溴化聚烯烃橡胶的合成研究

考察了限定几何构型(CGC)钪配合物{Flu-(CH2)3-NHC}Sc(CH2SiMe3)2催化10-溴-1-癸烯(BrDC)与丙烯、乙烯两元及三元共聚合的性能,获得了一系列溴化聚烯烃橡胶,通过核磁共振波谱(NMR)、凝胶渗透色谱(GPC)和示差扫描量热(DSC)对所获溴化聚烯烃橡胶的结构和热性能进行了分析.结果表明,室温下CGC钪催化BrDC均聚合60 min,即以91%的收率获得高分子量(Mn=6.5×10^(4)g·mol^(-1))的无规聚合物.在0.2 MPa的丙烯压力下,CGC钪对BrDC和丙烯共聚合也表现出了极高的催化活性(106 g聚合物·molSc^(-1)·h^(-1)),通过改变BrDC用量,获得了BrDC含量在1.1 mol%~18.0 mol%间调控的高分子量(Mn=1.35×10^(5)~1.88×10^(5)g·mol^(-1))丙烯-BrDC无规共聚物.丙烯-BrDC无规共聚物中包含孤立分布的BrDC和无规聚丙烯嵌段.不同组成的丙烯-BrDC共聚物在-7~-33℃范围内具有一个玻璃化转变温度(Tg).该CGC钪对乙烯、丙烯和BrDC三元共聚合也表现出了极高的催化活性(106 g聚合物·molSc^(-1)·h^(-1)),获得了组成可控、高分子量(Mn=2.31×10^(5)~3.27×10^(5)g·mol^(-1))的乙烯-丙烯-BrDC三元无规共聚物.不同组成的三元共聚物在-43~-59℃范围内具有一个Tg,当三元共聚物中乙烯含量高于67.0 mol%时三元共聚物具有一个约100℃的熔点.

Neodymium-catalyzed Polymerization of C5 Fraction: Efficient Synthesis of 1,3-Pentadiene-isoprene Copolymer Rubbers

The polymerization of C5 fraction without separation and concentration by using a commercial available Nd(P204)3/ AliBu3/AlEt2Cl has afforded for the first time a new kind of 1,3-pentadiene-isoprene random copolymers as rubber materials. Isoprene (IP) and E-1,3-pentadiene (EPD) acted as polymerization monomers, cyclopentadiene acted as poison, and other substances like alkanes, monoolefins, Z-1,3-pentadiene acted as solvents in this multicomponent C5 fraction polymerization system. The data of kinetic experiments, NMR, and DSC indicated that the polymerization of C5 fraction by Nd(P204)3/AliBu3/AlEt2Cl afforded the IP-EPD random copolymers. By controlling polymerization conditions such as [Al]/[Nd]/[Cl] molar ratio and polymerization temperature, the random EPD-IP copolymers containing high cis-1,4-poly(IP)(with selectivity 96%) and moderate cis-1,4-poly(EPD)(with selectivity 60%) units with a low glass transition temperature (about 60 ℃), controllable molecular weight (Mn = 3.8 × 10^4-14.3 × 104), and moderate molecular weight distribution (Mw/Mn = 2.17-2.78) were obtained in a high yield.