ELECTROCHEMICAL PROCESS FOR PREPARING CONTINUOUS GRAPHITE FIBER THERMOPLASTIC COMPOSITES

An electrochemical process for preparing thermoplastic matrix-graphite fibre composites has been developed. Graphite fibre poly(maleimide-co-styrene) matrix composites were prepared using unsized AS-4 graphite fibre preforms as the working electrode. Copolymers of a wide range of N-substituted maleimides and styrene were formed directly on the surface of the graphite fibres. The rate of electrocopolymerization varied with the electrocopolymerization parameters, such as the comonomer concentration, current density, supporting electrolyte concentration, electropolymerization time, nature of the solvent, solvent/dilute sulfuric acid ratio and the structure of the maleimide. Graphite fibre preforms preimpregnated with the electropolymerized thermoplastic matrices were processed into unidirectional composite laminates. The electrosynthesized thermoplastic matrix composites showed excellent physical and mechanical properties.