用钛系载体高效催化剂进行乙烯-丙烯-1-丁烯三元共聚合的研究 Ⅱ.共聚物的结构表征

通过各种表征手段对用TiCl_4,Ti(OBu)_4/MgCl_2/EB/φSiCl_2/AlEt_3催化剂合成的乙丙丁三元共聚物进行了剖析。发现在一定组成范围内,三元共聚物不含庚烷不溶物。DSC和WAXD分析检测不到结晶相。用~(13)C-NMR技术表征了在相同条件下合成的乙丙、乙丁及丙丁三组二元共聚物的序列分布。结果表明,乙丙和乙丁共聚物的序列结构可用一级Markov分布描述。丙丁共聚物则服从Bernoulli分布,用~(13)C-NMR方法计算了乙丙丁三元共聚物的化学组成,并初步考察了共聚物硫化胶的力学性能。

TERPOLYMERIZATION OF ETHYLENE,PROPYLENE AND 1-BUTENE WITH HIGHLY ACTIVE SUPPORTED TITANIUM CATALYST II.Characterizations of the Terpolymers

The characterization of ethylene-propylene-1-butene terpolymers synthesized by TiCl4, Ti (OBu)4/MgCl2/ethylbenzoate/ 2SiCl2/AlEt3 catalyst is described. DSC, WAXD analysis and solvent extraction show that the EPB terpolymers in a certain range of composition are elastomers without detectable crystallinity, which demonstrates a rather random structure and makes them promising for quality rubber. The comonomer sequence distributions are, by 13C-NMR analysis of binary copolymers, first-order Markovian for EP and EB copolymers but Bernoul-lian for PB copolymer. Three pairs of monomer reactivity ratios were evaluated. The assign-memts of the chemical shifts in the 13C-NMR spectra of EPB terpolymer was made and a method was proposed to determine the chemical composition of the EPB terpolymers.