As part of an effort to develop tough solvent resistance thermoplastics for potential use as structural resins on aerospace vehicles, a new processable polyimide was evaluated. The synthesis involved the reaction of a new diamine, 1,3-bis 2-(3-aminophenoxy)ethyl ether, with 3,3',4,4'-benzophenonetetracarboxylic dianhydride to form the polyamic acid and subsequent conversion of it to the polyimide. Various physical properties such as thermal stability, solvent resistance, glass transition temperature, crystalline melt temperature, melt viscosity and mechanical properties such as fracture toughness, adhesive, film and composite properties are reported. Of particular interest is the extremely high titanium to titanium tensile shear strength obtained for this polyimide

Beltz, M. W.

Harris, F. W.

Hergenrother, P. M.

English

NASA Technical Reports Server

c 
(bASA-TM-89253) A NEW R E A C I L Y  € E O C E S S A B L E  
ECLYIBIGE ( N A S A )  11 F CSCL 11B 
G3/27 
A NEY READILY PROCESSABLE POLYIMIDE 
F. W. Harris and M. W. Beltz 
The 'Jniversity of Akron 
Akron, OH 44325 
P .  M.  Hergenrother 
N A S A  Langley Research Center 
Ham t o n ,  VA 23665-5225 
Abstract 
As part  of an e f for t  t o  develop 
tough sol vent resistance thenno- 
plast ics  for potential use as 
structural  resins on aerospace 
vehicles, a new processabl e 
polyimide was evaluated. The 
synthesis involved t h e  reaction 
of a new diamine, 1 ,3-b is  2-(3- 
ami nophenoxy)ethyl ether, w i t h  
3,3 ' ,4,4 ' -benzophenonetetracar- 
boxylic dianhydride to  form the 
polyamic acid and subsequent 
conversion of i t  to  the poly- 
imide. Various physical proper- 
t i e s  such as  thermal s t ab i l i t y ,  
sol vent resistance, g l  ass t r a n -  
si t ion temperature, crystal 1 ine 
me1 ttemperature, me1 t viscosity 
and mechanical properties such 
a s  fracture toughness, adhesive, 
f i l m  and  composite properties 
, 
U n c l a s  
43892 I 
are reported. O f  particular 
interest  in the extremely h i g h  
t i t a n i u m  to  t i t a n i u m  tensi 1 e 
shear strength obtained for t h i s  
polyimide. 
1. INTRODUCTION 
The impetus for research on 
thermoplastic 1 aminating resins 
for  use i n  composite structures 
on aerospace vehicles is lower 
cost. Themplas t i c s  offer less  
waste by virtue of long term 
s t ab i l i t y  under ambient condi- 
tions, the a b i l i t y  to  be repro- 
cessed t o  correct f laws and the 
potential of low cost manufac- 
t u r i n g .  Other properties such 
as sol vent resistance, damage 
tolerance and long term environ- 
mental d u r a b i l i t y  as offered by 
the new toughened thermosets 
https://ntrs.nasa.gov/search.jsp?R=19870001575 2020-03-20T14:04:44+00:00Z
will  a l so  be requi red  of thermo- 
plast ics .  As p a r t  of an e f f o r t  
on thermopl a s t i c  1 amina t ing  
resins, several new semi-crysta- 
11 i ne polyimi des contai n i  ng 
ethyl enedi oxy units have been 
synthesized.1-4 
These materi a1 s were prepared 
from the reac t ion  of various 
aromatic  dianhydrides w i t h  novel 
ethyl enedi oxy conta i  n i  ng  
diamines as showrl i n  F i g .  1. 
T h e  properties of representative 
polymers based upon 3,3' , 4 , 4 ' -  
benzophenonetetracarboxylic 
d i  anhydri de are presented i n  
Table  1. Based upon a combina- 
t i o n  of fac tors  such as 
processabi 1 i ty ,  sol vent resi s- 
tance and a v a i l a b i l i t y  of 
monomers, one polymer, t h e  
subjec t  of th i s  paper, was 
selected f o r  more extensive 
evaluation. 
