Accession Number : ADA305868

Title :   Development of Pyrrone Structural Foams For Honeycomb Filler.

Corporate Author : HUGHES AIRCRAFT CO CULVER CITY CA

Personal Author(s) : Kimmel, B. G.

PDF Url : ADA305868

Report Date : MAR 1973

Pagination or Media Count : 45

Abstract : The development of techniques for the preparation of pyrrone structural foams for use as honeycomb filler is described. The feasibility of preparing foams from polymers formed by the condensation of 3,3'-diaminobenzidine (DAB), or 3,3' ,4,4'-tetraaminobenzophenone (TABP), with 3,3' ,4,4'-benzophenone tetracarboxylic dianhydride (BTDA) was investigated. Initially, most of the effort was devoted to preparing pyrrone prepolymers with improved and more reproducible foaming properties for making chemically blown foams. When it became apparent that very high curing shrinkages would not allow the use of unfilled pyrrone prepolymers in a 'foam-in-place' process, emphasis was shifted from chemically blown foams to syntactic foams. Syntactic foam formulations containing hollow carbon microspheres were developed. Syntactic foams made from selected formulations were found to have very low coefficients of thermal expansion. A technique was developed for the emplacement of pyrrone syntactic foam formulations in honeycomb core structures.

Descriptors :   *HONEYCOMB CORES, *FILLERS, *SYNTACTIC FOAMS, POLYMERS, FORMULATIONS, CARBON, COEFFICIENTS, THERMAL EXPANSION, CURING, REPRODUCIBILITY, MICROSPHERES.

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE