同步X射线散射技术研究变温及拉伸后聚四氟乙烯的微观结构变化  

Analysis of microstructural deformation in polytetrafluoroethylene under heating or stretching conditions by synchrotron X-ray scattering

作　　者：沙飞翔 程国君[1] 田丰[2,3] 唐忠锋[2] SHA Feixiang;CHENG Guojun;TIAN Feng;TANG Zhongfeng(College of Material Science and Engineering,Anhui University of Science&Technology,Huainan 232001,China;Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201210,China)

机构地区：[1]安徽理工大学材料科学与工程学院,淮南232001 [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201210

出　　处：《辐射研究与辐射工艺学报》2022年第3期15-22,共8页Journal of Radiation Research and Radiation Processing

基　　金：国家重点研发计划(2019YFF0302201);哈尔滨工业大学空间环境材料行为及评价技术国防科技重点实验室项目(6142910190203)资助。

摘　　要：聚四氟乙烯(PTFE)在变温及拉伸下的微观结构变化研究,对于其服役过程中的失效机制分析具有重要意义。本文采用同步X射线散射技术原位在线研究PTFE在变温处理(25~300℃)以及常温和变温(25~175℃)单轴拉伸下的微观结构变化。结果表明:PTFE的散射强度随温度而增加,不完全晶体逐渐熔融;常温单轴拉伸PTFE在低应变下分子链发生倾斜,片晶沿拉伸方向滑移和转动;在恒定应力的单轴拉伸过程中,随温度升高,PTFE中不完全晶体逐渐熔融,受应力作用片晶被破坏,在其发生α转变之后,其片晶由于非晶部分分子链运动的解冻而被进一步破坏。The analysis of microstructure deformation in polytetrafluoroethylene(PTFE) under heating or stretching conditions is essential to determine the failure mechanism. This study employed the synchrotron X-ray scattering technique to study microstructural deformation in PTFE under heating(25~300 ℃), different strains at room temperature, and constant stress at variable temperatures(25~175 ℃). The results indicate that the scattering the scattering intensity of PTFE increases with an increase in the temperature, and the imperfect crystals gradually melt. When PTFE was stretched under relatively lower strains at room temperature, its molecular chains tilted and lamellar crystals slid and rotated along the stretching direction. Moreover, when PTFE was stretched at constant stress and varying temperatures, its imperfect crystals gradually melted with an increase in the temperature and lamellar crystals were fractured by stress;the crystals were further fractured owing to the α-transition temperature caused by the movement of molecular chains in the amorphous regions.

关 键 词：聚四氟乙烯 微观结构 同步辐射 X射线小角散射 超小角X射线散射 

分 类 号：O434[机械工程—光学工程]