Study on influence of the tali chain of macromonomers on the radical chain polymerization

大分子单体由可聚合端基和尾链组成。在这项研究中，甲基丙烯酸酯以及乙烯基苄基封端的聚苯乙烯大分子单体的自由基链聚合进行了研究，以了解连接到可聚合端基的尾链的影响。用GPC和ESR谱测定了溶液聚合的聚合速率Rp、产物聚合度DP、增长反应和终止反应的速率常数kp和kt。采用活性阴离子聚合技术制备了不同分子量的大分子单体。结果表明，尾链长度和进料中大分子单体浓度[M]对k_t有很强的依赖性，而尾链长度和[M]对k_t的依赖性不明显。在高于尾链玻璃化转变温度的温度下进行了熔融本体聚合，结果显示了较强的扩散控制效应和平衡单体浓度的影响。此外，聚合产物的分子性质和介晶相的形成，即，聚（大分子单体）的，也进行了研究，以澄清的多支化增长链的性质和结构的形成，在聚合介质中。

Macromonomers are composed of a polymerizable end group and a tail chain. In this study, radical chain polymerization of methacrylate as well as vinylbenzyl terminated polystyrene macromonomers was investigated to understand the influence of the tail chain connected to the polymerizable end group. Polymerization rate, Rp, degree of polymerization of the product, DP, and the rate constants for propagation and termination reactions, k_p and k_t, in the polymerization in solution were measured by using GPC and ESR spectrum. The macromonomers with different molecular weights were prepared by the living anionic polymerization technique. It was found that the k_t strongly depended on both the tail chain length and the macromonomer concentration in feed [M], while k_t did not show a clear dependence on the tail chain length and the [M]. Bulk polymerizations in melt state at higher temperature than the glass transition temperature of the tail chain were also carried out, the results of which showed the strong diffusion control effect and the influence of the equilibrium monomer concentration. Furthermore, the molecular properties and the mesomorphic phase formation of the polymerization products, i.e., poly(macromonomer)s, were also investigated to clarify the nature of the multibranched propagating chain and the structure formation in polymerization media.