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

doi:10.7503/cjcu20150705

Abstract

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

CLC Number:

TrendMD:

CHENG Yong, LI Xiaohu, LIU Weihua, WU Guozhong, WANG Mouhua. Decay of Free Radicals in Polycarbosilane Induced by γ-Rays Irradiation[J]. Chem. J. Chinese Universities, 2016, 37(3): 595.

References

[1] Lee J. S., Yano T., Journal of the European Ceramic Society, 2004, 24(1), 25-31
[2] Idesaki A., Narisawa M., Okamura K., Sugimoto M., Morita Y., Seguchi T., Itoh M., Radiation Physics and Chemistry, 2001, 60(4/5), 483-487
[3] Xue J. G., Wang Y. D., Song Y. C., Qin M. L., Acta Polymerica Sinica, 2007, 1(3), 219-222(薛金根, 王应德, 宋永才, 秦墨林. 高分子学报, 2007, 1(3), 219-222)
[4] Bouillon E., Langlais F., Pailler R.,Naslain R., Cruege F., Huong P. V., Sarthou J. C., Delpuech A., Laffon C., Lagarde P., Monthioux M., Oberin A., J. Mater. Sci., 1991, 26(5), 1333-1345
[5] Song M. L., Tech. Ceramics in Jingdezhen International Forum, Jingdezhen, 2006(宋麦丽, 景德镇:景德镇国际论坛之制陶技术, 2006)
[6] Xie Z. F., Chen C. H., Xiao J. Y., Hu H. F., Zheng W. F., Polymer Materials Science and Engineering, 2000, 16(6), 7-12(谢征芳, 陈朝辉, 肖加余, 胡海峰, 郑文伟. 高分子材料科学与工程, 2000, 16(6), 7-12)
[7] Chen C. H., Polymer-derived Ceramic Matrix Composites, Science Press, Beijing, 2012(陈朝辉. 先驱体转化陶瓷基复合材料, 北京:科学出版社, 2012)
[8] Xiong L. P., Xu Y. S., Progress in Chemistry, 2007, 19(4), 567-574(熊亮萍, 许云书. 化学进展, 2007, 19(4), 567-574)
[9] Xu Y. S., Materials for Mechanical Engineering, 2012, 36(1), 1-6(许云书. 机械工程材料, 2012, 36(1), 1-6)
[10] Chen Y. L., Zeng Z. H., Yang J. W., Radiation Curing Materials and Applications, Chemical Industry Press, Beijing, 2003(陈用烈, 曾兆华, 杨建文. 辐射固化材料及其应用, 北京:化学工业出版社, 2003)
[11] Okamura K., Seguchi T., Journal of Inorganic and Organometallic Polymers, 1992, 2(1), 171-179
[12] Li Y., Xu Y. S., Journal of Nuclear and Radiochemistry, 2009, 31(2), 104-108(黎阳, 许云书. 核化学与放射化学, 2009, 31(2), 104-108)
[13] Ye Z. W., Wang M. H., Wu G. Z., New Chemical Materials, 2014, 42(3), 60-62+65(叶泽文, 王谋华, 吴国忠. 化工新型材料, 2014, 42(3), 60-62+65)
[14] Wang B., Du L. B., Liu Y. P., Zhou J. W., Liu Y., Chem. J. Chinese Universities, 2014, 35(11), 2366-2369(王兵, 杜立波, 刘阳平, 周建威, 刘扬. 高等学校化学学报, 2014, 35(11), 2366-2369)
[15] Mao Y. G., Wang G. B., Zheng Y. G., Shen J. C., Chem. J. Chinese Universities, 1993, 14(6), 879-882(毛友钢, 王国试, 郑莹光, 沈家骢. 高等学校化学学报, 1993, 14(6), 879-882)
[16] Xu Y. Z., Practical Electronic Magnetic Resonance Spectroscopy, Science Press, Beijing, 2008, 91-99(徐元植, 实用电子磁共振波谱学, 北京:科学出版社, 2008, 91-99)
[17] Chu S. L., Atomic Physics, Higher Education Press, Beijing, 1979, 180-184(褚圣麟, 原子物理学, 北京:高等教育出版社, 1979, 180-184)
[18] Belogolova E. F., Vakul'skaya T. I., Sidorkin V. F., Phys. Chem. Chem. Phys., 2015, 17(9), 12735-12746
[19] Lü J. H., Wu K., Ma J. T., Yao K. D., Chem. J. Chinese Universities, 1990, 11(1), 66-70(吕俊怀, 吴可, 马季涛, 姚康德. 高等学校化学学报, 1990, 11(1), 66-70)
[20] Liu W. H., Wang M. H., Xing Z., Wu G. Z., Radiation Physics and Chemistry, 2012, 81(7), 835-839
[21] Oshima A., Seguchi T., Tabata Y., Radiat. Phys. Chem., 1997, 50(6), 601-606
[22] Seguchi T., Tamura N., J. Phys. Chem., 1973, 77(1), 40-44
[23] Qi Y. N., Wang M. H., Song Y. C., Wu G. Z., New Chemical Materials, 2011, 39(10), 85-87(戚英娜, 王谋华, 宋永才, 吴国忠. 化工新型材料, 2011, 39(10), 85-87)
[24] Mishra R., Tiwari R. K., Saxena A. K., J. Inorg. Organomet Polym., 2009, 19(2), 223-227
[25] Liu Q., Wu H. J., Lewis R., Maciel G. E., Interrante L. V., Chem. Mater., 1999, 11(8), 2038-2048