2. EXPERIMENTAL 
flonomers - 1,3-Bis 2-(3-amino- 
phenoxylethyl ether was prepared 
by t r ea t ing  the sodium s a l t  of 
- rn-aminophenol w i t h  2-chloroethyl 
ether. Recrystall ization from 
ethanol p rov ided  w h i t e  c rys ta l s ,  
mp 101-102°C. 3,3',4,4'-Benzo- 
phenonetetracarboxylic dianhy- 
d r i d e  (STOA) was sublimed a t  
210°C under  vacuum - to  y ie ld  an 
off-white sol i d ,  mp 223-225°C. 
N-Methyl pyrrol i done ( N M P  1 was 
vacuum d i  sti 11 e d  over cal ci um 
hydride. 
Polymer - To a stirred solut ion 
of 1,3-bis 2-(3-aminophenoxy)- 
ethyl ether i n  NW under 
nitrogen, a stoichiometric 
quantity of BTDA as a powder was 
added slowly to  m a i n t a i n  a well 
dispersed reaction mixture. The  
reaction tempera t u  re was 
m a i n t a i n e d  25°C by external 
cooling. After st irring f o r  
2 hours,  a viscous pale  
yellow solution ( so l ids  content 
20% w / v )  formed w h i c h  was 
s t i r red under  n i t rogen  a t  
ambient temperature overnight. 
The  inherent viscosity of the 
polyarnic acid as measured on a 
0.5% solution i n  NMP a t  25°C was 
0.71 dL/g. The polyamic a c i d  
NMP solution Was stirred a t  
200°C f o r  several hours  t o  
a f f e c t  cyclodehydration t o  the 
polyimide. Complete cycl o- 
dehydration t o  polyimi de y ie l  ded 
a meta-stable so lu t ion  where  the 
polymer precipitated a f t e r  
s t a n d i n g  for  several hours. To 
avoid  p r e c i p i t a t i o n ,  approxi-  
mately 5-1oX of polyamic acid 
was l e f t  i n  the polyimide ( a s  
evidenced by infrared spectro- 
scopic analysis)  t o  y i e l d  a 
re1 a t i  vely stab1 e sol u t i o n  
(1 i m i  t e d  ambient temperature 
shelf  l i f e ,  longer i f  refr ige-  
r a t e d ) .  For the preparat ion of 
mol d i  ngs,  the completely cycl o- 
dehyrated poly i rn i  de was used. 
'dhereas, po l y im i  de c o n t a i n i n g  
5: of polyamic a c i d  was used 
t o  prepare f i l m s ,  adhesive tape 
and carbonlgraphi  t e  f a b r i c  
prepreg. Polymer was is01  a ted  
by pour ing the NMP s o l u t i o n  or 
s l u r r y  i n t o  water i n  a blender 
and subsequently washing we1 1 
w i t h  w a t e r  and then methanol. 
The p r e c i p i t a t e  was co l  1 ected 
and d r i e d  i n  vacuo a t  200'C f o r  
2 hours  t o  y i e l d  an o f f - w h i t e  
sol i d .  
