Application of ductile polymeric coatings onto graphite fibers

Abstract Thin, high molecular weight copolymers have been applied to the surfaces of commercial, 8 micron diameter, graphite fibers by electropolymerization. Random copolymers were obtained, and the process appears to be consistent with the rules of standard free radical copolymerization. Coating thickness, T_g, and modulus can be systematically controlled. Very preliminary mechanical property measurements indicate a substantially improved impact strength and reduction in the interlaminar shear strength. These effects may be related to poor adhesion between the interlayer and the epoxy resin, however, which may be corrected by use of a “top layer” of appropriate composition.