通过有机介导的立体选择性协调/插入性同聚合和 styrene 和甲基甲酸甲基酸盐的共聚
Tryg R Jensen1, Sung Cheol Yoon, Aswini K Dash
1Chemistry Department, Northwestern University, Evanston, IL 60208-3113, USA.
Journal of the American Chemical Society
|November 20, 2003
概括
一种新型的有机催化剂使得烯和甲基甲基酸盐 (MMA) 的立体规律聚合成为可能. 这种催化剂产生合成聚乙烯 (s-PS) 和聚甲基酸 (s-PMMA),并独特地共聚化MMA和烯.
科学领域:
- 有机金属化学 有机金属化学
- 聚合物科学 聚合物科学
- 催化剂是一种催化剂.
背景情况:
- 聚氨酸的立体规律聚合对于定制聚合物特性至关重要.
- 开发单位催化剂,用于控制多种单体的聚合,仍然是一个挑战.
- 了解共聚合机制是设计先进材料的关键.
研究的目的:
- 通过使用一种新型的有机催化剂,研究 styrene 和甲基甲酸盐 (MMA) 的聚合和共聚化行为.
- 阐明由这种单位催化剂介导的立体规律同聚合和共聚合的机制.
- 探索这种催化剂系统在制造具有控制微观结构的新型共聚合物方面的潜力.
主要方法:
- 通过在位Zn降解制备高活性单位有机催化剂.
- 使用开发的催化剂对 styrene 和 MMA 的同聚合.
- 在各种条件下, styrene 和 MMA 的共聚合,然后进行机械控制实验.
主要成果:
- 催化剂通过协调/插入途径有效地产生了协同毒性聚乙烯 (s-PS,≥95%的协同毒性,170,000 g/mol).
- 同一个催化剂通过类似GTP的机制产生了联合毒性聚甲基酸 (s-PMMA,≥65%联合毒性,≥70,000 g/mol).
- 在50°C的烯和MMA (1:19比) 的共聚合导致随机的,约80%的同位素聚[烯-co-(甲基甲酸) ] (coiso-PSMMA) 含有~4%的MMA,这表明一种新的结合添加机制.
结论:
- 一个单位的有机催化剂有效地调解了 styrene 和 MMA 的立体规律同聚合.
- 催化剂在聚乙烯和MMA的共聚合方面表现出独特的能力,挑战了现有的非协调机制.
- 提出了一种涉及连续并联加法步骤的新机制,以解释观察到的共聚合行为.
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