以NdCl3.4L(配体L为膦酸三丁酯TBP、膦酸三苯酯TPP、膦酸二异辛酯P204)为主催化剂(简称[Nd])、甲基铝氧烷(MAO,简称[Al])为助催化剂和环己烷为溶剂,进行1,3-丁二烯聚合的研究.考察了配体对丁二烯聚合反应活性的规律及MAO用量、催化剂陈化时间、溶剂种类对聚合的影响;并对聚合物进行NMR,IR和GPC的表征.结果表明,3种配体的聚合活性顺序为TBP〉P204〉TPP;当[Al]/[Nd]为30时,聚合物的分子量分布指数达到1.20;30℃陈化时,聚丁二烯cis-1,4结构均大于97%;与正己烷、甲苯溶剂对比来看,环己烷体系所得聚合产物的分子量分布相对较窄、产率较高.
By using the neodymium chloride compounds([Nd])[NdCl3·4L,L:TBP (tributyl phosphate),TPP(triphenyl phosphate),P204(di(2-ethylhexly)phosphoric acid)] as the catalyst while the methylaluminoxane ([Al]) as the cocatalyst,the polymerization of 1,3-butadiene could be carried out in cyclohexane to obtain high cis-content and narrow molecular weight distribution polybutadienes.In this article,the polymerization activities,and the molecular weight,the molecular weight distribution and the microstructure of the products were examined on the basis of the the effects of the ligands,the amounts of the methylaluminoxane,the aging time and the solvents on the 1,3-butadiene polymerization.It was considered that the polymerization activities of the ligands were in the order of TBP 〉 P204〉 TPP,which was attribute to the differences among the electron donor group inductive effect of the ligands; when the [Al]/[Nd] was 30,the GPC curve was unimodal,indicating the single-active-site in the polymerization process,which revealed that the molecular weight distribution was narrow (1.20).By means of aging at 30℃,the cis-content of polybutadienes were over 97.2% which was determined by IR and confirmed by NMR.Compared with toluene and hexane,by using cyclohexane as the polymerizing solvents,high cis-content and narrow molecular weight distribution polybutadienes were obtained and the catalyst system was at the highest polymerization activity,which revealed that the cyclohexane was the proper solvent for the polymerization.