Theory and Simulation of Texture Formation in Mesophase Carbon Fibers

Abstract

ABSTRACTCarbonaceous mesophases are spun into high performance carbon fibers using the melt spinning process. The spinning process produces a range of fiber textures whose origins are not well understood. Planar polar (PP) and planar radial (PR) textures are two ubiquitous ones. A model that describes the formation process of the PP texture based on the Landau-de Gennes mesoscopic theory for discotic liquid crystals, including defect nucleation, defect migration, and overall texture geometry, is presented, solved, and validated. The computed PP and PR textures phase diagram, given in terms of temperature and fiber radius, is presented to establish the processing conditions and geometric factors that lead to the selection of these textures. The influence of elastic anisotropy to the textures formation and structure is also characterized.