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

Thermoplastic copolyimide synthesised front 3,3: 4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydianiline, and I,3-phenylenediamine were successfully 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.