Simulation of texture formation processes in carbonaceous mesophase fibres

Abstract

Carbon fibres are spun from carbonaceous mesophases using standard melt spinning techniques. These melt spun carbon fibres exhibit a set of distinct cross-sectional textures. Two widely reported textures in literature are the planar radial (PR) and planar polar (PP). This work uses a mesoscopic model, based on the classical Landau-de Gennes theory of liquid crystals adapted to carbonaceous mesophases, to elucidate the principles that control the texture formation processes. The model is able to capture the microstructure and the formation of the PR and PP textures. A phase diagram for classical PR and PP textures has been constructed in terms of temperature and fibre radius, thus establishing the processing conditions and geometric factors that lead to the selection of these textures. The multipath formation process of the planar polar texture through defect splitting, direct planar polar formation, and defect annihilation has been thoroughly characterized. The results of this work provide new knowledge for optimization and control of mesophase carbon fibre textures.