Polyimidazopyrrolone polymers, formed by the condensation of aromatic dianhydrides with aromatic tetraamines in various solvents, form moldings that resist degradation in air and retain great strength at 400 to 700 degrees F. The resins have good insulating properties, are easy to mold, and make good protective coatings

Bilow, N.

Landis, A. L.

Miller, L. J.

English

NASA Technical Reports Server

August 1970	 Brief 70-10403 
NASA TECH BRIEF 
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 Clearinghouse for Federal Scientific and Technical 
Information, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
New Hyperthermal Thermosetting Heterocyclic Polymers 
Polyimidazopyrrolone ("pyrrone") polymers, 
formed by the condensation reaction of aromatic 
dianhydrides with aromatic tetraamines in various 
solvents, are excellent thermosetting resins that form 
moldings resisting degradation in air and retaining 
great strength at temperatures between 400° and 700°F. 
Varnishes made from the resins can be used for coat-
ing fabrics or fibers in the manufacture of reinforced 
moldings or laminates. The resins have good insulating 
properties, are easy to mold, and make good protec-
tive coatings. 
One such resin was prepared by addition of 3,3,4,4'- 
benzophenonetetracarboxyiic dianhydride (96.6 g, 
0.3 mole) to 500 ml of hot absolute ethanol. Upon the 
drop-by-drop addition of 20 ml of concentrated sul-
furic acid, the dianhydride dissolved. After the reac-
tion mixture was stirred at reflux for 20 hours, ethanol 
was distilled until the temperature of the mixture rose 
above 100°C. Dissolved in ether, the residue was 
washed several times with water; it was then shaken 
with a 10% solution of sodium bicarbonate until aci-
dification of the bicarbonate washes failed to produce 
a precipitate. After drying over anhydrous magnesium 
sulfate, the ether was evaporated and a product 
weighing 89.3 g (0.19 mole) was collected-63% of the 
theoretical product. 
This product was dissolved in 500 ml of absolute 
ethanol, and 3,3'-diaminobenzicjine (40.5 g, 0.19 mole) 
was added to the refluxing solution. Ethanol was dis-
tilled from the resultant slurry until the temperature 
rose to 150°C at which point the mixture became a 
viscous melt. While being stirred the mixture was
heated further to about 200°C; after 90 min it became 
too viscous for stirring. When cooled the melt-became 
a brittle glass, weighing 108.4 g,.that could be ground 
and used as a molding powder. When dissolved in 
N. N-dimethylacetamide, the partially reacted product 
served as a varnish. Fiberglass laminates had flexural 
strengths exceeding 70,000 lb/in 2 , and moduli exceed-
ing 3 x 10 6
 lb/in 2
 were readily achieved. 
Notes: 
1. The chemical and aircraft industries may be 
interested. 
2. The following documentation may be obtained 
from:
Clearinghouse for Federal Scientific 
and Technical Information 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.65) 
Reference: NASA-CR- 1310 (N69-26448), 
Development and Processing of Pyrrone 
Polymers 
Patent status: 
Inquiries about obtaining rights for the commer- 
cial use of this invention may be made to NASA, 
Code GP, Washington, D.C. 20546. 
Source: N. Bilow, A.L. Landis

and L.J. Miller of

Hughes Aircraft Company

under contract to

Langley Research Center

(LAR-10221) 
Category 04 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
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New hyperthermal thermosetting heterocyclic polymers

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