Charac t e r i  z a t i  on - Di f f e r e n t i  a1 
scanning c a l o r i m e t r y  (DSC)  was 
performed a t  a hea t ing  r a t e  o f  
20'C/min. The rmogr av i met r i  c 
a n a l y s i s  (TGA) was conducted a t  
a hea t ing  r a t e  o f  2.5°C/min i n  
f l o w i n g  a i r  and n i t rogen.  Wide 
angle x-ray s c a t t e r i n g  (WAXS)  
data was obtained on powder and 
f i l m  specimens. With the x-ray 
d i f f r a c t o m e t e r  operated a t  45 kV 
and 40 mA using copper r a d i a t i o n  
w i t h  a f l a t  sample holder  and a 
g r a p h i t e  monochromator, the 
i n t e n s i t y  of one second counts 
taken every 0.01 degrees (2,) 
was recorded on hard d isk for 
(2,). Me1 t v i s c o s i t y  was 
obta ined on a Rheometric System 
I V  Qheowter w i t h  a p a r a l l e l  
p l a t e  coq f igu ra t i on  w i t h  t he  top  
p l a t e  operat ing i n  an o s c i l l a t -  
i ng mode a t  d i f f e r e n t  f requen- 
c i e s  (0.1 t o  100 radians/sec- 
the  angular range: 10-40' 
ond). The ampl i tude was k e p t  
small ( 0.2%) t o  assure t h a t  
deformat ion d u r i n g  t h e  measure- 
ment occurred w i t h i n  the l i n e a r  
response range. 
F i lms 
Fi lms were prepared by d o c t o r i n g  
NMP polymer s o l u t i o n s  onto p l a t e  
glass, stage d r y i n g  i n  a c i r c u -  
l a t i n g  a i r  oven t o  a f i n a l  
temperature o f  210'C and h o l d i n g  
a t  210'C f o r  2 hours. Mechani- 
cal  t e s t s  were performed 
according t o  ASTM D882. 
Yo1 dings 
I n  a 1.25 in.  square s t a i n l e s s  
s tee l  mold, polymer powder was 
compression molded a t  250'C 
under 100 ps i .  Four compact 
tension specimens approximately 
0.62 in .  x 0.62 in .  x 0.37 i n .  
t h i c k  were c u t  from the  molding 
and f r a c t u r e  toughness (GI~, 
c r i t i c a l  s t r a i n  energy re lease 
r a t e )  determined f o l l o w i n g  t h e  
procedure i n  ASTM E399. 
Adhesive Specimens 
Standard t e n s i  1 e shear specimens 
(bond area 1 in. wide x 0.5 i n .  
over1 ap) were f a b r i c a t e d  us ing  
t i t a n i u m  (T i ,  6A1-4V) adherends 
having a Pasa J e l l  107 (Products 
Research and Chemical Corp., 
Semco D i  v . s u r f  ace treatment. 
* 
4 
The subs t ra te  
d i l u t e  NMP 
was pr imed w i t h  a 
s o l u t i o n  ( 5% 
s o l i d s )  o f  the poly imide and 
d r i e d  f o r  1 hour a t  210°C. 
Adhesive tapes w i t h  (50 phr)  and 
w i t h o u t  powdered a1 umi num MD105 
f i 1 1 e r  were prepared by nu l  t i p 1  e 
brush c o a t i n g  o f  NHP s o l u t i o n s  
(20 s o l i d s )  onto 112-E glass 
w i t h  an. A-1100 f i n i s h .  The tape 
saw a f i n a l  d ry ing  c y c l e  o f  
210°C i n  vacuo f o r  6 hours. 
< 0.3%. Specimens were f a b r i -  
cated i n  a press by hea t ing  t o  
260OC dur ing  45 min. under 
100 p s i  and ho ld ing  a t  26OOC 
under 100 p s i  f o r  1 5  min. 
T e n s i l e  shear specimens were 
t e s t e d  according t o  ASTM D1002. 
i J n l 3 + 4 1 -  r n m + n m t  n G  +I.- 4%"- i u i a c i  1 5  LUI IW=I IC  UI ~11s cap= bias 
ComDosite SDecimens 
Carbon/graphi t e  f a b r i c  (Cel i on 
3KT, BMS 9-8B) was s o l u t i o n  
coated several t imes w i t h  an NMP 
s o l u t i o n  ( 15% s o l i d s )  o f  the 
po ly im ide  and subsequently d r i e d  
a f t e r  each coat. The r e s u l t i n g  
prepreg a f t e r  a f i n a l  dry a t  
225OC f o r  3 hours i n  a i r  had a 
r e s i n  content  o f  41% and a 
v o l a t i l e  content o f  1.5%. E i g h t  
p l i e s  of the prepreg were 
stacked i n  a s t a i n l e s s  s tee l  
mold and press cured f o r  0.5 
hour a t  26OOC under 200 psi .  
