自由基聚合的数均聚合度方程及其应用

Equations of Number Average Degrees of Radical Polymerization and Its Applications

自由基聚合的数均聚合度方程及相关参数的测定是教学的重点和难点。高分子合成中,分子量的控制对聚合物的性能又至关重要。文中由数均聚合度的定义出发,引用动力学链长、链转移常数和终止几率的概念,推导出普遍适用的自由基聚合的数均聚合度方程。由此方程导出各种链转移常数和偶合及歧化终止几率的测定方法,给出动力学链长υ的测定方法。推出一个动力学链由偶合终止、歧化终止和向单体、引发剂、溶剂或链转移剂转移生成大分子的数目及各种方式形成大分子的几率。提出聚合度的控制方法。

In this paper, the universally applicable equations of the number average degree of the radical polymerization were deduced from the definition of number average degrees of polymerization and the concepts of the kinetic chain length, the chain transfer constants and the termination probability. The methods to determine the chain transfer constants CM, CI, CS, coupling and disproportionation termination probability C, D were educed. The expressions of kinetic chain length was obtained. The macromolecular numbers of generating by coupling and disproportionation termination, and by transferring to monomer, initiator, solvent or chain transfer agent/or one kinetic chain were calculated. And the generating probability of macromolecular by various ways was also counted. The controlled means of the molecular weight of polymer was presented.