钛系载体催化剂乙丙橡胶的合成及其性能的研究

SYNTHESIS OF ETHYLENE-PROPYLENE RUBBER WITH SUPPORTED Ti-CATALYST AND CHAIN STRUCTURE OF THE COPOLYMER

采用反应法制备的 MgCl_2/EtOH/AlEt_2Cl/TiCl_4/给电子添加剂体系为载体催化剂,以Al(i-Bu)_3为助催化剂,对乙烯-丙烯共聚合进行了研究。在PCl_3、C_6H_5COOEt和P(C_6H_5)_3中,以给电子能力较强的 P(C_6H_5)_3作添加剂,催化剂的效率可达到 2.4×10~5g 胶/(g Ti·h),EPM的不溶物含量<1％。用DSC、X光衍射、IR和^(13)C-NMR 等方法对所得 EPM 的分析表明,EPM 中难于溶解的长乙烯链段是产生不溶物的主要原因;钛系载体催化剂对丙烯的定向性很高,与钒系 EPM 相比,长丙烯链段含量和丙烯链段的规整性较高。乙烯和丙烯在本催化体系中的竞聚率分别为4.05和0.414。本体系所合成的 EPM,除永久变形外,其他性能已达到或接近钒系EPM的指标。

The copolymerization of ethylene and propylene was studied by using MgCl2-EtOH-AlEt2Cl-TiCl4-electron donor as supported catalyst system which was prepared by the reaction method, and using Al ( i-Bu ) 3 as co-catalyst. It was found that the addition of electron donor to the catalyst system could increase the catalyst efficiency to 2.4 × 105 g polymer/ (g Ti·h), and inhibit the formation of solvent insoluble matter <1%. Ethylene-propylene copolymer ( EPM ) was examined by DSC, X-ray, IR and 13C-NMR method. It was also found that the soluble part of EPM prepared supported Ti-catalyst characterized by a higher content long polypropylene segment, as compared with that of the V-catalyzed EPMs. The absence of 'head to head' and 'tail to tail' linkage of propylene molecules in the EPM imparted to the propylene segments a higher stereoregularity. The reactivity ratio of ethylene and propylene in Ti-catalyst system was determined to be:rE=4.05, rE = 0.414. All the measured physical properties matched with those of V-catalyzed EPM with the exception of permanent set.