The composites (3  i n .  x 7 i n .  x 
0.110 in .  t h i c k ,  r e s i n  content 
o f  37%) were c u t  i n t o  specimens 
and t e s t e d  f o r  f l e x u r a l  proper-  
t i e s  and s h o r t  beam shear 
s t r e n g t h  according t o  ASTM D790 
and D2344 respec t i ve l y .  
3. RESULTS AND DISCUSSION 
High mol ecul  a r  weight polyami c 
a c i d  was r e a d i l y  prepared i n  N?l? 
from the r e a c t i o n  o f  1,3-bis 2- 
(3-aminophenoxy)ethyl e ther  and 
BTDA as represented i n  F ig .  2 .  
was a f f e c t e d  chemical ly ( a c e t i c  
anhydr ide and p y r i d i n e )  and 
the rma l l y  ( h e a t i n g  t h e  NP?P 
s o l u t i o n  t o  200°C f o r  several 
hours or by d r y i n g  a f i l m  a t  
210OC). The r e s u l t i n g  poly imide 
was semi - c r y s t a l  1 i ne as i n d i c a t -  
ed by WAXS (Fig.  3) and DSC 
(F ig .  4 ) .  The poly imide has a 
c r y s t a l  1 i n e  me1 t temperature 
( T m l  o f  242°C and a g lass 
t r a n s i t i o n  temperature ( T g l  o f  
150°C (F ig.  4 ) .  A f t e r  t h e  
Tm has been exceeded, thermal 
anneal i ng f o r  several  hours a t  
210°C was unsuccessful i n  
i nduc ing  c r y s t a l l i n i t y .  T h e m -  
g rav ime t r i c  ana lys i s  curves 
(F ig .  5) showed 5% weight l o s s  
i n  a i r  and i n  n i t rogen  a t  373 
and 408OC respec t i ve l y .  The 
m e l t  v i s c o s i t y  o f  f u l l y  im id i zed  
amorphous poly imide measured a t  
210°C was 6 x 106 poise a t  a 
frequency o f  0.1 radianslsec and 
1 x 105 poise a t  a frequency o f  
100 radians/sec. The m e l t  
r..-i r ~ r ~ . . ~ - . ~ ;  
~JL IUUCI IJUI  abiuii cu p u i j  I I I I IUC 
v i s c o s i t y  curves of the po ly -  
imide, UDELe P-1700 po lysu l  fone 
and U1 t e M  1000 po lye the r im i  de 
a re  shown i n  Fig.  6. 
Our work p r i m a r i l y  i n v o l v e d  t h e  
p o l y i m i  de prepared by thermal 
c y c l  odehydration o f  the polyamic 
a c i d  i n  NMP. When e s s e n t i a l l y  
100: i m i d i z a t i o n  was a t ta ined ,  
NMP s o l u t i o n s  ( 10 t o  Z X  
so l  i ds content )  o f  the r e s u l t i n g  
Dol y i m i  de were meta-s tab1 e 
forming a t h i c k  s l u r r y  ( p r e c i p i -  
t a t e  of g e l - l i k e  consis tency)  
upon standing. With heat, the 
s l u r r y  formed a c l e a r  s o l u t i o n  
which upon coo l i ng  and s tanding 
again became a s l u r r y .  When 
5-10s o f  polyamic a c i d  was 
l e f t  i n  the poly imide, the 
s o l u t i o n  was moderately s tab le.  
T h i s  so l  u t i  on remained stab1 e 
f o r  weeks when c o l d  whereas a t  
ambient temperature, t h e  
s o l u t i o n  formed a t h i n  s l u r r y  
a f t e r  several days. This  s l u r r y  
c o u l d  be transformed back t o  a 
s o l u t i o n  upon heat ing and again 
t h e  s o l u t i o n  was s t a b l e  a t  
ambient temperature for several  
days (dependent upon the e x t e n t  
o f  i m i d i z a t i o n ) .  
