聚丙烯腈原丝预氧化过程中空气压力的作用机理  

Mechanism of Air Pressure in Polyacrylonitrile Precursor Pre-Oxidation Process

作　　者：兰泽铖 周航 王宇 徐樑华[1] Zecheng Lan;Hang Zhou;YuWang;Lianghua Xu(Carbon Fiber and Functional Polymer Key Laboratory of Ministry of Education,School of Materials Science and Engineering,Beijing University of Chemical Technology,Beijing 100029,China)

机构地区：[1]碳纤维及功能高分子教育部重点实验室北京化工大学材料科学与工程学院,北京100029

出　　处：《高分子材料科学与工程》2025年第2期78-86,共9页Polymer Materials Science & Engineering

摘　　要：聚丙烯腈(PAN)纤维在预氧化过程中,环境中氧气向纤维内部扩散的行为会导致纤维径向方向的氧气含量存在差异,使得纤维径向预氧化反应程度不同,形成不均匀的结构,且后续的炭化和石墨化并不能矫正预氧化带来的缺陷,最终影响碳纤维的性能。通过增加环境压力提供氧气向纤维内部扩散的动力,研究了压力对PAN纤维预氧化程度和径向结构的影响,同时提高氧气浓度也会影响氧气在纤维径向的扩散,将不同压力与氧气浓度下制备的预氧纤维进行对比,分析了氧含量改变方式对纤维预氧化行为的影响机制。结果表明,235℃预氧化,热处理时间为20 min时,压力在10~20 kPa范围,纤维的预氧化反应程度从30.65%增加到35.49%,大幅促进了纤维的预氧化反应,同时明显减弱了纤维的皮芯结构。超过20 kPa,压力对纤维预氧化反应和皮芯结构的影响减弱。热处理时间延长到40 min时,压力主要促进纤维环化指数增加,预氧化程度更高。相比于氧气浓度变化,在235℃-20 min等效氧含量下,10 kPa下纤维的预氧化程度(30.65%)大于23%下纤维的预氧化程度(22.80%),压力对纤维预氧化反应程度及径向结构差异影响更大。During the pre-oxidation process of polyacrylonitrile(PAN)fibers,the behaviour of oxygen diffusion from the environment to the interior of the fibers leaded to differences in the oxygen content in the radial direction of the fibers,which resulted in different degrees of pre-oxidation reaction in the radial direction of the fibers and the formation of an inhomogeneous structure,whereas the subsequent carbonation and graphitization can not correct the defects brought about by the pre-oxidation,which ultimately affected the performance of carbon fibers.The effect of pressure on the degree of pre-oxidation and radial structure of PAN fibers was investigated by increasing the ambient pressure to provide the driving force for oxygen diffusion into the interior of the fibers,and at the same time,purely increasing the oxygen concentration also affected the diffusion of oxygen in the radial direction of the fibers,and the pre-oxygenated fibers prepared under the pressure and oxygen concentration were compared to analyze the mechanism of effect of different ways of changing the oxygen content on the pre-oxidation behaviour of the fibers.The results show that the degree of pre-oxidation reaction of the fibers increases from 30.65%to 35.49%when pre-oxidation is performed at 235℃with a heat treatment time of 20 min,and the pressure is in the range of 10~20 kPa,which substantially promotes the pre-oxidation reaction of the fibers,while significantly weakening the skin-core structure of the fibers.Above 20 kPa,the effect of pressure on the pre oxidation reaction and skin-core structure of the fibers is weaken.When the heat treatment time is increased to 40 min,the pressure mainly promotes an increase in the epoxidation index of the fibers and a higher degree of pre oxidation.Compared to the oxygen concentration change,the degree of pre-oxidation of fibers at 10 kPa(30.65%)is greater than that of fibers at 23%(22.80%)at 235℃-20 min equivalent oxygen content,and the pressure has a greater effect on the degree of pre-oxidation

关 键 词：聚丙烯腈预氧纤维 压力 氧气浓度 预氧化程度 径向结构 

分 类 号：TQ342.31[化学工程—化纤工业]