Mechanical properties of carbon fibre/PMR-15 composites containing thermoplastic polyimide interphase coatings

Abstract

Thermoplastic copolyimide synthesised from 3,3′, 4,4′-benzophenonetetracarboxylic dianhydride, 4,4′-oxydianiline, and 1,3-phenylenediamine were success fully coated onto carbon fibres by electrochemical deposition and subsequently impregnated with polymerisable reaction mixtures of PMR-15 thermosetting polyimide. Carbon fibre/PMR-15 composites containing the thermoplastic interphase coatings showed higher flexural strength, flexural modulus, and impact strength than control carbon fibre/PMR-15 composites containing no thermoplastic interphase. The flexural properties of the composites increased with increasing interphase thickness, however impact strength decreased with increasing thickness of the thermoplastic polyimide interphase.