负载钛-三异丁基铝体系催化苯乙烯聚合——Ⅰ．聚合条件对苯乙烯聚合的影响

Polymerization of styrene catalyzed by supported titanium catalyst and Al(i-Bu)_3 Ⅰ.Effect of reaction conditions on polymerization of styrene

考察了负载钛(简称Ti)-三异丁基铝(简称Al)催化体系聚合条件对苯乙烯(St)聚合的影响实验表明：随着n(Al)/n(Ti)的增加,催化剂效率先升高后降低,最高为12kg/(mol·h)。随着聚合温度升高,催化剂效率逐渐升高,但增幅逐渐减缓。最佳聚合条件：St初始浓度为5mol/L,Ti浓度为1.3mmol/L,n(Al)/n(Ti)为30,聚合温度为60℃；同时,聚合物的相对分子质量和全同立构含量均随n(Al)/n(Ti)和聚合温度升高而降低,全同立构含量可通过调节n(Al)/n(Ti),使之在40.4%～90.0%。

This paper examined the effects of reaction conditions on polymerization of styrene in the presence of a catalytic system consisting of supported titanium (abbreviated to Ti) and triisobutyl aluminum (abbreviated to Al).The experiments reveal that as the ratio n(Al)/n(Ti) increases,the catalytic efficiency varies in a way of initially going up and then going down with a maximum value of 12 kg/(mol·h).As the polymerization temperature rises,the catalytic efficiency increases,but the increment amplitude is gradually reduced.The optimum polymerization conditions involve initial concentration of styrene of 5 mol/L,Ti concentration 1.3 mmol/L,n(Al)/n(Ti) 30 and polymerization temperature 60℃.Both relative molecular mass and isotacticity index of the polymer decrease with increasing n(Al)/n(Ti) and polymerization temperature.The isotacticity index can be controlled in the range of 40.4%-90.0% by adjusting n(Al)/n(Ti).