【作者】 杨俊； 毛友钢； 华士英； 沈家骢； 董凤霞； 郑莹光；

【Author】 Jun Yang Yougang Mao Shiying Hua Jiacong Shen (Key Laboratory for Supramoecular and Spectrocopy,J(?)lin University,Changchun,130023) Fengxia Dong Yingguang Zheng (Analytical Measurement Center,Jilin University,Changchun,130023)

【机构】 吉林大学超分子结构和谱学开放实验室理论化学研究所； 吉林大学分析测试实验中心；

【摘要】 <正>甲基丙烯酸甲酯(MMA)本体聚合反应全程的增长自由基的 ESR 谱的从 13线到9线的线宽和强度的变化是一个复杂的问题,其复杂性表现在增长自由基所处的环境随着反应的进行经历从溶液态到凝胶态和固态的变化,而环境的变化对增长自由基的 ESR 谱有很大的影响。根据我们聚合反应动力学的实验结果和前人所作的工作,我们将聚合反应全程的 ESR 谱分为两个阶段：更多还原

【Abstract】 Change in linewide and intensity of methyl methacrylate(MMA)radical spectra from 13 lines to 9 lines in whole polymerization process is complex because environment of radical which obviously influences ESR spectra changes from solution state to gel state and glass state.We divide whole process into two stages which are before and after gel effect because polymerization is in solution state before gel effect and in gel or glass state after it.We think that increment of inner 8 lines intensity is caused by the hindered osillation between two stable conformations which are mirror images of each other.But after gel effect,environment of radical is solid,speed of hindered osillation is so slow that it is not measured by ESR spectrometer because it is beyond the time scale of ESR.On basis of hindered osillation model and gaussion distribution medel,we made a dynamical simulation program and gaussion distribution program by TurboC2,and simulated spectra satisfactorily agreeed with spectra from experiment and obtained some microcosic structural factor.These factor indicate change of environment of radicals.At beginning stage of polymerization,the most probable conformation angle gained from simulation is eaqual to result of conformation energy calculation,this show that environment of radical is in state of thermal-balance.In auto-acceleration process,the most probable conformation angle slightly deviate the one from the calculation and interchange speed between two stable conformation become faster,this shows that the environment of radical is no longer in thermal-balance state,this state is caused by relay of chain relaxation when several thousands of chains propagate at a moment.更多还原