硅系油剂对PAN纤维预氧化的影响

改变聚丙烯腈(PAN)纤维纺丝工艺,制得无油纤维和含油纤维,在空气气氛下对两种纤维进行预氧化处理。借助体密度、差示扫描量热仪(DSC)、傅里叶变换红外光谱仪(FT-IR)和X射线衍射仪(XRD)等测试手段,通过表征PAN纤维的预氧化程度,揭示硅系油剂的作用。结果表明,硅系油剂在190℃～250℃温度区间,即本论文讨论的预氧化反应全程,不发生化学反应,依然均匀涂覆在PAN纤维的表面;在预氧化反应的前期(190℃～220℃),纤维表面的油剂阻碍热的传递和氧的扩散,使得含油纤维的体密度、环化度、相对环化率和芳构化指数均低于无油纤维;在预氧化后期(220℃～250℃),由于前期油剂对预氧化反应的抑制,使得前期形成的结构有利于氧的扩散,表象上硅系油剂在预氧化后期起着促进的作用。

Effect of Silicone Oil on Pre-oxidation of PAN Fibers

Polyacrylonitrile(PAN) fibers with and without silicone oil were prepared and pre-oxidized at different temperatures in air.The degree of pre-oxidation of PAN fibers was determined by bulk density measurements,differential scanning calorimetry(DSC),Fourier transform infrared(FT-IR) spectroscopy,and X-ray diffractometry(XRD).It was concluded that silicone oil did not undergo chemical reaction during the pre-oxidation process(190-250℃).During the prophase of pre-oxidation(190-220℃),silicone oil on the surface of the fibers inhibited heat transfer and diffusion of oxygen,so the bulk density,cyclization index(CI),relative cyclization index(RCI) and aromatization index(AI) of the fibers with silicone oil were less than those of the fibers without oil.During the anaphase(220-250℃),due to the restriction by the silicone oil of pre-oxidation,the structures formed in the prophase were beneficial to diffusion of oxygen.Thus silicone oil evidently played a promoting role in the anaphase of pre-oxidation.