Second Generation PMR Polyimide/Fiber Composites.
Abstract
A second generation PMR polyimide matrix system (PMR-II) was characterized in both neat resin and composite form with two different graphite fiber reinforcements. Three different formulate molecular weight levels of laboratory prepared PMR-II were examined, in addition to a purchased experimental fully formulated PMR-II precursor solution. Investigations included isothermal aging of graphite fibers, neat resin samples and composite specimens in air at 316c (600F). Humidity exposures at 65C (150F) and 97% relative humidity were conducted for both neat resin and composites for eight day periods. Evaluation of exposed samples included room and elevated temperature testing of composites in flexure and short beam shear and tensile testing of neat resin specimens. Anaerobic char of neat resins and fire testing composites were conducted with PMR-15, PMR-II and an epoxy system. Fire testing of composites was accomplished on a burner right developed for this program. It was found that neat PMR-II resins exhibit excellent isothermal resistance and that PMR-II composite properties appear to be influenced by the thermo-oxidative stability of the reinforcing fiber. Humidity exposures revealed moisture absorption with an accompanying reduction of elevated temperature composite properties. The burner rig provided an inexpensive method for ranking composites for fiber release characteristics and demonstrated the existence of a relation between anaerobic char yield of the matrix and the fiber release behavior of the composites. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 26, 1979
- Accession Number
- ADA078129
Entities
People
- Paul J. Cavano