Transparent ye l l ow  f i l m s  c a s t  
from NMP so lu t i ons  o f  95% 
i m i d i z e d  polymer and subsequent- 
l y  d r i e d  a t  2 1 O O C  gave t e n s i l e  
s t reng th ,  t ens i  1 e modul us, and 
e l  ongat ion respec t i ve l y  a t  25OC 
o f  12,500 p s i ,  391,400 p s i  and 
4.0% and a t  93OC o f  9,500 p s i ,  
291,000 ps i  and 5.0%. F i l m  
specimens (0.125 in .  x 1.0 i n .  x 
0.002 in. t h i c k )  were bent back 
upon themselves and placed i n  
t h i s  s t ressed c o n d i t i o n  i n  j e t  
f u e l ,  d e i c i n g  f l u i d ,  and hydrau- 
l i c  f l u i d .  A f t e r  24 hours o f  
imnersion, no de tec tab le  sensi -  
t i v i  t y  was observed. However 
a f t e r  only a few minutes o f  
exposure i n  methylene c h l  o r i  de 
( p a i n t  s t r i p p e r  component) , 
pronounced c r a z i n g  was observed. 
Transparent orange mol d ings were 
f a b r i c a t e d  a t  26OOC under 100 
p s i  and c u t  i n t o  compact tens ion  
specimens. F r a c t u r e  toughness 
( K I ~ ,  c r i t i c a l  s t r e s s  i n t e n -  
s i t y  f a c t o r )  a t  25OC was 2670 
ps i  i n  and f r a c t u r e  energy 
(GI~, c r i t i c a l  s t r a i n  energy 
re lease r a t e )  a t  2 5 O C  was 18.2 
i n .  l b . l i n .2  The surface o f  t h e  
f a i l e d  specimens was h i g h l y  
crazed and moderately rough due 
t o  y i e l  ding. For compari son, 
t he  G I ~  o f  UDEL* P-1700 poly-  
su l fone was 19 in. lb. / in.2 and 
o f  U1 ten@ 1000 po lye the r im ide  
was 21 i n .  lb./ in.2 
Standard T i / T i  t e n s i l e  shear 
specimens were f a b r i c a t e d  a t  
26OOC under 100 p s i  and t e s t e d  
t o  prov ide the  p r e l i m i n a r y  
adhesive data i n  Table 2. The 
2 5 O C  average T i / T i  t e n s i l e  shear 
s t r e n g t h  of 
e x c e p t i o n a l l y  
h i g h e s t  Val ue 
s i n g l e  l a p  
f a i l u r e  mode 
7850 p s i  was 
high, perhaps the  
ever repo r ted  f o r  
specimens. The 
was essen t ia l  l y  
100% cohesive. Strengths a t  
o t h e r  c o n d i t i o n s  were a1 so 
e x c e l l e n t  w i t h  t he  except ion o f  
72 hour water b o i l .  The problem 
however was a t  t he  i n t e r f a c e  
(adhesive f a i l u r e )  and not  w i t h  
the poly imide. Powdered 
aluminum f i l l e r  r d u r p r i  t_hp 2 5 O C  
s t r e n g t h  somewhat and improved 
the 121OC s t reng th  s l i g h t l y .  
Small g r a p h i t e  f a b r i c  composites 
f a b r i c a t e d  a t  26OOC under 200 
p s i  gave 25OC f l e x u r a l  s t rength,  
f l e x u r a l  modulus and s h o r t  beam 
shear s t reng th  of 70,500, 
7,300,000, and 4100 p s i  respec- 
t i v e l y .  No t e s t i n g  was done a t  
e leva ted  temperature due t o  the 
low numbers obtained a t  25OC. 
