HTGPC法分析不同聚合条件下的乙烯均聚物

Analysis of Homopolyme of Ethylene in Different Polymerization Process with HTGPC

通过高温凝胶渗透色谱对茂金属催化合成的一系列乙烯均聚物进行了分析,可以看出Al/Ti比从1 000变到4 000时,分子量分布曲线图变化不大,而从4 000变到7 000时,变化相当大,分布宽度从2.48增至2.81;催化剂D的活性最小,可作为非对称性茂系金属催化剂;该聚合体系分子量的大小受聚合温度的影响很明显,随温度的升高,分子量分布曲线图向左发生很大位移,在聚合温度为70℃时存在两个活性相当的活性中心.

A series homopolyme of ethylene synthesised by metallocene catalyst was analyzed by the high temperature gelatin permeation chromatography. The results showed that the molecular weight distribution changed not too much when the ratio of Al/Ti ranging between 1 000 and 4 000, while the molecular weight distributed increased from 2.48 to 2.81 when the ratio ranging between 4 000 and 7 000; catalyst D had the lowest activity to be used as asymmetric metallocene catalyst; the curve of molecular weight moved much to the left with the increases of temperature and two active centres appeared when the temperature is 70 ℃.