A novel imido-modified SiO2-supported Ti/Mg Ziegler-Natta catalyst for ethylene and ethylene/1-hexene polymerization is investigated. The catalyst is prepared by modification of (SiO2/MgO/MgCl2)TiClx Ziegler-Natta catalysts via supporting vanadium species followed by reaction with p-tolyl isocyanate as imido agents, to get the merits from both the SiO2-supported imido vanadium catalyst and the ...

This article reviews the surface science of the heterogeneous olefin polymerization catalysts. The specific focus is on how to prepare and characterize stereochemically specific heterogeneous model catalysts for the Ziegler-Natta polymerization. Under clean, ultra-high vacuum conditions, low-energy electron irradiation during the chemical vapor deposition of model Ziegler-Natta catalysts can be...

Heterogeneous Ziegler-Natta and homogeneous metallocene catalysts exhibit greatly different active sitenature in olefin polymerization. In our previous study, it was reported that MgCl2-supported titanocenecatalysts can generate both Ziegler-Natta-type and metallocene-type active sites according to the type of activators.The dual active site nature of the supported titanocene catalysts was furt...

heterogeneous ziegler-natta and homogeneous metallocene catalysts exhibit greatly different active sitenature in olefin polymerization. in our previous study, it was reported that mgcl2-supported titanocenecatalysts can generate both ziegler-natta-type and metallocene-type active sites according to the type of activators.the dual active site nature of the supported titanocene catalysts was furt...

the effects of temperature, time and the strategy of prepolymerization were studied on the morphology of polypropylene particles. propylene polymerization was carried out in slurry phase using 4th generation of ziegler-natta catalyst, cyclohexylmethyl dimethoxysilane as external electron donor, and triethyl aluminum as co-catalyst. prepolymerizations were carried out based on two strategies: is...

a new model based on a combination of the polymeric multigrain and multilayer models has been developed to predict the polymerization rate, particle growth, morphology, effective parameters on broadening of the molecular weight distribution, number and weight average of the molecular weight, isotacticity index and bulk density of polymer. mathematical correlations and the kinetics used in this ...

full factorial experimental design (23) for the evaluation of slurry ethylene polymerization in the presence of an industrial ticl4/mgcl2 ziegler-natta catalyst was employed. the following parameters were used as independentvariables: al/ti molar ratio, reaction temperature and hydrogen partial pressure. the total polymerization pressure was 9 bar. catalyst activity, mfi (melt flow index) and m...

mg(oet)2 with spherical morphology is one of the most important precursors for the preparation of industrialziegler-natta catalysts. in the present article, morphology evolution of mg(oet)2 particles is studied in the courseof the synthesis. the morphology of mg(oet)2 particles is observed throughout the process by sem. the resultsshow that mg(oet)2 particles are formed through i) seed generati...

Understanding the kinetics of olefin polymerization with Ziegler-Natta and related catalysts means identifying the main kinetic parameters such as k(p) and concentration of active sites. The high-pressure quenched-flow technique could be an absolute method for counting active sites and for activation studies of molecular catalysts. A kinetic study of metallocene catalysts and a phenoxy-imine ti...