载体型钛系催化剂的丙烯与乙烯共聚合研究

以载体型钛系齐格勒-纳塔催化剂进行了丙烯和乙烯无规共聚合的研究。对聚合温度、铝钛摩尔比、给电子体浓度和加氢等行为作了考察。共聚合速度和共聚物的比浓粘度呈规律性变化。用~(13)C-NMR和DSC测定了共聚物的组成、序列分布、熔点和结晶度.结果表明,在共聚合反应速度曲线上,在丙烯和乙烯分别为10mol％组成处,出现两个最大值。随共聚物中乙烯含量增加(2—10mol％),其熔点和结晶度降低,DSC峰变低、变宽,在乙烯含量达10mol％处出现双峰(128/116℃)反映出无规共聚链出现不同的序列分布。

STUDY ON THE COPOLYMERIZATION OF PROPYLENE AND ETHYLENE WITH A SUPPORTED TITANIUM CONTAINED CATALYST

The random copolymerization of propylene and ethylene with a supported titanium contained Ziegler-Natta catalyst has been studied. The effects of temperature, Al/Ti molar ratio, concentration of electron donor and hydrogen on the copolymerization reaction were described. The regular variations of the copolymerization rate and the viscosity of copolymer were discussed. The composition, sequence of copolymer were measured by 13C-NMR. Two maxima of the curve of copolymerization rate vs feed ratio of comonomers at 10 mol % of propylene and ethylene respectively have been observed. DSC curves display that both of melting temperature and crystallinity of the copolymer decrease with increasing of the molar fraction of ethylene and the peak shape becomes lower and broader in the range of 0-10 mol% of ethylene ratio at 128/116℃, which are attributed to the formation of two different sequences in the random copolymer chains.