论文部分内容阅读
本文通过核磁氢谱、DSC和分子量测定,研究了结晶对等规立构聚甲基丙烯酸甲酯辐射消旋和辐射裂解的影响.分子量测定的结果表明,等规立构聚甲基丙烯酸甲酯结晶后,其辐射裂解反应减弱,裂解G值减小将近一半.核磁氢谱测定辐照试样的空间立构变化结果为:随着辐照剂量的增加,等规立构逐渐变为无规立构和间规立构,其变化规律相似于非晶试样.结果还表明,晶区的消旋反应比裂解反应更为显著.DSC测得的试样熔点,随着辐照剂量的增加而急剧下降,由Flory结晶熔化理论计算得晶区的辐射破坏G值为8.8.该值远大于聚乙烯晶区的破坏G值.
In this paper, the effects of crystallization on isotactic polymethylmethacrylate radiation and radiation cleavage were studied by 1H-NMR, DSC and molecular weight determination.The results of molecular weight determination showed that isotactic polymethylmethacrylate After the crystallization, the radiation pyrolysis reaction is weakened and the G value of pyrolysis is reduced by nearly half.The spatial stereospecific changes of the irradiated samples by 1H NMR spectroscopy are as follows: the isotactic structure gradually becomes random with the increase of irradiation dose The results showed that the racemization reaction was more pronounced than that of the cleavage reaction.The melting point of the sample measured by DSC increased with the increase of irradiation dose But dropped sharply, and the value of the radiation damage G of the crystal region calculated by the Flory crystal melting theory was 8.8, which is much larger than that of the polyethylene crystal region.