Free-radical evolution and decay in cross-linked polytetrafluoroethylene irradiated by gamma-rays  

作　　者：Fei-Xiang Sha Guo-Jun Cheng Zi-Yue Xuan Yang Liu Wei-Hua Liu Xiao-Dong Zhang Zhong-Feng Tang 

机构地区：[1]School of Materials Science and Engineering,Anhui University of Science and Technology,Huainan 232000,China [2]Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China [3]National Key Laboratory of Materials Behavior and Evaluation Technology in Space Environment,Harbin Institute of Technology,Harbin 150001,China [4]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Nuclear Science and Techniques》2022年第5期113-125,共13页核技术（英文）

基　　金：supported by the Fund for Strengthening Technical Fields of Basic Plan(No.2021-JCJQ-JJ-0128);National Key R&D Program of China(No.2019YFF0302201);the National Key Laboratory of Materials Behavior and Evaluation Technology in the Space Environment Harbin Institute of Technology(No.6142910190203)。

摘　　要：Electron spin resonance techniques were employed to investigate the effects of the absorbed dose and post-irradiation conditions on the evolution and decay of free-radicals in cross-linked polytetrafluoroethylene(XPTFE),induced byγ-ray radiation.Chain-end free-radicals,chain alkyl free-radicals,and tertiary alkyl free-radicals were detected when XPTFE was irradiated under Ar atmosphere.The corresponding peroxy free-radicals were formed upon exposure of irradiated XPTFE to air;the freeradicals concentration first increased linearly with increasing absorbed dose and then gradually saturated.The free-radicals yield under air atmosphere was greater than that under Ar,and the peroxy free-radicals were preserved for a relatively long time when irradiated XPTFE was stored under air atmosphere.The chain alkyl free-radicals may be converted to chain end free-radicals byβ-scission,while chain end free-radicals are more sensitive to oxygen than chain alkyl free-radicals.When the annealing temperature was raised above the a-transition temperature of XPTFE,the decay of the free-radicals was greatly affected and accelerated by the motion of the molecules over the long range.

关 键 词：Polytetrafluoroethylene Cross-linked polytetrafluoroethylene Electron spinresonance DECAY Radiation c-ray 

分 类 号：TQ325.4[化学工程—合成树脂塑料工业]