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用13C NMR测定了由单茂基钛化合物 /mMAO催化体系制备的乙烯 /丙烯共聚物大分子链的立体结构和单体序列分布 ,计算了单体的竞聚率r1=7 91± 0 0 6 ,r2 =0 135± 0 0 3 ,其乘积r1r2 ≈ 1.Fineman Ross计算得到的单体竞聚率与13C NMR测定值相近 ,即r1=7.94,r2 =0 .134,其乘积r1r2 =1 0 4.这表明共聚物是立构无规的 .共聚物经溶剂萃取后 ,乙醚可溶和己烷可溶两个级分中单体的序列分布和竞聚率略有不同 .乙醚可溶级分中丙烯链段稍长 ,而己烷可溶级分中乙烯链段稍长
The structure and monomer sequence of the macromolecular chains of ethylene / propylene copolymer prepared by the monovanamitanium compound / mMAO catalyst system were measured by 13C NMR. The monomer reactivity ratio r1 was calculated as 7 91 ± 0 0 6, r2 = 0 135 ± 0 0 3, the product of r1r2 ≈ 1.Fineman Ross calculated monomer reactivity and 13C NMR measured values similar r1 = 7.94, r2 = 0.134, the product r1r2 = 1 0 4 .This indicates that the copolymer is stereospecific.After solvent extraction of the copolymer, the sequence distribution and the reactivity ratio of the monomers in the two fractions of ether-soluble and hexane-soluble are slightly different.Ethyl ether soluble fraction The propylene segments are slightly longer, while the ethylene segments in the hexane-soluble fraction are slightly longer