by

psi)

by

circular

the

In

given

the

dia

of

exceed

Reynolds

of

impingement

(pintle

diameter of

a c h i e v e d when f l o w

defined in its

zero

and v i s c o s i t i e s

achieved

(3,000

splits

annular-shaped

a maximum ( p i n t l e

ment m i x e r .

where

through

corresponding reactant

turbulent

fitted

fixed-diameter,

d e f i n e d by the

bar

12mm d i a m e t e r , head

mixing

effectively

throughputs

200

a

varied

pass to

to

potential

can be c o n t i n u o u s l y

streams

to

psi)

mixing

is

head

the

with

moving i n

from

at

enabling 2 pairs

head

(Apr)

and i s o c y

mixing

and i s o c y a n a t e to

The

pintles

impingement m i x i n g

giving

value

orifice

c o m p l e t e l y open)

sizes

polyol

its

loop

m o d i f i e d HP90

with

the

thereby

chamber.

completely shut)

reactant

efficient

of

the

the

valve

be switched

etc.

(3,000

fitted

operation,

streams

c a n be v a r i e d

orifice

MK12-4K-F,

streams

c i r c u l a r mix

a s s e m b l i e s whose

jets.

head,

4

bar

conjunction with

During

through and from

which both p o l y o l

jets/channels

conditions.

recirculated

recirculation

a p p r o x i m a t e l y 200

used i n

piston.

supplies

externally whose

mixing

a Krauss-Maffei

the

nozzle

of

head

metrically-opposed

the

is

pumped t o

pressure

pump ( m p 2 ) .

pressure

mixing

reactant

are

slurry

and h o l d i n g

isocyanate is

r e c i r c u l a t i o n mode

flow

self-cleaning

fice

(tb)

whilst

temperature/viscosity

polyol

c a n be r e c i r c u l a t e d i n d e p e n d e n t l y through

The

With

and s t e a d y

p o l y o l or

through

metering

dispensing

ted,

,

barrier

(it)

pressure

ensure

mix

1

described,

the

a high

Figure

for

flow

and u

throughput

is

of

about in

the

for

a circular

whose

orifice,

dynamic v i s c o s i t y

fluid,

is

g i v e n by

of

the

(5) (2)

where

ρ is

pressure complex simple by

the

drop

fluid

annular

orifice

definition

eliminating

density,

on e n t e r i n g of

d

the

k

is

a nozzle

mixing

arrangement in

Equations

factor

chamber. in

the

and Δ Ρ

However,

Krauss-Maffei

1 and 2

is

is

with

head,

impossible

d can an approximate e x p r e s s i o n

for

Re

the the

and

a only

be o b t a i n e d

Thus, (3) Calculated

values

and m a c h i n e reactants

of

described

During

Re

variables in

using

are

Equation

summarised

Table

in

3

,

together

Table

II

for

with the

materials various

I-

RIM-PU p r o c e s s i n g , t h e

mixing

h e a d was

fixed

to

a


6.

BARKSBY ET AL.

Table

II.

R

e

a

Materials

r

t

a

n

t

.

(ii)

μ

Blends(25°C):

Polyol (i)

and M a c h i n e Parameters

Viscosity,

Reactant

Polyol

(

Q

( f c g

s

_

(kg

1 }

RIM

Processing

Reynolds

ρ

m-3)

Number,

0.345-0.522

1036

270-615

15.6

0.480

1170

206

PBA1478-C5

20.0

0.439

1068

150

0.178-0.238

1220

1980-2291

(700mm)

1.0

steel

to

of

mould

a runner

the

cavity.

The

continuously

increasing

the

about

thickness

in

Typically,

and w i t h Tables

demould

I

times

toughness

Unfilled

range

the of

cessing.

Re

III.

