EXPERIMENTAL OBERVATION ON FLOW-INDUCED 'TUMBLING' STRUCTURE OF MOLTEN MESOPHASE PITCH

摘要

The flow induced microstructure of molten mesophase pitch developed during fiber spinning process is of great interests, since the structures of obtained carbon fibers are essentially determined through the process. During the melt spinning process, the rigid aromatic molecules are oriented to align along the fiber axis and are arranged in various ways to impart a spectrum of transverse textures to the precursor fibers[1]. The post-treatments are basically refinements and perfections to the as spun structures[2]. As discotic nematic liquid crystals, mesophase pitches exhibit various liquid crystalline features that had been studied extensively. However, little evidence has been presented for the flow-induced tumbling behavior of mesophase pitches. The objective of this study was to examine the flow behavior (flow-induced tumbling structure) of molten mesophase pitch during the fiber spinning process.