Method of incorporating ether linkages into perfluoroalkylene segment of a dianydride intermediate yields intermediate that may be used in synthesis of flexible, stable polyimides for use as high-temperature, solvent-resistant sealants

Webster, J. A.

English

NASA Technical Reports Server

March 1973	 B73-10080 
NASA TECH BRIEF 
•	 Marshall Space Flight Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
A New Intermediate for the Production of 
Flexible Stable Polymers 
S
The problem: 
A number of polyimides have been prepared and 
studied for use as high-temperature, solventresistant 
sealants. Some of the most promising candidates have 
included aryl-fluorocarbon groups to increase the solvent 
resistance of the polymer. Dianhydride intermediates of 
the form 
O	 (CF2)	 ,0 
0
 / : 01 - , '(1X \0 (1) 
have been used in the synthesis, but the resulting 
polymers are insufficiently flexible for use as sealants. 
The solution: 
A method of incorporating ether linkages into the 
perfluoroalkylene segment of dianhydride (I) above 
yields an intermediate that may be used in the synthesis 
of more stable polyimides having increased flexibility. 
How it's done: 
The synthesis yields ether-linked aryl tetracarboxy 
dianhydrides of the structure: 
(C(2)n °N(C
(H) 
O	 0 
The synthesis steps are outlined below: 
0	 0 
II	 II 
OH + dC (CF2)3CCI 
CF3
0	 0 
II	 II	 SF, 
CF 3 ..00 (CF2 ) 3
 CO	 CF3 
CF3
	 1::^CF3 
CF 3	 0 (CF2)5	 H2SO4/C1SO3H O-,CF3 
CF3	 CF3 
HOOC	 0 (CF 2 ) 5
 O,-COOH —2H20 
HOOCX( 	 L,LCOOH
0 
(CF 2
 ) 0
(II) 
loll
0 
The acid chloride-hydroxyl group reaction and the 
SF4
 fluoridation are fairly straightforward. However, the 
preferential hydrolysis of the aryl-CF 3
 to COOH without 
attack on the aryl-OCF 2
 linkage, the essential feature of 
the synthesis, has not previously appeared in the 
literature. 
The effect of the ether linkage on polymides in-
corporating structure II may be seen in the change in the 
glass transition temperature. Polyimides with structure I 
have transition temperatures in the range of 60 to 65° C; 
those with structure ii in the range of 40 to 45° C. 
is	 (continued overleaf) 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States 	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19730000080 2020-03-17T06:43:44+00:00Z
Note: 
No further information is available. Specific ques-
tions, however, may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Code A&PS-TU 
Marshall Space Flight Center, Alabama 35812 
Reference: B73-10080
Patent status: 
Inquiries concerning rights for the commercial use of 
this invention should be addressed to: 
Patent Counsel 
Marshall Space Flight Center 
Code A&PS-PAT 
Marshall Space Flight Center, Alabama 35812 
Source: J. A. Webster of

Monsanto Research Corp.

under contract to

Marshall Space Flight Center

(MFS-22355)
. 
S 
B73-10080	 Category 04	 10


A new intermediate for the production of flexible stable polymers

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server