摘要
除了用Ｍｗ，Ｍｎ和Ｍｗ／Ｍｎ表征聚碳酸酯（ＰＣ）分子量大小和分布宽度外，还采用了（Ｍｐ－Ｍ１０）和（Ｍ９０－Ｍｐ）来表征低分子量和高分子量尾端所延伸的宽度，并以两尾端的起始分子量作为参考参数。其中Ｍｐ为分子量微分分布曲线峰位分子量，而Ｍ１０和Ｍ９０则为累积分布曲线中１０％和９０％处的分子量。研究了这些参数与聚碳酸酯热降解的关系，发现除数均分子量外，高低分子量尾端部分与ＰＣ热稳定性关系密切，尤其是低分子量尾端分布状态和起始分子量大小，对ＰＣ热稳定性更为敏感。这与ＰＣ端ＯＨ基相对浓度同ＰＣ热降解率的关系相一致。
Besides using M w ,M n and polydispersity index of MWD(M w /M n ) to characterize the molecular size and breadth of MWD,the expressions (M p M 10 )and(M 90 M p )can also be used to characterize the breadth of MWD curve emphasizing the extent of the low and high molecular ends of the distribution.In these expressions, M p is the peak MW of the differential distribution curve,and M 10 and M 90 signify MW at 10% and 90% cumulative weight of the integral distribution curve.At the same time, both molecular weights of the low and the high ends of the differential distribution curve are used as reference parameters.Besides the number average molecular weight M n ,the low and high molecular ends of the distribution curve bear close relationship to the heat stabitity of polycarbonate,to which the distribution state and magnitude of the initial molecular weight are especially highly sensitive.These results are well in agreement with the relation between the relative concentration of the hydroxy end group and heat degradation properties of polycarbonate.
出处
《石油化工》
CAS
CSCD
北大核心
1997年第11期750-754,共5页
Petrochemical Technology
