Study On The Ziegler-natta Catalyst For 1-butene Polymerization

Polyl-butene(PB) for its excellent creep resistance and environmental stress cracking resistance is widely accpected by people.However, the raw materials for producing polyl-butene products at home mainly depend on importing at the present time, this is because catalysts and processes of preparing high-performance polyl-butene are scarce. Therefore, the research and development of new polyl-butene catalyst is an important method to break away from foreign technology blockade to our country. Ziegler-Natta catalyst holds an important position in the synthesis of polyolefins.The electron donors of Ziegler-Natta catalyst play a pivotal role.In this study, a new type of novel MgCl2 supported titanium Ziegler-Natta catalyst of 9,9-bis(methoxymethyl) fluorene (BMMF) as the internal electron donor was synthesized, and a variety of external electron donor coupled with the catalysts of 9,9-bis(methoxymethyl)fluorene and n-butyl phthalate (DNBP) as an internal electron donor were used in the polymerization of 1-butene for finding out a kinds of catalyst which could get a high catalytic activity and high-performance polyl-butene.In this study, three kinds of polyl-butene catalysts (without internal electron donor, DNBP and BMMF respectively as the internal electron donors) were prepared.The effects of polymerization conditions such as the loading of catalyst, Al/Ti molar ratio and polymerization temperature, external electron donor type and loading on the catalytic activity and product properties were investigated.And isotacticity and molecular weight of polyl-butene were measured by soxhlet extraction device and ubbelohde viscometer.Three catalyst systems (TiCl4/MgCl2, TiCl4/MgCl2/DNBP and TiCl4/MgCl2/BMMF) were compared and investigated the performance on polymerization of 1-butene. The polymerization results indicated that polyl-butene catalyst of BMMF as internal electron donor showed higher catalytic activity, when the loading of catalyst was 5mg, Al/Ti molar ratio was 400 and polymerization temperature was 20℃,the catalyst activity was up to 2856gPB/(gcat·h) about three times other two kinds of catalysts, when the dicyclopentyldimethoxysilane (DCPDMS)/Ti mole ratio was 10,the isotacticity of polyl-butene that TiCl4/MgCl2/DNBP catalyst prepared reached 92.65%.