辐照聚丙烯腈纤维微观结构演变的同步辐射散射研究  

Microstructural evolution of irradiated polyacrylonitrile fibers based on synchrotron radiation scattering

作　　者：黄煜航 邵瑞琪 薛艳玲[2,3] 田丰 李天宇[1] 王维[1] 裴晓园 徐志伟[1] HUANG Yuhang;SHAO Ruiqi;XUE Yanling;TIAN Feng;LI Tianyu;WANG WeiPEI;Xiaoyuan;XU Zhiwei(State Key Laboratory of Separation Membranes and Membrane Processes,School of Textile Science and Engineering,Tiangong University,Tianjin 300387,China;Shanghai Institute of Applied Physics,China Academy of Sciences,Shanghai 201800,China;Shanghai Synchrotron Radiation Facility,Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201204,China)

机构地区：[1]天津工业大学纺织科学与工程学院纺织复合材料教育部重点实验室,天津300387 [2]中国科学院上海应用物理研究所,上海201800 [3]中国科学院上海高等研究院上海同步辐射光源,上海201204

出　　处：《辐射研究与辐射工艺学报》2024年第5期38-45,共8页Journal of Radiation Research and Radiation Processing

基　　金：国家自然科学基金(12205218、52275190)资助。

摘　　要：预氧化是碳纤维制备过程中的关键步骤之一,在此过程中所产生的缺陷大部分将遗传至碳纤维中,所以聚丙烯腈(PAN)预氧化纤维的结构优化对提升碳纤维力学性能尤为重要。辐照是一种优化PAN预氧化纤维结构、有效改善PAN基碳纤维力学性能的改性方法。为探究高剂量电子束辐照PAN纤维在预氧化过程中微观结构的演变,本研究采用了同步辐射原位小角散射(SAXS)、广角散射(WAXS)对高剂量辐照及未辐照PAN纤维热处理过程进行表征,并结合差示扫描量热法(DSC)、热重分析法(TGA)和傅里变换叶红外光谱(FTIR)对PAN预氧化纤维进行表征分析。结果表明:高剂量(500 kGy)辐照促进了PAN纤维在热处理过程中的交联、环化反应,有效缓解了环化反应所引起的剧烈放热,降低了初始环化温度。同时,高剂量辐照对PAN纤维分子结构的破坏作用更加显著,高剂量辐照PAN纤维在热处理后的微孔横向尺寸(D)与取向角(B_(eq))分别降低至7.61 nm和8.58°,晶体层间距d_(002)减小至0.352 nm。综合来说,高剂量辐照使得PAN纤维微观结构在热处理后得到了改善,这有利于改善相应碳纤维的结构和性能。Pre-oxidation is one of the key steps in the preparation of carbon fibers,and most of the defects generated in this process are inherited by the carbon fibers.Therefore,the structural optimization of polyacrylonitrile(PAN)pre-oxidized fibers is particularly important for enhancing the mechanical properties of carbon fibers.Irradiation is a modification method for optimizing the structure of pre-oxidized PAN fibers and effectively improving their mechanical properties.In this study,the microstructural evolution of high-dose electron beam irradiated PAN fibers during the pre-oxidation is investigated.Synchrotron radiation in situ small angle X-ray scattering(SAXS)and wide-angle X-ray scattering(WAXS)were used to characterize the heat treatment process of high-dose irradiated and unirradiated PAN fibers.Additionally,the characterization of PAN pre-oxidized fibers was analytically investigated by combining differential scanning calorimetry(DSC),thermal gravimetric analysis(TGA)and Fourier transform infrared spectroscopy(FTIR).The results showed that high-dose irradiation(500 kGy)promoted the cross-linking and cyclization of the PAN fibers during heat treatment,thus effectively alleviating the intense exotherms caused by the cyclization and reducing the initial cyclization temperature.Additionally,high-dose irradiation significantly affected the molecular structure of the PAN fibers,whereas high-dose irradiation of the PAN fibers during the heat treatment reduced the transverse microporous(D)size,orientation angle(B_(eq)),and crystal-layer spacing d_(002) to 7.61 nm,8.58°,and 0.352 nm,respectively.In summary,high-dose irradiation improves the microstructure of the PAN fibers after heat treatment,which facilitates improvements to the structure and the properties of the corresponding carbon fibers.

关 键 词：高剂量辐照 聚丙烯腈纤维 预氧化 同步辐射 碳纤维 

分 类 号：TL99[核科学技术—核技术及应用]