Accession Number : ADA193313

Title :   Correlations of Norbornenyl Crosslinked Polyimide Resin Structures with Resin Thermo-Oxidative Stability, Resin Glass Transition Temperature and Composite Initial Mechanical Properties.

Descriptive Note : Technical memorandum,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CEN TER

Personal Author(s) : Alston, William B

PDF Url : ADA193313

Report Date : Jan 1988

Pagination or Media Count : 4

Abstract : PMR (polymerization of monomeric reactants) methodology was used to prepare seventy different polyimide oligomeric resins and thirty different unidirectional graphite fiber/polyimide composites. Monomeric composition as well as chain length between sites of crosslinks were varied to examine their effects on resin thermo-oxidative stability and glss transition temperature (Tg) of the cured/postcured resins. A linear correlation of decreasing 316 C resin weight loss/surface area versus (a) decreasing aliphatic content or (b) increasing benzylic/aliphatic stoichiometry ratio over a wide range of resin compositions was observed. An attempt was made to correlate Tg with initial composite mechanical properties (flexural strength and interlaminar shear strength). However, the scatter in mechanical strength data prevented obtaining a clear correlation. Instead, only a range of composite mechanical properties was obtained at 25, 288 and 316 C. Keywords: Glass transition temperature; Composite mechanical properties; Polyimide; Thermo-oxidative stability; Graphite fiber composites.

Descriptors :   *FIBER REINFORCED COMPOSITES, *POLYIMIDE RESINS, *CROSSLINKING(CHEMISTRY), ALIPHATIC COMPOUNDS, CORRELATION, FLEXURAL STRENGTH, GRAPHITED MATERIALS, LAMINAR FLOW, LENGTH, LINEAR SYSTEMS, MECHANICAL PROPERTIES, OXIDATION, POLYMERIZATION, RATIOS, SHEAR STRENGTH, STOICHIOMETRY, STRENGTH(MECHANICS), THERMAL STABILITY, TRANSITION TEMPERATURE

Subject Categories : Polymer Chemistry
      Plastics
      Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE