Sc(P_(204))_3/烷基铝体系催化降冰片烯聚合

POLYMERIZATION OF NORBORNENE CATALYZED BY Sc(P_(204))_3/ALKYL ALUMINIUM SYSTEM

以钪的膦酸酯盐Sc(P204)3和烷基铝组成催化体系催化降冰片烯(NBE)聚合,考察了聚合反应条件对单体转化率、产物分子量以及微观结构的影响.当以三乙基铝为助催化剂时,[NBE]/[Sc]=50(摩尔比),[Al]/[Sc]=30(摩尔比),40℃陈化5 min,在甲苯中于60℃聚合7 h,单体转化率为98%,所得聚合物可部分溶于有机溶剂;NBE以开环聚合方式为主,开环产物含量为81%～88%,其中顺式双键含量为48%～58%,分子量2.4×103～3.0×103,分子量分布1.9～2.2.当以三异丁基铝为助催化剂时,[NBE]/[Sc]=50(摩尔比),[Al]/[Sc]=5(摩尔比),50℃陈化2 h,80℃下于甲苯中聚合4 h,单体转化率为39%,所得白色聚合产物很难溶于有机溶剂,以开环聚合方式为主,产物中反式双键含量90%.

Polymerization of norbornene （NBE） was carried out using scandium phosphonate （ Sc （ P204 ） 3 ） combined with alkyl aluminium as catalysts. 13C-NMR, 1H-NMR and FTIR analyses indicate that the PNBE are mainly prepared by the ring-opened type polymerization,and also show ring-retention to varying degrees in this type of catalytic system. It was found that alkyl aluminium cocatalyst plays an important role in the polymerization. Catalyzed by Sc （ P204 ） 3/AI-iBu3 system under the optimal polymerization conditions ： n （AI） / n（Sc） = 5 aging at 50℃ for 2 h, n （NBE）/n （Sc） = 50, polymerization at 80~C for 4 h producing a insoluble and crosslink polymer with 39% yield was obtained. While AlEt3 was used as eoeatalyst,the PNIJE obtained are partly soluble in organic solvents with 98% yield under the optimal polymerization conditions： n （A1）/ n （Sc） = 30 aging at 40 ~C for 5 min, n （NBE）/n （Sc） = 50, polymerization at 60℃ for 7 h. Measured by GPC, the soluble fraction of PNBE exhibits low molecular weight Mn = 2.4 × 103 - 3.0 × 103 with moderate molecular weight distributions （MWD = 1.9 -2.2）. The soluble fraction of PNBE consists of 81% - 88% ring-opened type polymer with 48% - 58% cisdouble carbon bond content.