钼体系聚1,2-丁二烯分子量及其分布

THE MOLECULAR WEIGHT AND ITS DISTRIBUTION OF 1,2-POLYBUTADIENE PREPARED WITH MOLYBDENUM CATALYST SYSTEM

本文用粘度法和GPC法研究了MoCl_4R-i-Bu_2AlOR′催化体系合成的聚1,2-丁二烯的分子量及其分布,发现该体系聚合物分子量分布非常窄,且与聚合温度呈直线关系;利用外推法估计,在-18℃左右该体系有可能引发活性聚合。聚合温度为30—70℃时,聚合物分子量分布宽度指数为1.5—2.0。本文还研究了调节聚合物分子量及其分布的方法,发现烯丙基卤可以大幅度调节聚合物分子量,对分子量分布也有一定的调节作用,其中烯丙基碘的效果最好。

The investigation on the molecular weigth and its distribution of 1,2-polybuta-diene prepared with MoCl4OR-i-Bu2AlORn catalyst system has been performed by viscosity and GPC methods and the way for regulation of the molecular weight and distribution has been searched. 1,2-polybutadiene with Mw/Mn = 1.2-2.0 can be prepared with MoCL4OR-i-Bu2AlOR' catalyst system at 30-70℃. There is a linear relation between the Mw/Mn and polymerization temperature. It was found by extrapolating that this catalyst system can possibly initiate living polymerization at about - 18℃. The molecular weigth and its distribution can be regulated by polymerization temperature or presence of polar additive compounds. Allyl halides are very effective for this purpose and allyl iodide is the best.