在金属介导的烯聚合过程中对p-甲基和产生了一种新的连续链转移反应
1Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Journal of the American Chemical Society
|July 18, 2001
概括
这项研究表明,在金属催化烯聚合过程中连续链转移,使得新型聚烯双块共聚物的合成成为可能. 这种创新方法将金属催化转化为活体阳离子聚合.
科学领域:
- 聚合物化学 聚合物化学
- 催化剂是一种催化剂.
- 材料科学 材料科学 材料科学
背景情况:
- 金属催化剂对于olefin聚合是非常重要的.
- 控制聚合物分子量和结构是一个关键的挑战.
- 开发用于合成块共聚合物的新方法是非常可取的.
研究的目的:
- 报告第一个连续链转移在金属催化烯聚合过程中的实例.
- 为了探索聚烯双块共聚物的合成.
- 研究链转移剂对聚合物的影响.
主要方法:
- 使用一种特定的金属复合物 (rac-Me(2) Si[2-Me-4-Ph(Ind) ](2) ZrCl(2) / MAO) 进行烯聚合.
- 引入了p-甲基 styrene (或 styrene) 和作为链传递剂.
- 分析了单体比和聚合物分子量之间的关系.
- 研究了用于随后聚合的终端p-methylstyrene单元的化.
主要成果:
- 实现连续链转移到p-甲基烯 (或烯),然后转移到.
- 聚合物分子重量与p-甲基/和/的摩尔比率呈反比例.
- 连锁转移常量被确定为k{\displaystyle k} /k{\displaystyle k} = 1/6.36和1/7.5,分别.
- 气影响了催化剂活性,但不影响聚合物分子重量.
- 通过化和活离子聚合物成功制备聚烯双块共聚合物 (例如PP-b-PS).
结论:
- 描述的方法为合成难以制备的聚烯双块共聚合物提供了一条新的途径.
- 这一过程有效地将金属催化与活体阳离子聚合结合起来.
- 这项工作扩大了创建先进聚合物架构的可能性.
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