The exact  cause o f  the low 
numbers i s  n o t  known since the 
g r a p h i t e  appeared t o  be wetted 
w e l l ,  r e s i n  content  was accep- 
t a b l e ,  and the o v e r a l l  q u a l i t y  
of t h e  composite appeared good. 
The composite p r o p e r t i e s  were 
expected t o  be good based upon 
the adhesive proper t ies.  Other 
composites w i  11 be f a b r i c a t e d  
from prepreg coated w i t h  po ly-  
amic a c i d  s o l u t i o n  and subse- 
quen t l y  d r i e d  under cond i t i ons  
t o  cause i m i d i z a t i o n .  
4. CONCLUSIONS 
A new -poly imide was synthes ized 
which e x h i b i t e d  r e s i s t a n c e  t o  
h y d r a u l i c  f l u i d ,  e x c e l l e n t  
processabi 1 i ty, and e x t r a o r d i  n- 
a r y  adhesive strength.  
5. REFERENCES 
1. W. A. Feld, B. Ramalingam 
and F. W. Ha r r i s ,  J. Polym. 
319(1983) 
2. F. W. Ha r r i s ,  M .  W. B e l t z ,  
S. Das and R. K. Gupta, 
, Polym. Prepr.. 
160 ( 1984 1 
Karnavas, C. N. Cucuras and 
S. Das, Polym. Prepr. - 26(2), 
287 ( 1985) 
Karnavas, S. Das, C. N. 
Cucuras, and P. M. 
Hergenrother, Polym. Mat l .  
Sci .  Eng. Proceedings - 54,
89 ( 1986 1 
sei=, Pnlym, Chem: Ed: - 
- 
3.  F. W. Harr is ,  A. J. 
4. F. W. Ha r r i s ,  A. J .  
6. BIOGRAPHIES 
Frank W. Ha r r i s ,  Professor  o f  
Polymer Science a t  the Univer-  
s i t y  of Akron, received a B.S. 
degree from the  U n i v e r s i t y  o f  
Missour i  and M.S. degree and 
Ph.D. from the U n i v e r s i t y  o f  
Iowa. D r .  H a r r i s  was P ro fesso r  
a t  Wright State U n i v e r s i t y  f rom 
1970 t o  1983 and became 
associated w i t h  the  l l n i v e r s i  t y  
o f  Akron i n  1383. H is  work has 
been p r i m a r i l y  i n  the  area o f  
c o n t r o l  1 ed re1 ease of b i o a c t i  ve 
mater i  a1 s and h igh  performance 
func t i ona l  and s t r u c t u r a l  
polymers. 
X '  
Mark il. Be l t z ,  graduate s t u d e i t  
working towards h i s  3h.3. a t  t h e  
,n i ve rs i t y  o f  Sk'3rl ui",r 
3 r .  ' ra ik  'd. H a r r i s ,  received 
h i s  3.5. degree f r3T d i l m i n g t o i  
Eo l lege and Y . S .  degree f rom 
a r i g h t  S ta te  L ln ivers i ty .  L i s  
work has been p r i m a r i l y  i n  h igh  
performance polymers where he 
has coauthored several papers. 
Tg, OC Tm, OC Tg. OC Tm, OC 
Paul Y.  Hergenrother, Senior 
Polymer S c i e n t i s t  i n  t h e  
Mater i  a1 s D i  v i  s ion,  N A S A  Langl ey 
Research Center, rece ived a 
B.S. degree from Geneva Co l lege 
and took graduate work a t  t h e  
U n i v e r s i t y  of P i t t s b u r g h  and 
Carnegie Me1 1 on l l n i  v e r s i  t y  . He 
h e l d  va r ious  techn ica l  and 
management p o s i t i o n s  a t  Ye1 1 on 
I n s t i t u t e ,  Yoopers co. ,  
i l h i t t a k e r  Corp. (?!I3 3 i v . )  and 
Boeinq Aerospace 20. a i d  was an 
Adjunct Research ?rofessor w i t h  
V i r g i n i a  Po ly techn ic  I n s t i t u t e  
and S ta te  Y n i v e r s i t y .  H is  work 
has Seen p r i m a r i l y  i n  the  area 
o f  h igh  performaice palymers. 
