选择性对AB型聚合物的超分子聚合物的影响 AB型聚合物能够产生A x A和A x B相互作用
Tom F A de Greef1, Gianfranco Ercolani, G B W L Ligthart
1Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Journal of the American Chemical Society
|September 20, 2008
概括
研究人员修改了尿素胺 (UPy) 单体,用于高分子聚合. 这种修改减少了自我停止效应,并影响了环链平衡,导致了具有特定相互作用的更窄的分子量分布.
科学领域:
- 超分子化学 超分子化学
- 聚合物科学 聚合物科学
- 有机化学 有机化学
背景情况:
- 超分子聚合依赖于非共价相互作用,如键,以形成链.
- AB型单体可通过异质合 (A x B) 进行聚合,并可经过同质合 (A x A).
- "自封"效应限制了某些超分子系统中的聚合度.
研究的目的:
- 为了研究改性尿素-胺 (UPy) 单体对AB型超分子聚合物的影响.
- 为了减少基于UPy的超分子聚合物的固有"自闭"效应.
- 了解改变的二分化常数和选择性对聚合和循环化的影响.
主要方法:
- 一个新的UPy单体的合成与dibutylamino替代.
- 同型和异型化常数的表征.
- 对度依赖的聚合和环链平衡的分析.
- 开发一个理论模型来预测聚合度,以计算循环化.
- 计算各种聚合场景的分子量分布.
主要成果:
- 新型UPy单体表现出降低的二分化常数,同时保持异分化强度.
- 修改后的单体减少了"自闭"效应,影响了聚合的程度.
- 由于增强的异构关联选择性,观察到循环化趋势的意外增加.
- 一个模型被开发出来,可以准确地预测聚合度,包括同型,异型和循环.
- 发现可逆的A x A相互作用缩小了非循环系统中的分子量分布.
结论:
- 修改UPy单体可以有效调整超分子聚合行为.
- 异质结合中的选择性在聚合程度和循环化方面都起着关键作用.
- 开发的模型为理解复杂的超分子聚合平衡提供了定量框架.
- 可逆同联相互作用的存在可以导致更均的聚合物链长度.
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