聚丙烯腈纤维预氧化过程结构演变及与碳纤维结构比较  

Structural Evolution of Polyacrylonitrile Fibers During Pre-oxidation and Comparison with Carbon Fiber Structure

作　　者：华夏 崔野 郭万元 史颖 刘立志 宋立新[1,2] Hua Xia;Cui Ye;Guo Wanyuan;Shi Ying;Liu Lizhi;Song Lixin(Advanced Manufacturing Institute of Polymer Industry,Shenyang University of Chemical Technology,Shenyang 110142,China;Shenyang Advanced Coating Material Industry Technology Research Institute Co.,Ltd.,Shenyang 110326,China)

机构地区：[1]沈阳化工大学高分子产业高端制造研究院,沈阳110142 [2]沈阳先进涂层材料产业技术研究院有限公司,沈阳110326

出　　处：《工程塑料应用》2021年第6期125-130,共6页Engineering Plastics Application

基　　金：辽宁省攀登学者项目;辽宁省教育厅青年科技人才项目(LQ2020007)。

摘　　要：聚丙烯腈(PAN)在预氧化过程中取向度、晶体结构和微孔结构的变化直接影响碳纤维的性能。通过模拟连续产线上保持牵引张力的PAN原丝的预氧化过程,研究阶梯升温的预氧化过程中纤维取向度、晶体结构和微孔结构的变化。结果表明,通过保持张力可以使PAN大分子链发生环化反应的温度升高,预氧化前期(240℃以下),PAN原丝较好地保持了晶体结构和取向,纤维内微孔呈尖细形态,并沿着纤维轴方向取向;预氧化后期(270℃),PAN晶体熔融和分子链转化成梯形结构同时发生,使纤维在晶体熔化的同时保持了较好的取向。预氧化处理后的纤维微孔长径比有所下降,受解取向影响,微孔形态略微变圆,但微孔取向有所提高,纤维整体保持了较好的取向度。通过预氧化过程,使纤维在进一步高温碳化中能够保持良好的取向,使得到的碳纤维具有较高的力学性能。因此,预氧化过程高温阶段的取向调控是得到高性能碳纤维的重要因素。The changes in orientation,crystal structure and void structure of polyacrylonitrile(PAN)during the pre-oxidation process directly affect the performance of carbon fibers.By simulating the pre-oxidation process of PAN precursor yarns that maintain traction tension on a continuous production line,the changes in fiber orientation,crystal structure and void structure during the pre-oxidation process with stepped heating were studied.The results show that by maintaining tension,the temperature of the cyclization reaction of PAN macromolecular chains can be increased.In the early stage of pre-oxidation(below 240℃),the PAN precursor better maintains the crystal structure and orientation,and the voids in the fiber are pointed.In the late stage of pre-oxidation(270℃),the melting of PAN crystals and the transformation of molecular chains into trapezoidal structures occur simultaneously,so that the fibers maintain a good orientation while the crystals are melted.After the pre-oxidation treatment,the fiber void length-to-diameter ratio decreases.Affected by the de-orientation,the void morphology become slightly rounded,but the void orientation increases,and the fiber maintains a good degree of orientation.Through the pre-oxidation process,the fiber can maintain good orientation during further high-temperature carbonization,so that the obtained carbon fiber has higher mechanical properties.Therefore,the adjustment of the orientation in the high-temperature stage of the pre-oxidation process is an important factor for obtaining high-performance carbon fibers.

关 键 词：聚丙烯腈纤维 碳纤维 预氧化 晶体取向 微孔结构 

分 类 号：TQ342.31[化学工程—化纤工业]