摘要
在从均相稀土Ziegler-Natta催化剂中分离出有双烯聚合活性的Nd-Al双金属配合物的基础上,利用该配合物可在无助催化剂烷基铝存在下单独引发丁二烯聚合的特性,详细研究了活性体、外加烷基铝、单体浓度,温度及时间等变量对聚合的影响;对比了活性体引发聚合与一般Ziegler-Natta催化聚合在一般规律上的异同。以更客观的实验事实论证了烷基铝在聚合过程中的作用,通过聚合产物的GPC测定讨论了活性体聚合中存在的键转移反应,确认外加烷基铝的键转移能力最强。所得结果有助于对稀土催化定向聚合过程的深入了解。
Based on the isolation of polynuclear Nd-Al bimetallic complex,which can initiate diene polymerization alone in the absence of co-catalyst irialkyl aluminium, the effects of active species, additional trialkyl aluminium, monomer concentration, polymerization temperature and time on butadiene polymerization were studied in detail. A comparison between the features of . polymerization initiated by active species and by conventional Ziegler-Natta catalyst was made. The function of trialkyl aluminium in the Ziegler-Natta catalytic polymerization was expounded and proved by more objective experimental facts. In the light of GPC measurement, the chain transfer reactions in the active species initiating polymerization were discussed. It is found that the additional trialkyl aluminium has the strongest chain transfer ability among above-mentioned variables. The results are useful for deepgoing understanding of the stereospecific polymerization catalyzed by rare earth. ?
基金
国家自然科学基金
