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以全同立构聚甲基丙烯酸甲酯(iso-PMMA)为对象,用核磁共振谱和分子量测定等手段,研究了不同物理状态,即无定型固态,结晶态和稀溶液状态下的辐射裂解和辐射消旋反应.结果表明,在稀溶液状态下辐照,其裂解反应最强,而消旋反应最弱;结晶状态下辐照,则裂解反应最弱而消旋反应最强.这充分说明了分子的活动性对反应的影响,进一步验证了前已提出的高分子链断裂-重合-消旋的平衡反应机理.
In isotactic polymethylmethacrylate (iso-PMMA) as the object, using nuclear magnetic resonance spectroscopy and molecular weight determination and other means to study the different physical states, namely, amorphous solid state, crystalline state and dilute solution under radiation pyrolysis And the reaction of radiation.The results showed that in the dilute solution irradiation, the cleavage reaction was strongest and the racemization reaction was the weakest, while the cleavage reaction was the weakest and the racemization reaction was the strongest under the irradiation of crystallization The effect of molecular mobility on the reaction was elucidated, which further validated the equilibrium reaction mechanism of polymer chain rupture, ie, racemization and racemization.