PHTHALONITRILE-GLASS FABRIC COMPOSITES

Phthalonitrile polymers, under development at the Naval Research Labor atory, offer promise as high temperature, high performance composite m atrix materials. A fully cured resin shows outstanding thermal stabili ty with no evidence of a glass transition temperature or T-g up to 450 degrees C, good mechanical properties, and fs easily processed into v oid-free components. Phthalonitrile/glass fabric composite panels have been successfully fabricated by conventional consolidation of prepreg ged glass and by a more recently developed simplified process, resin i nfusion molding. Both processes can be used to produce panels with com parable mechanical properties. More important, flammability performanc e of these composites, evaluated In terms of specific optical density, combustion gases, heat release, and ignitability, excels over other s tate-of-the-art polymer/glass composites. This finding is significant given that overcoming flammability obstacles has been the main limitin g factor for use of composites in marine applications.