Molecular Parameters of Hyperbranched Polymers Made by Self-Condensing Vinyl Polymerization. 1. Molecular Weight Distribution
Molecular Parameters of Hyperbranched Polymers Made by Self-Condensing Vinyl Polymerization. 1. Molecular Weight Distribution
复制标题
DOI：
10.1021/ma9619187
复制
发表时间：
1997-11
期刊：
影响因子：
5.5
通讯作者：
A. Müller;D. Yan;M. Wulkow
中科院分区：
文献类型：
--
作者：
A. Müller;D. Yan;M. Wulkow
计算了一般结构为AB*的单体(“亚胺”)通过自缩合乙烯基聚合(SCVP)形成的超支化聚合物的分子量分布(MWD)及其矩，其中A为乙烯基，B*为引发基。计算的MWD非常宽，多分散性指数(PDI)等于数平均聚合度：Pw/Pn=Pn。它的宽度是AB2型单体缩聚的两倍。如果不考虑未反应单体的含量，相对分子质量变窄，P‘w/P’n≈为0.40P‘n。聚合过程的动力学对乙烯基团的浓度呈一级反应，Pn、Pw和Pdi随时间呈指数增长。理论计算结果与实验数据的对比表明，随着聚合度的增加，活性中心加成到乙烯基团的速率常数减小。由于SCVP中有两个不同的活性中心，因此，NA。
The molecular weight distribution (MWD) and its moments are calculated for hyperbranched polymers formed by self-condensing vinyl polymerization (SCVP) of monomers (“inimers”) with the general structure AB*, where A is a vinyl group and B* is an initiating group. The calculated MWD is extremely broad, the polydispersity index (PDI) being equal to the number-average degree of polymerization: Pw/Pn = Pn. It is twice as broad as that for the polycondensation of AB2 type monomers. If the fraction of unreacted monomer is not taken into account, the MWD becomes somewhat narrower, P‘w/P‘n ≈ 0.40P‘n. The kinetics of the polymerization process are first order with respect to the concentration of vinyl groups; Pn, Pw, and PDI increase exponentially with time. Comparison of the theoretical results with experimental data indicates that the rate constant of addition of an active center to a vinyl group decreases with increasing degree of polymerization. Since there are two different active centers in SCVP, na...