在Ni(naph)2-AlR3-(BF3·OEt2)催化体系(简称Ni-Al-B)用于丁二烯(Bd)/己烷进行配位聚合体系中引入N,N-二甲基乙醇胺(DMEA)和辛醇(OctOH),研究了DMEA/Ni摩尔比、B/Ni摩尔比和Al/Ni摩尔比对Bd聚合转化率、聚丁二烯(PB)产物的特性黏数、分子量、分子量分布及微观结构的影响,进一步探讨聚合反应动力学.结果表明,在镍系催化丁二烯聚合体系中引入一定量的DMEA和OctOH后,可以提高顺-1,4微观结构含量至97.8%,降低1,2-微观结构含量至约1.3%,提高分子量,使分子量分布变窄,并降低凝胶含量.进一步通过调节B/Ni及Al/Ni摩尔比值,可得到[η]为2.0~4.0dL/g的高顺式PB.聚合速率对单体浓度呈现一级动力学关系,表观增长活化能为43.7kJ·mol-1。
The coordination polymerization of 1,3-butadiene was conducted with Ni(naph)2 /A1R3 /BF3.OEt2 catalyst system in the presence of N,N-dimethyl ethanolamine(DMEA) and octanol(OctOH) in hexane at 50℃.The effects of molar ratios of DMEA /Ni,B /Ni and Al /Ni on monomer conversion,intrinsic viscosity([η]),molecular weight,molecular weight distribution and microstructure of polybutadiene(PB) were investigated.The kinetic study was also conducted for this polymerization at different temperatures ranging from 20℃ to 50℃.The results showed that DMEA and OctOH played very important roles in modifying molecular weight,molecular weight distribution and microstructure.By comparison,the molecular weight of polybutadiene products could be greatly increased,molecular weight distribution narrowed and cis-1,4 content of Bd units in polymer chain increased to 97.8% and 1,2-content decreased to 1.3% by introducing adequate amounts of DMEA and OctOH,leading to more crystalline and less gel content.Furthermore,the intrinsic viscosity([η]) of polymer products could also be modulated by changing the molar ratios of B/Ni and Al /Ni in the range of 2.0 ~ 4.0 dL /g.The polymerization was in first order with respect to monomer concentration at different polymerization temperatures.The apparent activation energy for propagation was determined to be 43.7 kJ.mol-1.