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化学学报
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化学学报 ›› 2011, Vol. 69 ›› Issue (07): 853-862. 上一篇    

研究论文

苯乙烯的低温原子转移自由基聚合: 扩散效应导致的加速现象

方艳，翟光群*，蒋必彪，陈建海   

  1. (常州大学材料科学与工程系 常州 213164)
  • 投稿日期:2010-07-08 修回日期:2010-11-10 发布日期:2010-12-09
  • 通讯作者: 翟光群 E-mail:zhai_gq@cczu.edu.cn
  • 基金资助:

    国家自然科学基金项目;江苏省自然科学基金

Low-Temperature Atom Transfer Radical Polymerization of Styrene: Diffusion-induced Acceleration

FANG Yan, DI Guang-Qun, JIANG Bi-Biao, CHEN Jian-Hai   

  1. (Department of Materials Science and Engineering, Changzhou University, Changzhou 213164)
  • Received:2010-07-08 Revised:2010-11-10 Published:2010-12-09
  • Contact: Zhai Guangqun E-mail:zhai_gq@cczu.edu.cn

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1528

被引次数

6

研究了以苯乙烯(St)和N-[4-(2-溴丙酰氧基)苯基]马来酰亚胺(BPPM)的交替共聚物P(St-alt-BPPM)为大分子多官能度引发剂, 以CuBr/2,2 -联吡啶(bpy)为催化体系, 环己酮为溶剂, 在60或80 ℃下进行St的原子转移自由基聚合(ATRP). 结果表明, 反应呈现活性聚合的假一级反应动力学特征, 聚合物分子量随着单体转化率上升而增加, 降低反应温度将减低反应速率, 但是所得聚合物[P(St-alt-BPPM)-g-PS]分子量分布更窄. 水解实验证明该过程具有一定可控性. 由于类似的单官能度引发剂无法在同等条件下顺利引发St的ATRP, 因此采用大分子多官能度引发剂可以大幅度降低ATRP的反应温度. 此加速现象被归因于CuBr/bpy从大分子引发剂线团外向线团内扩散, 而CuBr2/bpy则从大分子引发剂线团内向线团外扩散, 从而提高大分子引发剂线团中的自由基浓度和聚合反应速率.

关键词: 苯乙烯, 原子转移自由基聚合, 大分子多官能度引发剂, 扩散效应, 加速

The CuBr/2,2 -bipyridine (bpy)-catalyzed atom transfer radical polymerization (ATRP) of styrene (St) initiated by well-defined poly(styrene-alt-N-[4-(α-bromopropyloxy)phenyl]maleimide) [P(St-alt-BPPM)] in cyclohexanone at 60 and 80 ℃ was investigated. The results showed that the reaction appeared to follow pseudo-first order kinetics, and the molecular weight (MW) of the polymer P(St-alt-BPPM)-g-PS increased with the monomer conversion. A lower reaction temperature would reduce the reaction rate and lead to a narrower molecular weight distribution of the P(St-alt-BPPM)-g-PS. The MW data of the PS side chains confirmed that the process was in a controlled fashion. The ATRP of St cannot be successfully initiated by low-MW analogue under similar conditions, so using multi-functional macroinitiator would significantly reduce the reaction temperature. Such an acceleration effect was attributed to the diffusion of CuBr/bpy from the macro-initiator coil outside to inside and that of CuBr2/bpy from inside to outside, resulting in an enhanced concentration of propagating radicals inside the coil and an faster polymerization rate.

Key words: styrene, atom transfer radical polymerization (ATRP), multi-functional macroinitiator, diffusion effect, acceleration