阳离子烷基钪配合物催化体系催化乙烯与丙烯共聚合的研究

双烷基钪配合物LSc(CH2SiMe3)2(L=(2,6-iPr2C6H3)NC(Me)CHPPh2N(2,6-Me2C6H3))在助催化剂Ph3C]B(C6F5)4]的作用下能够高活性地催化乙烯和丙烯共聚.在反应温度30℃和乙烯与丙烯常压(1.0×105Pa)下聚合,共聚活性能够达到7.5×105g(PE)mol-1h-1(105Pa)-1.单体的竞聚率分别为rE=29.75和rP=0.015.13C-NMR和DSC分析表明所得到的乙丙共聚物是弹性体,且丙烯单体无规分布在共聚物链中.

COPOLYMERIZATION OF ETHYLENE AND PROPYLENE BY CATIONIC SCANDIUM ALKYL CATALYST SYSTEM

The scandium dialkyl complex LSc(CH2SiMe3)2(L=(2,6-iPr2C6H3)NC(Me)CHPPh2N-(2,6-Me2C6H3)) activated with B(C6F5)4] could initiate ethylene and propylene copolymerization with high activity(7.5×105g(PE)mol-1 h-1(105Pa)-1) under the conditions of room temperature(30 ℃) and atomphere pressure(1.0 × 105 Pa).The influence of comonomer feed content and polymerization temperature on activity and the composition of the copolymers using LSc(CH2SiMe3)2/B(C6F5)4] catalytic system were investigated.An increase in the initial propylene feed content leads to the increase in the incorporated propylene content of the resulting copolymer.At 30 ℃,the highest activity and incorporation of propylene were achieved.Determination of the reactivity ratios shows a much high reactivity for ethylene(rE=29.75 and rP=0.015).The resultant copolymers are elastomers having random sequence distibution of the two monomeric units evidenced by 13C-NMR spectroscopy and DSC analyses.