Effect of composition of textile grade polyacrylonitrile fiber on preparation of pre-oxidized fiber
Pre-oxidized fibers were prepared using special grade and textile grade polyacrylonitrile(PAN)fibers.The viscosity-average relative molecular mass and composition of different types of PAN precursors were analyzed.The exothermic and pyrolysis processes of textile grade PAN precursors were investigated during pre-oxidation process and compared with that of special grade PAN precursors.The results showed that compared with special grade PAN precursor,the textile grade PAN precursor possessed as low as the viscosity-average relative molecular mass(5-8)×104,and slightly lower breaking strength and the second monomer was mainly vinyl acetate(VAc);the cyclization process of textile grade PAN precursor was milder with VAc as the second mono-mer,and the cyclization degree of the pre-oxidized fiber fiber decreased with the addition of the second monomer;the pre-oxi-dized fiber made from textile grade PAN precursor had a cyclization index of 0.64 and a breaking strength of(2.67±0.22)cN/dtex when VAc was used as the second monomer at a molar fraction of 2.4%,and the PAN precursor can be produced into pre-oxidized fibers at low cost without crosslinking or other pre-treatments.
万方数据
维普
