热亚胺化中应力对聚酰亚胺纤维结构和性能的影响  

Influences of stress in thermal imidization on structure andproperties of polyimide fibers

作　　者：王彪[1,2] 李源 董杰[1,2] 张清华[1,2] WANG Biao;LI Yuan;DONG Jie;ZHANG Qinghua(College of Materials Science and Engineering,Donghua University,Shanghai 201620,China;State Key Laboratory of Modification of Chemical Fibers and Polymer Materials,Donghua University,Shanghai 201620,China)

机构地区：[1]东华大学材料科学与工程学院,上海201620 [2]东华大学纤维材料改性国家重点实验室,上海201620

出　　处：《纺织学报》2025年第3期1-8,共8页Journal of Textile Research

基　　金：国家自然科学基金项目(52373318);国家重点研发计划项目(2023YFB3811901)。

摘　　要：为提高聚酰亚胺(PI)前驱体环化纤维的力学性能,并优化其微结构,通过红外光谱、X射线衍射、力学性能及热稳定性测试,研究了在热亚胺化过程中施加一定应力对PI纤维结构和性能的影响。结果表明:施加应力加快了热亚胺化反应的进程,300℃保温120 s,纤维亚胺化程度达到90%,相比于松弛状态下提升了17%,这有利于纤维性能的提升;在纤维聚集态结构方面,应力作用下,纤维轴向晶面间距增大,取向度和结晶度提高;相较于松弛状态下,经400℃应力热亚胺化反应,纤维内部(004)晶面的取向度由0.63提升至0.80,结晶度由14.20%提升至16.73%,表明纤维内部形成更加完善的晶体结构,纤维径向分子链有序度增加,但大部分仍为非晶结构;得益于热亚胺化过程中分子链取向度的提高,纤维的强度和模量显著提升,断裂伸长率下降,且在应力作用下,经400℃热亚胺化处理纤维的5%和10%热失重温度分别达到529℃和565℃。Objective The mechanical properties of high-performance polymer fibers such as Kevlar(poly(p-phenylene-terephthamide)(PPTA)fiber)and Zylon(poly(p-phenylenebenzobis-oxazole)(PBO)fiber)can deteriorate severely when exposed under an UV irradiation condition.Polyimide(PI)fiber is of great interest to researchers with excellent irradiation resistance,high thermal stability and good mechanical property.Generally,the preparation of PI fiber adopts a two-step process,i.e.,fabrication of polyamic acid(PAA)fibers,and then the conversion of PAA fibers into PI fibers by a thermal imidization process which is one of the key processes affecting the microstructure and the overall properties of resultant PI fibers.This research investigates the thermal imidization process aiming to prepare high performance PI fibers.Method The precursor PAA fibers were fabricated through a dry-jet wet spinning process(a classic two-step method).The PI fibers were prepared by thermal imidization of PAA fibers under a relaxation state and satress state,respectively.The evolution of chemical structure and aggregation structure of PI fibers under different states were compared and analyzed using Fourier transform infrared spectroscopy,wide-angle X-ray diffraction,thermogravimetric analysis and so on.The relationship between the structure and properties of PI fibers was established.Results The thermal imidization process was accelerated by the applied stress.The degree of imidization of fibers reached 90%at 300℃for 120 s under a stress of 30 cN,which was 17%higher than that in the relaxation state,thus contributing to the enhancement of fibers′properties.Under a stress,the axial crystal plane spacing of fibers increased after thermal imidization,leading to an increase in orientation and crystallinity of the fiber.Compared to the relaxation state imidization,the orientation degree of the(004)plane increased from 0.63 to 0.80,and crystallinity increased from 14.20%to 16.73%after the stress-state thermal imidization,indicating a more perfect crystal

关 键 词：高性能纤维 聚酰亚胺纤维 干喷湿纺 热亚胺化 应力 聚集态结构 

分 类 号：TB383[一般工业技术—材料科学与工程]