A graphene/graphite-based conductive polyamide 12 interlayer for increasing the fracture toughness and conductivity of carbon-fiber composites

Abstract

A conductive thermoplastic material was developed to increase the interlaminar fracture toughness and through-the-thickness conductivity of carbon-fiber-reinforced plastics materials. A polyamide 12 nonwoven fabric was coated with graphene/graphite particles in a solution of hexane, water, and graphite particles. The graphite powders were exfoliated in the sonication bath and the resulting layers of graphene resided at the interface of the immiscible solvents, where the graphene layers/graphite simultaneously infused into the polyamide 12. The sonication time and graphite content were optimized to maximize the surface conductivity of conductive polyamide 12 fabric. The presence of pristine graphene flakes and graphite on the polyamide 12 fabric was confirmed by X-ray diffraction and scanning electron microscopy. The dry fabric preform was interleaved with the conductive polyamide 12 and the composite laminates were manufactured by a vacuum-assisted resin transfer molding process. The resulting composite laminate resulted in a significant increase in Mode I and Mode II fracture toughness up to 42% and 141%, respectively, and a decrease in the volume resistivity from 100 MΩm to 402 Ωm.