• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >How to polymerize ethylene in a highly controlled fashion?
【24h】

How to polymerize ethylene in a highly controlled fashion?

机译：如何以高度受控的方式聚合乙烯？

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Very fast, reversible, polyethylene (PE) chain transfer or complex-catalysed "Aufbaureaktion" describes a "living" chain-growing process on a maingroup metal or zinc atom; this process is catalysed by an organo-transition-metal or lanthanide complex. PE chains are transferred very fast between the two metal sites and chain growth takes place through ethylene insertion into the transition-metal- or lanthanide-carbon bond-coordinative chain-transfer polymerisation (CCTP). The transferred chains "rest" at the maingroup or zinc centre, at which chain-termination processes like P-H transfer/elimination are of low significance. Such protocols can be used to synthesise very narrowly distributed PE materials (M-w/M-n < 1.1 up to a molecular weight of about 4000 gmol(-1)) with differently functionalised end groups. Higher molecular-weight polymers can be obtained with a slightly increased M-w/M-n, since diffusion control and precipitation of the polymers influences the chain-transfer process. Recently, a few transition-metal- or lanthanide-based catalyst systems that catalyse such a highly reversible chaingrowing process have been described. They are summarised and compared within this contribution.
机译：非常快速，可逆的聚乙烯（PE）链转移或复杂催化的“ Aufbaureaktion”描述了在主族金属或锌原子上的“活性”链增长过程;该过程由有机过渡金属或镧系元素络合物催化。 PE链在两个金属位点之间非常快速地转移，并且链增长是通过将乙烯插入过渡金属或镧系元素-碳键-配位链转移聚合（CCTP）中进行的。转移的链“停留”在主族或锌中心，在这些中心，像P-H转移/消除这样的链终止过程意义不大。此类协议可用于合成功能分布不同的端基的分布非常狭窄的PE材料（M-w / M-n <1.1，直至分子量约为4000 gmol（-1））。可以以稍微增加的M-w / M-n获得更高分子量的聚合物，因为聚合物的扩散控制和沉淀影响链转移过程。最近，已经描述了一些催化这种高度可逆的链增长过程的基于过渡金属或镧系元素的催化剂体系。在此贡献中对它们进行了总结和比较。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号