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The supported catalysts for propylene polymerization were prepared by milling Mg (OEt)_2 with EB (ethylbenzoate) and treating with TiCl_4 solution. When TiCl_4/(Mg(OEt)_2/EB) (mol.) ratio was increased, decrease in contents of-OEt and Ti of the catalysts was observed, while the content of EB increased. It is proved by analyses of IR, X-ray and XPS that during co-milling Mg(OEt)_2 with EB no reactions have taken place. But after treatment with TiCl_4 solution, Mg(OEt)_2 converts into MgCl_2 and EB coordinates on the resulting MgCl_2 carrier, a surface complex forms.The activity of catalysts,isotacticity and vicosimetric molecular weight of polypropylene increase with the decrease of the content of ethoxyl group. The kinetic curves of propene polymerization obtained with present catalysts system display decay curves. It is found from the triad tacticity calculated from the expanded spectra of methyl carbon region that, ethoxyl group in catalyst has an effect on the configuration of polymer chain. 相似文献
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混合外给电子体环己基甲基二甲氧基硅烷/二苯基二氯硅烷对丙烯聚合的影响 总被引:1,自引:0,他引:1
The effect CMMS (cyclohexylmethyl dimethoxysilane/DPCS (diphenyl dichloridesilane) as electron donor on the polymerization of propene was discussed. The solvent polymerization of propene was carried out in 60 ℃ at 1. 04×105 Pa. It was found that the catalyst activity has gone up by 20 per cent when CMMS/DPCS=1/3 under the given condition . The concentration of active titanium center (C) was determined with kinetic-molecular weight method. It turns out that the active titanium centers do not increase by using mixedelectron donor CMMS/DPCS as compare with CMMS as electron donor but can increase Kp by 20% In addition,average-chain length can be achieved in five minutes with CMMS/DPCS.So polymer isotacticity index does not change with the time of polymerization. 相似文献
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Copolymerization of ethylene/1-octene was carried out in toluene withvarious concentrations of comonomer in the feed using Et(Ind)_2ZrCl_2/MAO (methyl alu-minoxane) as catalyst. It was found that with the increase of 1-octene concentration in thefeed the content of 1-octene in the copolymer increases, while the density, melting point,crystallinity and intrinsic viscosity of copolymer decrease. A copolymer with very lowdensity, containing 11.5 mol% of 1-octene (VLLDPE) can be produced with this catalystsystem. The effect of temperature and zirconium aluminum mole ratio of the catalyst onthe copolymerization was also investigated. The results of ~(13)C NMR determination of thecopolymer showed that the 1-octene units in the copolymer are principally isolated. 相似文献
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