不同聚合机理的“平均聚合度”公式的分析讨论

Analysis and Discussion of“Average Degree of Polymerization”Formula of Different Polymerization Mechanisms

平均聚合度和聚合度分布是决定聚合物产品质量的一个重要指标。平均聚合度直接表征聚合产品的分子量的大小,它的大小又决定高分子材料的性能,因此,研究平均聚合度具有重要的理论意义和实际意义。聚合反应按机理分类,可分为链型聚合和逐步聚合,链型聚合又分为自由基聚合、离子聚合、配位聚合,逐步聚合又分为缩聚和加聚反应。本文以自由基聚合、离子聚合、配位聚合以及缩聚的聚合机理为主线,对不同聚合机理对应的平均聚合度的公式进行推导和讨论,并加深理解,掌握其内涵。旨在提高学生对平均聚合度的认识和把握。

The average degree of polymerization and polymerization degree distribution are important indices for deciding the quality of polymers. The average degree of polymerization represents the size of the molecular weight of polymers and decides the performance of polymeric materials directly,so the study of the average degree of polymerization has important theoretical and the practical significance. According to the polymerization mechanisms, polymerization reaction can be classified into chain polymerization and stepwise polymerization. Among them, chain polymerization includes free radical polymerization, ion polymerization and coordination polymerization; and stepwise polymerization includes polycondensation and addition polymerization. For helping students to understanding and grasping the concept of the average degree of polymerization,the formulae of the average degree of polymerization are derived and discussed based on the polymerization mechanisms.