申请人:Schultz Laura G.
公开号:US20090326149A1
公开(公告)日:2009-12-31
Methods for making a branched polycarbonate are disclosed. An interfacial mixture comprising water, a substantially water-immiscible organic solvent, a dihydroxy compound, a polyhydric branching agent, an endcapping agent, a catalyst, and a base is formed. The base and the branching agent are dissolved in the mixture before the dihydroxy compound is added, and the interfacial mixture has a basic pH. The mixture is reacted by adding a carbonate precursor to the mixture while maintaining the pH between about 8 and about 10 to form the branched polycarbonate. The resulting branched polycarbonates may contain more than 1.5 mole % of the THPE; have residual chloride content of 20 ppm or less; and a weight average molecular weight of about 55,000 or less. They may also be highly transparent.
公开了制备分支聚碳酸酯的方法。形成了一个界面混合物,包括水、基本上与水不相溶的有机溶剂、二羟基化合物、多羟基分支剂、端基化剂、催化剂和碱。在添加二羟基化合物之前,将分支剂和碱溶解在混合物中,使界面混合物具有碱性pH。通过在维持pH在约8到约10之间的情况下向混合物中添加碳酸酯前体来反应混合物,从而形成分支聚碳酸酯。所得到的分支聚碳酸酯可能含有超过1.5摩尔%的THPE;残留氯含量不超过20 ppm;重量平均分子量约为55,000或更低。它们也可能具有高度透明性。