Preparation of Polyacrylonitrile-block-poly(n-butyl acrylate) Copolymers Using Atom Transfer Radical Polymerization and Nitroxide Mediated Polymerization Processes
Preparation of Polyacrylonitrile-block-poly(n-butyl acrylate) Copolymers Using Atom Transfer Radical Polymerization and Nitroxide Mediated Polymerization Processes
复制标题
DOI：
10.1021/ma025894h
复制
发表时间：
2003-02
期刊：
影响因子：
5.5
通讯作者：
Chuanbing Tang;T. Kowalewski;K. Matyjaszewski
中科院分区：
文献类型：
--
作者：
Chuanbing Tang;T. Kowalewski;K. Matyjaszewski
采用原子转移自由基聚合（ATRP）和氮氧自由基聚合（NMP）两种可控自由基聚合（CRP）方法制备了丙烯腈（AN）和丙烯酸正丁酯（n-BA）嵌段共聚物。当从聚（丙烯酸正丁酯）（PBA）到AN的聚合交叉时，在ATRP过程中使用卤素交换改善了聚合的控制。然而，当从聚丙烯腈（PAN）切换到n-BA时，交叉传播在没有卤素交换的情况下得到很好的控制。阻断效率的这些差异可以通过末端碳-卤键的键离解能的差异来解释。在NMP中，从预先形成的PBA嵌段到AN聚合的有效过渡需要过量的氮氧自由基的存在。然而，从PAN到PBA的扩链，即使在均相条件下并且具有过量的氮氧自由基，效率也较低，并且GPC迹线显示双峰性。
The preparation of block copolymers with acrylonitrile (AN) and n-butyl acrylate (n-BA) was examined using two controlled radical polymerization (CRP) processes: atom transfer radical polymerization (ATRP) and nitroxide mediated polymerization (NMP). When crossing from poly(n-butyl acrylate) (PBA) to polymerization of AN, the use of halogen exchange in an ATRP process improved control of polymerization. However, when switching from polyacrylonitrile (PAN) to n-BA, the cross-propagation was well controlled without halogen exchange. These differences in blocking efficiency can be explained by differences in the bond dissociation energy of the terminal carbon-halogen bond. In NMP, an efficient transition from a preformed PBA block to AN polymerization required the presence of excess of nitroxide. However, chain-extension from PAN to PBA, even under homogeneous conditions and with an excess nitroxide, was less efficient, and GPC traces showed bimodality.