Accession Number : AD0834698

Title :   EVALUATION OF HIGH-TEMPERATURE RESINS IN ASBESTOS FIBER REINFORCED LAMINATES

Descriptive Note : Final rept. 1 Sep 1966-1 Oct 1967

Corporate Author : WHITTAKER CORP SAN DIEGO CA NARMCO RESEARCH AND DEVELOPMENT DIV

Personal Author(s) : Smith, Milton B

PDF Url : AD0834698

Report Date : Mar 1968

Pagination or Media Count : 92

Abstract : The work involved an evaluation of the usefulness of epoxy and polyimide in asbestos paper or asbestos mat reinforced laminates. Initially, a crocidolite asbestos mat laminated with a polyimide resin was considered a good candidate, but process optimization studies failed to raise flexural strengths above the 20,000-30,000 psi level. The problem appeared to be one of inadequate wetting of the asbestos fibers, in combination with the excessive volatiles now inherent in the polyimide system itself. Fundamental studies later pointed out the asbestos fibers are very sensitive to buckling, and that voids in the resin matrix cannot be tolerated. Hydroclaving at 30,000 psi was also used in an attempt to alleviate this problem. Eventually, however, it was found that dilute methyl ethyl ketone solutions of epoxy resins - which do not develop volatiles and the consequent voids - provided the best impregnation. Crocidolite and epoxy composites were optimized at about 25 weight percent resin, 2.4 g/cc specific gravity, and 1.5 (or less) volume percent void content. Processing pressures of 1000-5000 psi were required.

Descriptors :   *LAMINATES, ASBESTOS, BUCKLING, COMPRESSIVE PROPERTIES, EPOXY RESINS, FIBERS, FLEXURAL STRENGTH, HIGH TEMPERATURE, KETONES, PERFORMANCE(ENGINEERING), PLASTICS, REINFORCING MATERIALS, STATISTICAL ANALYSIS

Subject Categories : Miscellaneous Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE