Development of an advanced A-type polyimide, which can be used to produce autoclave molded, low-void content composites suitable for use at temperatures up to 316 C is reported. It consists of a mixture of methyl nadic anhydride, an 80:20 molar ratio of methylene dianaline and thiodianilene, and pyromellitic dianhydride

Jones, R. J.

Vaughan, R. W.

English

NASA Technical Reports Server

December 1972
	 B72-10728 
NASA TECH BRIEF S	 Lewis Research 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 KY, Washington, D.C. 20546. 
Low-Void Polyimide Resins for Autoclave Processing 
S
Continuing research on a series of thermally stable 
addition (A)-type polyinude polymers has produced a 
polyinüde resin suitable for autoclave processing, which 
can be used to produce low-void composite materials. 
Fiber reinforced plastic composite materials with high 
level mechanical properties and high temperature service-
ability are destined for many aerospace and other 
industrial applications. The size and configuration of 
such proposed structures require that the composites 
be molded by an autoclave process. 
In NASA Tech Brief 69-10118, a method was 
described for synthesizing thermally stable polyimide 
prepolymers which cured without the release of volatile 
material. Based on this work, an advanced A-type 
polyimide has recently been developed which can be 
used to produce autoclave molded, low-void content 
composites suitable for use at temperatures up to 316°C. 
Glass fiber and high modulus graphite fiber reinforced 
laminates (flat panels) have been successfully fabricated 
in an autoclave process. 
The autoclavable A-type polyimide formulation, call-
ed PlOP-A, consists of a mixture of Methyl Nadic 
Anhydride, an 80:20 molar ratio of methylene dianaline 
and thiodianiline, and pyromellitic dianhydnde at a 
formulated molecular weight of 1000. Glass reinforced 
autoclave composites containing PlOP-A have flexure 
strengths of over 5.5 x 108 N/m2
 (80,000 psi) at 
room temperature with 75% retention at 3160C. Inter-
laminar shear strength retention at 316°C is greater than 
60% and modulus retention is greater than 85%. 
To establish the utility of the new PlOP-A formula-
tion, a demonstration structural component consisting 
of T-sections and curved sections was autoclaved. The
demonstration component had a low void content and 
maintained mold dimensions within 0.2 mm. 
Notes: 
1. The low-void polyimide resin material and auto-
claving process appear to have many useful appli-
cations. While aimed primarily at making autoclaving 
of A-type polyimide resins possible, the new PlOP-A 
polyimide prepolymer can also be fabricated into 
reinforced and unreinforced structures by press mold-
ing or laminating techniques. 
2. The following NASA Tech Briefs describe other Lewis 
Research Center-sponsored work on polyimido poly-
mers:
Tech Brief 69-10118 
Tech Brief 70-10300 
Tech Brief 70.10330 
Tech Brief 70-10504 
Tech Brief 71-10442 
Tech Brief 72-10175 
The following documentation may be obtained from: 
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.95) 
Reference: NASA CR-72984 (N72-18584), 
Thermally Stable Laminating Resins 
4. Technical questions may be directed to: 
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Reference: B72-10728 
S (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=19720000727 2020-03-17T03:44:20+00:00Z
Patent status: 
Inquiries concerning rights for the commercial use of 
this invention should be addressed to: 
Patent Counsel 
Lewis Research Center 
Mail Stop 500-311 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Source: R. J. Jones and R. W. Vaughan of

TRW Systems
under contract to
Lewis Research Center 
(LEW-1 1665)
. 
B72-10728	 Category 04


Low-void polyimide resins for autoclave processing

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