兹维特里昂聚合:一种用于循环聚化的受控合成的动力学策略
Wonhee Jeong1, Eun Ji Shin, Darcy A Culkin
1Department of Chemistry, Stanford University, Stanford, California 94305, USA.
Journal of the American Chemical Society
|April 2, 2009
概括
由N-异环碳素启动的zwitterionic环开聚合迅速产生具有受控分子量的循环聚合物. 动力学研究揭示了一种机制,解释了对分子重量和狭窄分布的精确控制,从而实现了优化聚合成.
科学领域:
- 聚合物化学 聚合物化学
- 有机合成 有机合成
- 材料科学 材料科学 材料科学
背景情况:
- 环开聚合 (ROP) 是合成聚的关键方法.
- 控制ROP中的分子量和分布对于材料性能至关重要.
- 兹维特里奥尼克ROP为聚合物合成提供了独特的机械路径.
研究的目的:
- 研究由N- heterocyclic carbenes启动的zwitterionic环开放聚合物的动力学和机制.
- 了解控制这个系统中的分子量和多分散性的因素.
- 开发一种动力模型,合理化观察到的聚合行为.
主要方法:
- 使用N-异环碳素启动剂的乳化物的Zwitterionic环开聚合.
- 动力学和机械学研究,包括速率常数的确定.
- 聚合化动力学的数值和随机模拟.
- 链延伸实验验证拟议的机制.
主要成果:
- 聚合迅速产生周期性多聚化物,其分子量可控 (5,00030,000 g/mol) 并且具有狭窄的多分散性 (<1.31).
- 动力学分析揭示了一种具有缓慢的二次启动,快速传播和竞争性循环和消散步骤的机制.
- 模拟解释了分子重量增加与转换和不敏感的发起器比率,归因于狭窄的分布,以高的传播率.
结论:
- 这项研究阐明了lactide的zwitterionic ROP的独特动力特征.
- 为优化精确定义的循环聚合物的合成提供了一个机制框架.
- 这些发现支持了这种方法在受控聚合物合成方面的潜力.
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