700

χ

and mass filling were

produced

material of

using

during

from reducing plaque

in

was

exotherm

the

mould

reproducible

of

studied. a

1kg

mould

reactants

about RIM

press,

predetermined

systems

throughputs of

length

reaction

approximately

times

used

the

400mm,

of the f o r m u l a t i o n (giving

aftermixer

entire

a hydraulic

polymerising

on PU1478 m a t e r i a l s

Table

Effects

in

70°C w i t h

plaques,

static

the

1s

given

and p l a q u e

processing .

thickness

due

to

alter-

Materials

thickness

Typical

Table

60s

the

U"-shaped,

running

at

plaque

mould

about

result

plaque

columns of

,

f l

clamped

6mm w e r e

each

densities

and II

studies of

1 to

for

a 3mm t h i c k

RIM-PU

Initial erties

the

for

of

a

system

mould,

Rectangular

conditions

with

with water

temperature

150°C.

moulding

fitted

and gate

circulated

and

Density,

Throughput,

)

during

Slurries(25°C):

connected

in

Used

PBA1478-H18

rectangular

ing)

p

4.0-20.0

Isocyanate(35°C):

to

89


tensile III

.

Tensile of

Plaque

(*Filled materials

showed

effects

and System Index stress-strain

Increases, Properties

(23°C)

using

data are

of

on p h y s i c a l

during given

particularly

Thickness,

formed

used

in

incompatible

and

polyol

in

prop

pro

the

modulus,

PU1478

System Index

RIM

first

4

elongation

Materials, Filler b l e n d PBA1478

at

1041) Material

PU1478-

PU1478- PU1478-

PU1478-

PU1478-

PU1478-

971

971

1141

H18*

C5*

2mm

Property

Plaque

1041

y κ

J mm P l a q u e

s

—

Modulus (MN

m" ) 2

296

225

222

289

516

344

Strength πΓ )

21

21

24

27

27

20

Elongation(%)

198

171

158

145

120

53

32

26

27

29

27

8

(MN

2

Toughness (MJ

m"3)


90


ations

in

within

the

(6-8)

the

the

ture

proportionsof

sections highly

gradients

of

skin-co-core layers

these

exothermic

across

the

from the

mould

gelation behaviour

in

surface

to

III

processing (1041

and

decrease modulus

RIM

in

data,

shown

in

terms

the

of

influence

during in

polyol

of

polymer

the

final

blends to

in

the

dispersed T32/75

in

-

tive

purposes,

used

to

to

RIM

blends

soft

blocks

average molar

incompatible on the

Table

1

of

T32/75, hard

HBs

formed

masses

in

the

triol

T32/75

The

curves

and

compati-

block

(HB)

RIM

triol For

PUs

mixtures

between 2,300

composition range.

also

LHT240

these

from

com-

were

maintaining

the

(SB)

and phase

in

whilst

Ideally

(9)

different

based

increasing potential 53%.

same p o l y o l

from

on the

behaviour

PUs

proportions

a n i n c o m p a t i b l e b l e n d PB401

f o r m PU401

to

compara-

( c o n t a i n i n g no LHT240)

and EG r e s u l t i n g

in

a

was

59%

content.

Tensile the

StressrStrain.

progressive

soft,

ductile

change

in

elastomer

the

(PU821)

(PU221).

Preliminary

even phase i n v e r s i o n

the

or

highest

may b e t h e hard

HB

and lowest

result

of

possible

the

degree

polyol

on the

of

blends

similar

tensile

properties

pected PU521

on the

of

the

various

RIM

where

the

effects

of

evident.

(increasing

In

the

an e s s e n t i a l l y

shows in

soft

from the

little

Table

alone

use

IV.

This of

is the

respectively

density)

together

with

PU401

This

is

PU221,

shown

(

molar

43%) for

in

in

PU401. Figure PU401,

incompatibility reducing

increases

in

ex-

compared w i t h

versus with

be

reduced

a n d 59%

compatibility

is deduce

compatible

to

5,300

to

It to

apparent difference

compatible polyol-based series,

crosslink

of

curves

HB-content

PU821

(with

behaviour

continuous

and lower

Behaviour.

phase

phase.

behaviour

a

plastic

PU221

yielding

a n d PU621

from

yielding

1

materials polyol

illustrate

extensive

and the

compensating e f f e c t s

Modulus-Temperature

for

of

PU521

2,000g m o l " )

compared w i t h

4(a) more

the

M)

resulting

summarised

of (

materials

RIM

probably occurred in

stress-strain

PU1478-1041) as

3(a)

of

low m o l a r - m a s s ,

comparison of

basis

triols

a n d PU621

Flexural

to

Figure

indicated that

mixed t r i o l

of

in

series

a high-modulus,

has

phase separation

(itself

mass

studies

dispersed, basis

since

to

plasticisation

phase by a w e l l

not

DSC

shown

second

mixing

M

based

of

in

the terms,

interpreted

on g e l a t i o n

(678).

materials

these

general

c a n be

RIM

with

34

the

later,

PB221 d e f i n e d

PUs

In

modulus-temperature ratio

in is

evaluated from

resulting

weight

the

properties

curves.

