The effect of doping graphene oxide on the structure and property of polyimide-based graphite fibre

Abstract

Herein, graphite fibres were prepared from polyimide (PI) fibres by doping varying contents of graphene oxide (GO) into polyimide (PI) fibres through a carbonization and graphitization process. By in situ polymerization, GO/polyamic acid (PAA) was synthesized and used for preparing GO/PI fibres via dry-jet wet spinning. During the spinning process, the molecular orientation of GO/PI fibres was forced to follow the fibre axis under the strong sheer force at the spinneret. The DSC results show that the exothermic intensity of 1.0 wt% GO/PI composite fibres declined by 69.7% than that of the pure PI fibre; this prevented the breakage of PI molecular chains and maintained the preferred orientation of the GO/PI fibres. During the graphitization process, GO sheets were reduced to grain graphene, acting as nucleus crystals, which could enlarge the size of microcrystals of graphite and increase the degree of graphitization. PI fibres as a carbon precursor showed great potential in the preparation of graphite fibres with high thermal conductivity, and GO doping can improve the thermal conductivity of the composite graphite fibres. When 2.0 wt% GO was added, the thermal conductivity of the GO/PI composite graphite fibre could reach 435 W m⁻¹ K⁻¹, which was twice that of the pure PI-based graphite fibre.