国产高性能聚丙烯腈基碳纤维制备技术研究进展

Recent progress in high performance PAN based carbon fibers

综述了近年来高性能聚丙烯腈（PAN）基碳纤维的研究进展,对PAN聚合、原丝制备、预氧化和碳化过程中最为关键的问题进行了总结：（1）聚合工艺对共聚单体在PAN分子链上的分布和溶液的均匀性非常重要。与间歇聚合或半连续聚合工艺相比,连续溶液聚合工艺可以提供更稳定的纺丝溶液,减少聚合过程中微凝胶的产生,并提高PAN原丝乃至碳纤维的均匀性。（2）PAN溶液进行湿法或干湿法纺丝过程中,相分离过程控制对PAN原丝及其碳纤维中微缺陷形成和发展,微缺陷的含量至关重要,并最终影响碳纤维的性能。干燥和牵伸工艺对于优化PAN碳纤维原丝的结晶和取向结构,制备高品质的碳纤维原丝同样起决定作用。（3）预氧化的升温速度、最高预氧化温度和预氧化张力控制对预氧丝的皮芯结构、环化指数及其对后续碳化工序的顺利进行产生重要的影响并影响碳纤维的性能;碳化的最高温度影响PAN基碳纤维的强度和模量。（4）碳纤维的结构与其性能具有直接相关性,中国对相关研究仍然比较缺乏,碳纤维生产技术水平和自主创新能力仍然不足。

Recent progresses in the production of high performance polyacrylonitrile（PAN） based carbon fibers are reviewed in this paper,focusing on the polymerization, the production of PAN precursors, the stabilization and carbonization procedures for the production of PAN based carbon fibers. The polymerizing method is the key procedure for the distribution of co-monomers on the PAN line and the homogeneity of the spinning solution. Compared with the bath and semi-continuous polymerizing process, the continuous polymerizing process can produce a homogeneous and stabilizing PAN solution, reducing the formation of PAN microgels, which is beneficial for producing high quality PAN carbon fiber precursors and hereafter the PAN based carbon fibers. The coagulating parameters, as well as the phase separation process of the PAN solutions, determine the formation, the development, and the content of the microvoids in the PAN precursor fibers, which in turn influences the performance of the PAN precursors and thereafter the carbon fibers. The drawing and drying parameters are critical for the optimization of the orientation and the crystallization, as well as the quality of PAN precursor fibers. The heating rate, the highest temperature, and the tensile strength determine the core-shell structure and the cyclization index, which influences the carbonizing process and the properties of the resultant carbon fibers. The strength and the modulus of the carbon fibers are closely related with the temperature and the strength of the carbonizing procedure. The correlation between the structure and the properties of PAN based carbon fibers remains an issue to be further explored, as well as the technology of the production of high performance carbon fibers in China. The combination of fundamental and applied researches are critically needed.