2 
3 
TABLE I ETHYLENEDIOXY POLYIMIDES 
155 2 36 
- - 
1 1 191 290 I 246 460 
235 4 10 
200 395 
TABLE 2 TUTi TENSILE SHEAR STRENGTHS 
F I L L E R  1 TEST COW D I T IO11 1 T E N S I L E  SHEAR ST., P S I  ( F A I L U R E ) '  
MONE 
M PHR B0105A~ 
25°C 
93'C 
121'C 
25°C 
93°C 
121'C 
25'C AFTER 3 DA k 0  B O I L  
25°C AFTER 3 DA h 0  B O I L  
7850 (COH) 
3040 (ADH)  
4045 ( C O H  + T P )  
6200 ( C O H )  
3610 ( A D H )  
5030 ( C O H )  
4300 (Con) 
5400 ( C O H )  
'PASA-JELL 107 SURFACE TREATBENT, 25°C 260°C UNDER 100 P S I ,  HOLn 15 1IN 
'COH = COHESIVE,  ADH = ADHESIVE,  AND TP = THERnOPLASTlC 
FIG. 1 SYNTHESIS OF ETHYLENEDIOXY POLYIMIDES 
0 0  
/II\ / 1 1  \ 
0 0  
n O,I,/Ar' ,,,, 0 + n ~ ~ 1 -  + NH2 oc H~ c H~+- o  
X 
1 
@OCH C H t O  
II II 
HN-C\ , /C -NH 
H O Z C / ~ '  \COZH 
2 2 x  
x = 1 t o 4  
b 
. 
FIG. 2 SYNTHESIS OF ETHYLENEDIOXY POLYIMIDE 
0 
I I  
0 
I I  
0 0 
Polyamic acid 
-2nH20 i 
0 0 
FIG. 3 WIDE ANGLE X-RAY DIFFRACTOGRAMS 
Relative 
in t en  s ity 
LFi lm dr ied at 2103C 1 
I 1 
10 15 20 25 30 35 
Di f f ract im anqle, 28 
J 
' '  b 
m 
100- 
90 
80- 
70 
60- 
i"eiqht 
% 
retent ion.  50 
40- 
30 
FIG. 4 DIFFERENTIAL SCANNING CALORIMETRIC CURVES 
\ \ m0c ---- - - -_ 
\ - 
373OC 
- 
- 
I 
I 
I 0 
- 
0 0 
I 
0 
t! 
c t
a 
Run 
After 
Heating rate: @Clmin 210% 
Sample size: 7.8mg 
Atmosphere: Static a i r  
Sensitivity: (lrncah'sec Vin. 
1 
heating at 
for l5 min. 
- v2 'c243 Run 2 - After heatins ts 303% and slowly cooling 
U 
1 I I I I I I 
U 
50 100 150 2W 250 300 350 400 
Te npecatu re, OC 
FIG. 5 THERMOGRAVIMETRIC ANALYSIS CURVES 
10 
*O 1 Heating rate: 2 5 0 ~ / ~ 1 i n  Sar,ple f3rt-n: powder I I I \ \ 
I I 1 I I I I 1 '-* 
0 50 100 150 233 250 303 350 400 450 500 550 600 050 7% 
Tenperature. OC 
FI 
L' iscosity , 
poise 
IG. 6 MELT VISCOSITY OF THERMOPLASTICS 
I I I I r , ,  108 I 
i 
i t mg WC. run 6 2 1 0 " ~ )  
M". 29,500 i 
1 104 I L , 1 1 1 ,  
0.1 1 10 
Frequency, radisec 
100 


A new readily processable polyimide

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