高等学校化学学报 ›› 2016, Vol. 37 ›› Issue (3): 595.doi: 10.7503/cjcu20150705

• 高分子化学 • 上一篇    下一篇

γ射线辐射诱导聚碳硅烷自由基的衰变

程勇1,2, 李小虎1,2, 刘伟华2, 吴国忠2, 王谋华2   

  1. 1. 上海大学理学院, 上海 200444;
    2. 中国科学院上海应用物理研究所, 上海 201800
  • 收稿日期:2015-09-10 修回日期:2016-01-04 出版日期:2016-03-10 发布日期:2016-01-24
  • 通讯作者: 王谋华,男,博士,副研究员,主要从事高分子材料辐射改性研究.E-mail:wangmouhua@sinap.ac.cn E-mail:wangmouhua@sinap.ac.cn
  • 基金资助:

    中国科学院战略性先导科技专项子课题(批准号:XDA02040300)、国家自然科学基金(批准号:11575279)和上海市自然科学基金(批准号:15ZR1448600)资助.

Decay of Free Radicals in Polycarbosilane Induced by γ-Rays Irradiation

CHENG Yong1,2, LI Xiaohu1,2, LIU Weihua2, WU Guozhong2, WANG Mouhua2   

  1. 1. College of Sciences, Shanghai University, Shanghai 200444, China;
    2. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
  • Received:2015-09-10 Revised:2016-01-04 Online:2016-03-10 Published:2016-01-24
  • Supported by:

    Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA02040300), the National Natural Science Foundation of China(No.11575279) and the Natural Science Foundation of Shanghai, China(No.15ZR1448600).

摘要:

利用电子自旋共振波谱(ESR)研究了在N2气中γ射线辐射诱导聚碳硅烷(PCS)自由基的产生和演变行为. ESR谱图分析结果表明,γ射线辐射诱导PCS产生的自由基为硅自由基(≡Si·).低剂量辐照时硅自由基的浓度随吸收剂量的增加而线性增加,硅自由基的辐射化学产额G值约为9,吸收剂量达到200 kGy后,硅自由基的浓度趋于饱和.室温下硅自由基的浓度随存储时间的延长而逐渐降低,在N2气中存储时硅自由基的半衰期约23 d,在空气中存储时硅自由基的氧化反应导致衰减速率加快,半衰期仅为8 h.温度升高硅自由基衰减速率加快,在N2气中250℃加热处理可以完全清除硅自由基.

关键词: 电子自旋共振, 聚碳硅烷, γ射线辐射, 自由基

Abstract:

The formation and decay behavior of the free radicals trapped in polycarbosilane(PCS) induced by γ-rays irradiation in N2 were investigated by electron spin resonance(ESR). ESR analysis showed that the trapped radicals induced by γ-rays irradiation were assigned to Si radicals(≡Si·). The concentration of free radicals increased with absorbed dose linearly at the lower dose, and the G value of the radical formation was calculated to be 9. However, the concentration of free radicals tends to be saturated when the absorbed dose reached 200 kGy. Upon storage in N2 at ambient temperature the free radicals decayed slowly with a half-life of 23 d. On the contrary, the free radicals decayed rapidly after the sample was exposed to air due to their oxidation, the half-life was only 8 h. The rate of radical decay was accelerated by annealing at elevated temperature, the free radicals trapped in PCS could be removed thoroughly after heating up to 250℃ in N2.

Key words: Electron spin resonance(ESR), Polycarbosilane, γ-Rays irradiation, Free radical

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