高性能聚丙烯腈(PAN)碳纤维原丝中二甲基亚砜(DMSO)溶剂含量是产品质量控制的重要指标,沸水状态下提取可能造成DMSO分解,影响纤维中残留DMSO含量准确测定。采用液相色谱质谱联用研究了DMSO在100℃的热分解反应,发现有二甲基二硫醚或二甲基砜产生,表明沸水不适合作为PAN纤维中DMSO的提取剂;采用紫外分光光度计研究了DMSO在不同有机溶剂中的紫外吸收,其在环己烷、丙酮和乙醇的紫外吸收灵敏性依次降低,但比水更灵敏;湿法纺丝工艺制备了PAN水洗纤维,采用动态接触角测定仪研究了不同有机溶剂与PAN水洗纤维的接触角,发现溶剂与PAN纤维接触角大小与溶剂极性相关,有机溶剂的接触角更小,表明有机溶剂更易浸润纤维。分析DMSO在有机溶剂的紫外吸收灵敏性和有机溶剂与PAN纤维浸润性,表明环己烷、丙酮和乙醇作为PAN纤维残留溶剂二甲基亚砜的提取剂具有可行性。

Dimethyl sulfoxide (DMSO) solvent content in high performance polyacrylonitrile (PAN) carbon fiber precursor was an important index for product quality control.DMSO might be decomposed during extraction from PAN fiber in boiling water that would affect the accurate determination of residual DMSO content in PAN fiber.The thermal decomposition of DMSO at 100℃ was studied by LC-MS.It is found that dimethyl disulfide or dimethyl sulfone were produced,which indicated that boiling water was not suitable for extracting DMSO from PAN fiber.The UV absorption of DMSO in different organic solvents was studied by UV spectrophotometer.The UV sensitivity of DMSO in cyclohexane,acetone and ethanol decrease in turn,but they were more sensitive than water.PAN fiber was prepared by wet spinning process.The contact angle between different organic solvents and PAN fiber was studied by dynamic contact angle tester.The contact angle between solvent and PAN fiber was related to solvent polarity,and the contact angle of organic solvent with PAN fiber was smaller,which indicated that organic solvent was easier to infiltrate the fiber.The UV absorption sensitivity of DMSO in organic solvents and the wettability between organic solvents and PAN fibers were analyzed.The results shown that cyclohexane,acetone and ethanol were feasible as solvent extractants for DMSO residues in PAN fiber.