4(b)

reactant

of

isocyanate

increases,

f o r m a t i o n , (10)

to

differ-

variations

properties

tensile

PB821

POE/POP

over

1

Index

series

and LHT240 w i t h

1,270g m o l

flexural Figure

produce

(6-8).

toughness,

d e s c r i b e d were

in

range

of

profile

concomitant increases

A second

2:2:1

p r o d u c e s RIM

contents

HB

the

to

and excess

System

stress-strain

Changing the

from 8:2:1

the

(971)

tempera-

thermal

tensile

combination of

and 6 of

PU1478 m a t e r i a l s

investigated.

of

the

with

5

blendPBA1478.

patible

are

under 4,

morphologies The

This

together the

as

on

workers

and complex

PU m a t e r i a l s

compensated by

curves

separation

bility

is

shown

mass,

excess p o l y o l

measured v a l u e s

areas

been

effect

visible

significant

A variable

has

the

the

clearly

shown b y o t h e r

r e a c t i o n causes mould.

of

Generally,

and s t r e n g t h .

these

EG

with

As

and molar

shows

elongation

integrated

polyol

PUs

1141). in

reflected

in

also

PUs.

centre

morphological structure Table

PU

RIM

ences

in

RIM

in


HB

are triol

BARKSBY ET AL.


40i

0 20 40 60 80 100 120 140 160 Strain, 7. F i g u r e 3 . T e n s i l e s t r e s s - s t r a i n c u r v e s (23°C) of RIM PUs defined i n Table I . PUs formed from i s o c y a n a t e VM10 and (a) c o m p a t i b l e and i n c o m p a t i b l e p o l y o l blends ( S e r i e s I I ) ; (b) i n c o m p a t i b l e p o l y o l b l e n d s and s l u r r i e s based on PBA1478 (Series I ) .



Temperature, *C Figure 4. V a r i a t i o n of f l e x u r a l modulus w i t h temperature ( - 3 0 ° C t o 65°C) f o r the RIM PUs i n S e r i e s I and I I d e f i n e d i n Table I . Curves show the e f f e c t s on f l e x u r a l modulus-tempera t u r e b e h a v i o u r and - 3 0 / 6 5 ° C r a t i o s of p o l y o l c o m p o s i t i o n and added f i l l e r s , (a) P o l y o l b l e n d c o m p a t i b i l i t y / i n c o m p a t i b i l i t y : Key: Δ , PU221; A , PU421; • , PU521; O, PU621; · , PU821; Θ , PU401. (b) R e a c t a n t r a t i o (System Index) and g l a s s - f i b r e : Key: 1, PU1478-H18; 2, PU1478-C5; 3 , PU401; 4, PU1478-114I; 5, PU1478-104I; 6, PU1478-97I. (PU401 and a l l PU1478 m e t e r i a l s formed from i n c o m p a t i b l e p o l y o l b l e n d s . )


6.

BARKSBY ET AL. content PUs of

significantly

reduces the temperature

as i n d i c a t e d by the d e c r e a s i n g v a l u e flexural

son of shows

moduli

at

-30 and 65°C

PU221 w i t h PU401 that

93


despite

at

dependence

(50.0 to

(Figure

8.8)

4(a)).

approximately equal

of

these

for

the

However,

HB-content

the domination by c r o s s l i n k i n g

of

the

ratio

compari-

(53-59%) absolute

Table I V . T e n s i l e P r o p e r t i e s ( 2 3 °C) o f RIM PUs Formed as 3mm Plaques U s i n g E i t h e r Compatible ( c ) P o l y o l s o r I n c o m p a t i b l e ( i ) P o l y o l s

^ ^ ^ ^ ^ ^ ^

Material

Property

PU821 PU621

^ - ^ ^ ^

Modulus(MN m

- 2

(c)

)

Yield

Strain(%)

