Structure and Properties of Partially Cyclized Polyacrylonitrile-Based Carbon Fiber-Precursor Fiber Prepared by Melt-Spun With Ionic Liquid as the Medium of Processing

摘要

Carbon fiber has many excellent properties. Currently, the precursor fiber of polyacrylonitrile (PAN)-based carbon fiber is made from solution by wet or dry spinning process that requires expensive solvents and costly solvent recovery. To solve this problem, we developed a meltspun process with ionic liquid as the medium of processing. The melt-spun precursor fiber exhibited partially cyclized structure. The structure and properties of the melt-spun PAN precursor fiber were analyzed by combination of scanning electron microscope, Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, thermogravimetry, ultraviolet spectroscopy, flotation technique, sound velocity orientation test, linear density, and tensile strength tests. The results showed that the tensile strength of melt-spun PAN precursor fiber was fairly high reached up to 7.0 cN/dtex. The reason was the low imperfect morphology and a cyclized structure formed by in situ chemical reaction during melt-spun process. Due to the existence of partially cyclized structure in the melt-spun PAN precursor fiber, exothermic process was mitigated and the heat evolved decreased during thermal stabilization stage in comparison with commercial precursor fibers produced by solution-spun, which could shorten the residence time of thermal stabilization and reduce the cost of final carbon fiber. (C) 2015 Society of Plastics Engineers