The use of gel spinning technology in the formation of polyacrylonitrile (PAN)-based carbon fibers has led to significant tensile property improvements. PAN, dimethylsulfoxide (DMSO) and dimethylformamide (DMF) solutions were dry-jet spun, gelled in methanol at −20 and −50 °C for different times from 0 to 40 d, and vacuum-dried at 0 °C for 24 h to obtain PAN fibers that were drawn to a drawing ratio (DR) of 4 in a hot glycerin bath at 110 °C, and then to various DRs in a glycerin bath at 155 °C. The effects of gelation time on the microstructures, mechanical properties and cyclization reactions of the gel-spun PAN fibers were investigated. Results showed that the gelation time affected the gel structure and the maximum possible draw ratio. The gelation effects were significant in the first 5-10 d, and were more prominent for the DMSO system than the DMF system. The maximum possible draw ratio, strength and modulus, orientation and crystallinity of the PAN fibers increased with gelation time. The cyclization temperature decreased and the reaction enthalpy increased with gelation time in cyclization, indicating an improved chain orientation and crystallinity with gelation time. Gelation was an important step affecting the microstructures and properties of gel-spun PAN fibers for making high performance carbon fibers.

在聚丙烯腈（PAN）基碳纤维的形成过程中使用凝胶纺丝技术已导致拉伸性能的显着改善。将PAN，二甲基亚砜（DMSO）和二甲基甲酰胺（DMF）溶液干喷纺丝，在-20和-50°C的甲醇中凝胶化0至40 d，然后在0°C真空干燥24 h至获得在110°C的甘油热浴中拉伸至拉伸比（DR）为4，然后在155°C的甘油浴中拉伸至各种DR的PAN纤维。研究了凝胶时间对凝胶纺PAN纤维微观结构，力学性能和环化反应的影响。结果表明，胶凝时间影响凝胶结构和最大可能的拉伸比。在头5到10天，胶凝作用显着，在DMSO系统中比在DMF系统中更为突出。PAN纤维的最大可能拉伸比，强度和模量，取向和结晶度随胶凝时间而增加。环化反应中，随着胶凝时间的延长，环化温度降低，反应焓增加，表明随着胶凝时间的延长，链取向和结晶度提高。胶凝化是影响用于制造高性能碳纤维的凝胶纺PAN纤维的微观结构和性能的重要步骤。表明随着胶凝时间的改善链取向和结晶度。胶凝化是影响用于制造高性能碳纤维的凝胶纺PAN纤维的微观结构和性能的重要步骤。表明随着胶凝时间的改善链取向和结晶度。胶凝化是影响用于制造高性能碳纤维的凝胶纺PAN纤维的微观结构和性能的重要步骤。