Toughness(MJ

values PU401

of is

ration

flexural

464

818

1280

325

222

24

35

38

26

24

23

33

10

13

-

modulus

-

-

152

130

100

75

147

17

23

23

27

24

28

27

This

a "flatter

indicates

temperature

1 1

the effects

dependent p r o p e r t i e s

(-30/65°C)

uli

from t o r s i o n (G',T)

ratio

respectively. crosslinking

ration

Generally,

having higher state

investigated slightly

of

4.3

in

shows hard

(-180 that

shows The

a distinct contrast, show

two

peaks

200°C,

in

PU821

the G , T

a more

PU621

from g l a s s y On t h e o t h e r

the e f f e c t

apparent

of

and G

1

into

three

soft

behaviour types.

phase Tg at

to-rubbery

of

a broader Tg

is

material

behaviour at

is

about

crosslink

to p l a t e a u whereas

is

densities

6

obser-

in G

to

divides

i n PU221

80°C r e s u l t i n g PU m o i e t i e s

melt. the showing

125°C.

a n d PU421 For

observed between -30 and 70°C

By

which

from extensive

present.

PU221 for

1

c l e a r l y phase separated

apparent

attributable

PU401

temperatures

begins

is

occurs

rubbery

between s o f t and

as the hard phase begins

the various

(0°C and 40°C)

state

but d i s t i n c t

Figure

range

differ

higher

PU401

-

temperature

However,

in

5

sepa-

to

-60°C and a hard phase Tg at

no phase s e p a r a t i o n broad Tg at

phase

a n d PU821

transitional

shown

mod-

5 and 6

and PU421,

of

hand,

der-

Figure

from g l a s s y -

range with a small

gradual

PU221.

increasing

in

PU221

the entire

Materials

70°C.

Figures

no e v i d e n c e

over

lowest

for

storage

to PU221,

However,

show

by the

shear

curves

f

transition

a dramatic decrease

respectively,

a r e shown

between -30 and 150°C.

interaction

and PU621,

200°C).

around

so t h a t

a single,

mental

to

transitional

materials

a single

the t r a n s i t i o n at

a n d PU421 b e c o m e PU401

HB-contents,

only

of

temperatures.

of

sepa-

Dynamic p r o p e r t i e s , terms

the series shifts

dependence

good phase

as e v i d e n c e d

phase s e p a r a t i o n w i t h good m i x i n g

particularly

approaching

in

temperature

evident

distinct phases,

(tano,T)

of

compared w i t h 8 . 8

data in

occurring gradually

a narrower

plateau

ved

to higher

and e x h i b i t

rubbery

over

tangent

and HB-content

progressively despite

pendulum (1Hz)

and loss

-

155

Dynamic M e c h a n i c a l - T e m p e r a t u r e B e h a v i o u r . ived

-

160

modulus,

on temperature

flexural

(i)

(i)

22

m"^)

observed.

(c)

221

2

Elongation(%)

PU1478

P U 2 2 1 PU401

(c)

16

2

Stress(MN m" )

(c)

109

Strength(MN m" ) Yield

PU521 PU421

(c)

seg-

PU821

containing

to phase s e p a r a t i o n between,

T32/75- and LHT240-dominated

PU s e g m e n t s

in

thse


94

REACTION INJECTION MOLDING

F i g u r e 5. The e f f e c t of p o l y o l b l e n d c o m p o s i t i o n on the dynamic s t o r a g e modulus v e r s u s temperature b e h a v i o u r of the u n f i l l e d RIM PUs of S e r i e s I d e f i n e d i n T a b l e I . (Key as i n F i g u r e 4 ( a ) . )

F i g u r e 6. The e f f e c t of p o l y o l b l e n d c o m p o s i t i o n on damping v e r s u s temperature b e h a v i o u r f o r the RIM PUs shown i n F i g u r e 5. (Key as i n F i g u r e 4 ( a ) . )


6.

BARKSBY ET AL.

materials.

The

absence

temperatures

above

phase m e l t s ,

whereas

a

result In

of

the

should

PUs.

bility

the

is

the

level) Phase

network

the

advantages of

is

of

the

of

forming

give

Uniform

logical

initial

SB

slurries

in

slurries

aid

PU1478 m a t e r i a l s ,

summarised increase

shown

in of

Despite

the

decrease the As

the

two

for

higher

filler

is

due t o

expected,

the

as

these it

incompatibility

forming

on the and of

phase-sepa

relative the

solu

various

PU

competing development HB

to

segments w i t h gelation

of

Regarding the

present

polyol

and w e t t i n g

for

of

those

(10).

compatible

slurries

blends

the

filled-RIM

glass

process

p r o c e s s i n g and f a c i l i t a t e as

described

as is

shown

that use

the

result

using

a higher

of

of

in

rheothe

PU1478-H18, the

lengths of

4(b)

than

ratios

unfilled of

the

the

.

