In one aspect, the present disclosure encompasses polymerization systems for the copolymerization of CO2 and epoxides comprising 1) a catalyst including a metal coordination compound having a permanent ligand set and at least one ligand that is a polymerization initiator, and 2) a chain transfer agent having one or more sites capable of initiating copolymerization of epoxides and CO2, wherein the chain transfer agent contains one or more masked hydroxyl groups. In a second aspect, the present disclosure encompasses methods for the synthesis of polycarbonate polyols using the inventive polymerization systems. In a third aspect, the present disclosure encompasses polycarbonate polyol compositions characterized in that the polymer chains have a high percentage of - OH end groups, a high percentage of carbonate linkages, and substantially all polycarbonate chains having hydroxyl end groups have no embedded chain transfer agent.
在一个方面,本发明公开了用于
CO2 和
环氧化物共聚的聚合体系,该体系包括 1) 催化剂,该催化剂包括具有永久配位体的
金属配位化合物和至少一种作为聚合
引发剂的配位体;以及 2) 链转移剂,该链转移剂具有一个或多个能够引发
环氧化物和 共聚的位点,其中链转移剂含有一个或多个掩蔽羟基。第二方面,本公开包括使用本发明聚合体系合成聚
碳酸酯多元醇的方法。第三方面,本发明公开了聚
碳酸酯多元醇组合物,其特征在于聚合物链具有高比例的-OH端基、高比例的
碳酸酯链节,并且基本上所有具有羟基端基的聚
碳酸酯链都没有嵌入链转移剂。