含磷阻燃聚丙烯腈纤维的制备及其性能

为制备含磷无卤阻燃聚丙烯腈纤维，利用KOH水溶液对丙烯腈（AN）-醋酸乙烯酯（VAc）无规共聚物（P（AN-co-VAc））纤维中的VAc单元进行选择性水解，再与O,O-二乙基磷酰氯进行磷酰化反应制得阻燃聚丙烯腈纤维。采用傅里叶变换红外光谱、差示扫描量热和热重分析法对阻燃纤维结构及热性能进行表征，利用扫描电子显微镜对阻燃聚丙烯腈纤维的炭残渣进行分析。结果表明，随水溶液pH值的升高，聚丙烯腈纤维中VAc单元迅速水解；聚丙烯腈纤维中VAc单元的存在使共聚纤维环化放热分解峰值温度增大，当VAc单元的质量分数为30% 时，可达287 ℃，而阻燃聚丙烯腈纤维的该温度高达340 ℃；阻燃聚丙烯腈纤维在800 ℃时的炭残渣量高达48% 以上，远高于共聚合聚丙烯腈纤维41% 的残炭量，具有良好的成炭性。

Preparation and properties of phosphorus-containing flame retardant polyacrylonitrile fiber

In order to prepare halogen-free flame retardant polyacrylonitrile ( PAN ) fibers, the vinyl acetate (VAc) unit in P(AN-co-VAc) fiber was selectively hydrolyzed with KOH aqueous solution at different pH values. The phosphorus-containing flame retardant P( AN-co-VAc) fibers were prepared by the phosphorylation reaction of O, O-diethylphosphoryl chloride with the hydrolyzed P ( AN-co-VAc ) fibers. The structure of P ( AN-co-VAc ) fibers was characterized by Fourier transform infrared spectroscope, and the thermal properties of the fibers were studied by differential scanning calorimetry(DSC) and thermogravimetric analysis( TGA) . The carbon residue of the phosphorus-containing flame retardant P( AN-co-VAc) fiber was analyzed by scanning electron microscope. The results show that the VAc unit is quickly hydrolyzed with the increase of pH. DSC analysis indicat that the presence of VAc increases the temperature of cyclic exothermic peak, and reaches to 287 ℃ with the mass fraction of VAc of 30%, while the temperature of the flame retardant polyacrylonitrile fiber can be up to 340 ℃. TGA demonstrates that the carbon residue of the flame retardant fibers at 800 ℃ is over 48%, which is higher than that of the control fiber ( 41%) , fully proving that the flame retardant P ( AN-co-VAc ) fiber has good carbon forming capability.