Char yields of synthesized crosslinked polymeric azomethine

Dalelio, G. F.

Feigl, D. M.

Kieffer, H. E.

Mehta, R. K.

English

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a 
THE DIRECT S'kTU'HESfS OF CROSSLXNKEU POLkW.XIC AZOXETHTNES . 
G.F. D'Alelio, D-Nn Faigl., R.E. Kief fe r ,  and. B.R. Xchta., 
Departnvznt: of Chemistry, Univezstty of Motre Daze, Notre Dame, hd i . ana  45556 
N5C.- 3 SF 
Polymers which y i e l d  a high amount of char  res idue  a t  r e l a t i v e l y  high 
temperatures are of i n t c c e s t  i n  bn,sospac~ rechno1.ngy as char r ing  ab la to r s .  
Generally, t he  higher  t he  tk?ermal s t a b i l i t y  of  t he  polymer, t h e  higher  the 
y i e l d  of char ,  A number of high p ~ t f ~ n i l c ~ i i c e ,  therxrd ly  ssable polymers, 
such as the polyiniides, polybenzimidaxoles, polyimidazopyrrolones, pof j -  
azoulet'nfnes and o the r s ,  have been syntlicsi.zed i n  recent  years .  These n2w 
p ~ l p ~ r ~  are usual ly  w r i t t e n  as having cEle ncrrnally c lassical .  l i n e a r  s t r u c -  
t u r e s $  yet  they prodluce h igher  y i e l d s  of c h r  than t h e  crossl.i.nked phai1olic 
r e s ins .  
suffi .cient1y stable i n  the  region of 330 to 4.00"C so t h a t  r i ngs  o r  c ross -  
links could be generated by h c e r -  or inf:rat<olecuLar reac t ions  a t  these  and 
higher  temperatures, thereby s t a , b l l i z i n g  the  polymers t o  higher  teurperaturcs . 
The t h e m a l  s t a b i l i t y  i s  the i tx iAcnta1  C Q I I S E ( ~ ~ L X ~  of t h e  thermai treatmctnc 
oE t h e  polymer, The l i t e r a t u r e  appears t o  be neg l ig ib l e  on the in f luence  of  
de l iberace ly  introduced crossl i .nks on the. char  y i e l d  of thermally s t a b l e  
normally "l inear"  poljmers . 
dates t o  determine t h e  changes t h a l  m u l d  result i n  char  y i e l d s  by the  
d e i i t e r a t e  in t roduct ion  of crosslknlcs i n  the; P s t ruc tu res .  T h e  l i n e a r  re fcc -  
Eigh char y i e lds  would be cxpected if t h e  l i n e a r  chains  were 
Accordingly, a number of p o l y m r i c  szoaethines were se l ec t ed  as candi- 
ence ~ o l y m e r  se l ec t ed  for thLs s t r : d y  was the. polyketan i l ,  4 p --.CcH[+ p s=NC~QtNzg 1 
prepared from 1 , ~ - C K ~ C O C ~ H ~ C @ C B ~  and 1,3-N$c&t4a2, and wits considered 8s. 
having a crossZink d e n s i t y , p ,  of zero. 
prepared from equivalent: quai-t t l t ies of 1 , 3 , 5 - C ~ i 3 ( C O C ~ 3 ) 3  and 
1,3,S-C683(MR2)3 were considered as one, since every e f f e c t t v c  bard prou16 
lead t o  ii c ross l ink ,  Two series 0 5  poiyaers w i t h y  value between zero and 
one were prepiircd 1 3,5-C& (COC133)g w a ;  used w i ~ h  
the pa t r  1,4-C;I93COCgH460CHq a d  1,3-C&c(Nfi2)  2 t o  introduce t h e  cross3inks 
so that t b e p v a l u e s  were 0.00; 0.05; 045; 9.50 and 1,OO. 
I n  t h e  second series, L,3,5-C&23(EW2)3, was used ,as t h e  c ross l ink ing  
agent t~ give  va lues  correspondins  t o  t h . ~  po l jne r s  of t h e  f i r s t  series. 
A l l  of the  po P .ynners ~ z m a  prepared by m e l t  condmsat ion under n i t rogen  at 
atmospheric pressure. at t h e  fisLl0wing t i m - t e q m x i t u r n  schedule: two hours 
at 180°C; two hours at 225°C; seventeen house at 325°C and two an& om-ha i f  
