Dual-site hybrid catalysts for production of linear low-density polyethylene

Седов, И. В.; Russiyan, L. N.; Блинова, Л. Н.; Davydova, G. I.; Кнерельман, Е. И.; Васильева, Л. С.; Zlobinsky, Yu I.

doi:10.1007/s10965-014-0583-4

Cited by 4 publications

(1 citation statement)

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“…One of the main strategies used for the improvement of polyolefin catalysts, which is still being investigated at the laboratory scale, is the use of a combination of different types of catalysts during polymerization. Catalyst alloys, hybrid catalysts and multi‐catalyst systems are commonly used in this respect . In these systems, each of the catalysts produces polymers with different properties, and therefore the final polymer is a blend of two or more kinds of polymers.…”

Section: Introductionmentioning

confidence: 99%

Single and binary catalyst systems based on nickel and palladium in polymerization of ethylene

Kimiaghalam

Nasr‐Isfahani

Zohuri

et al. 2017

Applied Organom Chemis

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The catalyst (N,N‐bis(2,6‐dibenzhydryl‐4‐ethoxyphenyl)butane‐2,3‐diimine)nickel dibromide, a late transition metal catalyst, was prepared and used in ethylene polymerization. The effects of reaction parameters such as polymerization temperature, co‐catalyst to catalyst molar ratio and monomer pressure on the polymerization were investigated. The α‐diimine nickel‐based catalyst was demonstrated to be thermally robust at a temperature as high as 90 °C. The highest activity of the catalyst (494 kg polyethylene (mol cat)−1 h−1) was obtained at [Al]/[Ni] = 600:1, temperature of 90 °C and pressure of 5 bar. In addition, the performance of a binary catalyst using nickel‐ and palladium‐based complexes was compared with that of the corresponding individual catalytic systems in ethylene polymerization. In a study of the catalyst systems, the average molecular weight and molecular weight distribution for the binary polymerization were between those for the individual catalytic polymerizations; however, the binary catalyst activity was lower than that of the two individual ones. The obtained polyethylenes had high molecular weights in the region of 105 g mol−1. Gel permeation chromatography analysis showed a narrow molecular weight distribution of 1.44 for the nickel‐based catalyst and 1.61 for the binary catalyst system. The branching density of the polyethylenes generated using the binary catalytic system (30 branches/1000 C) was lower than that generated using the nickel‐based catalyst (51/1000 C). X‐ray diffraction study of the polymer chains showed higher crystallinity with lower branching of the polymer obtained. Also Fourier transform infrared spectra confirmed that all obtained polymers were low‐density polyethylene.

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Section: Introductionmentioning

confidence: 99%