Compartmentalization in Atom Transfer Radical Polymerization of Styrene in Dispersed Systems: Effects of Target Molecular Weight and Halide End Group
Compartmentalization in Atom Transfer Radical Polymerization of Styrene in Dispersed Systems: Effects of Target Molecular Weight and Halide End Group
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DOI：
10.1021/ma900035x
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发表时间：
2009-04-14
期刊：
影响因子：
5.5
通讯作者：
Okubo, Masayoshi
中科院分区：
文献类型：
--
作者：
Zetterlund, Per B.;Kagawa, Yasuyuki;Okubo, Masayoshi
使用修正的 Smith-Ewart 方程，在分散体系中，在 70 或 75 摄氏度下以低转化率使用聚苯乙烯-X/CuX/4,4'-二壬基-2,2'-联吡啶 (dNbpy)（X = Br 或 Cl），对苯乙烯原子转移自由基聚合 (ATRP) 动力学的区室化效应进行了理论上的研究。区室化总是会导致活性（最终功能）的改善，因为传播自由基的分离效应降低了总体终止率。然而，只有当颗粒足够小时，才能改善对分子量分布的控制；也就是说，存在活性得到改善但控制没有得到改善的粒径范围。由于有限空间效应导致失活率增加，因此获得了改进的控制。如果 Br 被 Cl 取代，区室化的程度会随着目标分子量的增加而增加。目前的工作进一步深入了解如何利用粒径作为影响 ATRP 的实验参数。
Compartmentalization effects on the kinetics of the atom transfer radical polymerization (ATRP) of styrene employing polystyrene-X/CuX/4,4'-dinonyl-2,2'-dipyridyl (dNbpy) (X = Br or Cl) in a dispersed system at low conversion at 70 or 75 degrees C have been investigated theoretically using modified Smith-Ewart equations. Compartmentalization always leads to improved livingness (end functionality) because of the segregation effect on propagating radicals reducing the overall termination rate. The control over the molecular weight distribution is, however, only improved if the particles are sufficiently small; that is, a particle size range exists where livingness is improved but control is not. Improved control is obtained as a result of the confined space effect causing an increase in the deactivation rate. The extent of compartmentalization increases with increasing target molecular weight and if Br is replaced with Cl. The present work provides further insight into how one can potentially employ particle size as an experimental parameter to influence ATRP.