The

a much

smaller

materials

is

HMG i n

ob

lengths

(70um)

the CSG. filled

PUs

temperature

PU1478-C5, cf

higher w/w).

(PU1478-H18

PU1478-1041 a r e h i g h e r

for

(3.3

l o a d i n g of

of

of

C S G (5%

fibre

are

greater

result of

be

properties

The

that

much s h o r t e r

those

less

stress-strain

III.

a direct

moduli

Figure

modulus

Table

is

1.5mm

flexural in

tensile

compared w i t h

loading in

slightly

flexural

in

and d e r i v e d t e n s i l e

columns of

compared w i t h

-30°/65°C of

in

However,

incompatible blends,

changes

w/w)

the

HMG c o m p a r e d w i t h

PU1478-H18

or

interpretation,

3(b)

e l o n g a t i o n from

temperatures

for

showed t h a t

PU1478-H18

(10%

and PU1478-C5) of

Figure

last

modulus

served which of

in

HMG u s e d

in

hard

decreasing

Materials

in

loading

at

the

(3).

For

are

prior

filled-RIM

PU

filled

linear

dispersed

and t h e i r

s t i l l

as

phase s e p a r a t i o n

completely filamentising

uniformly

paper

is

compatibility.

and on the

versus

rapidly

present.

reactants

segments,

Filled-RIM

haviour

damping

a prerequisite

formed,

clearly evident

compatibility

essentially

measurements

following

PUs,

indicate that

compatible

were more e f f e c t i v e to

is

increases

crosslinking

polyol

not

on g l a s s - f i b r e

-fibres

PU401

s e p a r a t i o n depends m a i n l y

weights

the

studies

in

damping

other

results

subsequently

molecular

LHT240

i n f l u e n c e d by p o l y o l

parameters

moieties

ing.

in

be emphasised that

(on whatever rated

of

180°C where

much h i g h e r

summary,

s e g m e n t e d PUs

95


as

4.3),

which

the

former.

at

all

dependence

d e f i n e d by again

is

the

the

Literature Cited 1.

2. 3. 4. 5. 6.

Stanford, J . L . ; Still, R.H.; Stepto, R.F.T. In "Reaction Injection Molding and Fast Polymerization Reactions"; Kresta, J . E . , Ed.; POLYMER SCIENCE AND TECHNOLOGY SERIES Vol. 18, p.31; Plenum, 1982. "Technical Data Sheet PU15", ICI Polyurethanes Group, ICI Europa, Belgium. Cross, M.M.; Kaye, Α.; Stanford, J . L . ; Stepto, R.F.T. Following Fruzzetti, R.E.; Hogan, J.M.; Murray, F . J . ; White, J.R. SAE Technical Paper Series, No. 770839, September 1977, Detroit. Schneider, F.W. In "Reaction Injection Molding and Fast Polymerization Reactions"; Kresta, J . E . , Ed.; POLYMER SCIENCE AND TECHNOLOGY SERIES Vol. 18, p.243; Plenum, 1982. Tirrell, M.V.; Lee, L . J . ; Macosko, C.W.; ACS SYMPOSIUM SERIES No. 104, American Chemical Society 1979; p.149.


96 7. 8. 9. 10.

REACTION INJECTION MOLDING

Fridman, I.R.; Thomas, E.L.; Lee, L . J . ; Macosko, C.W. Polymer 1980, 21,393. Carmargo, R.E.; Macosko, C.W.; Tirrell, M.V.; Wellinghoff, S.T. Polym.Eng.Sci. 1982, 22, 719. Stanford, J . L . ; Stepto, R.F.T. Br.Polymer J . 1977, 9, 124. Manzione, L.T.; Gillham, J.K.; McPherson, C.A. J.Appl.Polym.Sci. 1981, 26, 889.

RECEIVED April 16, 1984


Structure-Property Relationships in RIM Polyurethanes - ACS

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