hours a t  400°C; t hese  polyners  tire desigearecl as H400 polymers. The eie- 
mental analyses 02 the !%O0 polymers wece i n  good agreeinent w i t h  theory.  
The yield,? of the H400 polp.ers o b t a i n 4  froxi t he  uncatalyzed r eac t ions  
were f G u n d  tu ii:crease w i t $  an increase  Ln the mount  of t r i f u n c t i o n a l  
c ros s l i rk lng  agent but t hese  yields w e r e  lower than the  y i e l d s  obtained Etrom 
the zinc chlor ide  ca ta lyzcd  reactioiis, The y i e l d s  of t h e  catalyzed r eac t ion  
alsc increased wich ail increase  in catalyst :  concentrat ion.  
catalyzed by 0.01 mole of z inc  ch lo r ide  par mole a f  ctotal r eac t an t s  increased 
from 36% for systems o f f  = 0 t o  PU09/0 for,.@ -1 1. 
analyses  0x1 10 mg s aq le s  grr~und t o  a fine pcigder of approximately 500 
pieces a.t iz h e a t h g  r a t e  of EO"@ per minut2 i n  ni t rogen a t  B flow rate o 
one standard l i t e r  per  ntjnutre. 
were higher than. those of p = 0. 
' 
In t h i s  paperr t h e f  value p~lyncrs 
In  t h e  first seri 8s 
The y i e l d s  
The char y i e l d s  o f  t h e  p01p.et.s were determined by therniogravimetric 
The char  yields of the  polymers off > 
T y p i c a l  values were: 
Per Cent C&e.r a t  "C 
p 4QO 600 8@0 1309 1176 
0.0 97 84 74 7 2  67 
0.025 97 87 81 7 9  75 
I --------,.----- 
Port ions of t h e  H4GO p o l p e r s  were posLheited under n i t rogen  f o r  twent 
minutes at: 60CO.5; cordi t roi ls  vhLch have k e n  st..oi,m t o  y i e l d  polynuclear 
c o n d e ~ i ~ a t i o n  products ,  These p~lym.;rs are designated as HfOO polymers. 
The weight l o s s  urider tkese  c ~ ? ~ * . S . t f o n s  .fur po3.yn;ers of = 0 was about 14.5%, 
which w w  sli@itl>r higher  than the 109: f~ C ~ C  :.elat@d PO cs @fp > 0. 
fl. F, 
M h  L f l  
https://ntrs.nasa.gov/search.jsp?R=19680024043 2020-03-12T06:27:12+00:00Z
The char  y i e l d s ,  dete.rmi.ned l-he~it!oSr~virt i~tricalry,  were s u b s t a n t i a l l y  
ident ica l  for all1 cf t h e  E609 po3yir.ep.s, ranglng from 86 t o  88% a t  1176OC. 
A t y p i c a l  va lue  for the  H600 poiy:ers is 
Temperature O C  
--I___*)--.- - 
Wi!".--.---- 709 900 1000 1176 
% Char 100 S8 93 9 2  88 
I n  t h e  H400 polymers, t h e  d e l i b e r a t e  in t roduct ion  of c ros s l inks  corxes- 
ponding t o p  = 0.05 increased t h e  rcnixm'z of char  remaining at 1176°C by 
about 12% above t h e  char  va lue  found for p o l p e r s  ofp E=: 0; f u r t h e r  in -  
creases i n p  above 0.05 d id  not increase  the  char  y i e ld .  
i nc rease  i n  char  y i e l d  was found i n  t he  E600 polymers w h e n p  was increased 
fro3 0 to 1. 
pe r  cent conversion i n  t h e  condensation. polymerization s t a g e  t o  40Q"C, 
losses i n  t h e  pos thea t ing  at: bOO"C, and the per  cent  char  r e s idue  a t  1176"C, 
an herease i n  t h e  c r o s s l i n k  dens i ty  frcm 0 t o  1 yie lded  an increase  ia 
char O €  about 13% i n  t h e  H400 polymers acid a.Sout 7% i n  t h e  H600 polymers, 
I n  c o n t r a s t ,  IXQ 
However, when t o t a l  y i e l d s  were ca lcu la t ed  on t h e  b a s i s  of 


The direct synthesis of crosslinked polymeric azomethines

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