TY - JOUR

T1 - Copolymerization of ethylene with 1-hexene over highly active supported Ziegler–Natta catalysts with vanadium active component but different vanadium contents

AU - Zhao, Zenghui

AU - Mikenas, Tatiana B.

AU - Guan, Peng

AU - Matsko, Mikhail A.

AU - Zakharov, Vladimir A.

AU - Wu, Wei

N1 - his work was financially supported by Petro China Petrochemical Research Institute (Daqing) and the budget project No. FWUR-2024-0037 for Boreskov Institute of Catalysis (Novosibirsk). The authors thank Nadezhda Mozgunova for catalyst preparation, Marina Vanina for GPC analysis and fractionation of polymers produced, and Igor Soshnikov for polymer analysis by means of C NMR spectroscopy.

PY - 2024/12/1

Y1 - 2024/12/1

N2 - The kinetics of copolymerization of ethylene with 1-hexene over highly active V-Mg Ziegler-Natta catalysts [VMC: VCl4/MgCl2 + Al (i-Bu)(3)] at different contents of vanadium (4 and 0.1 wt% of V) was studied. Data on copolymerization ability of these catalysts, molecular weight characteristics, and compositional homogeneity of the produced copolymers were attained. It was found that the introduction of 1-hexene led to broadening of the molecular weight distribution of copolymer (an increase in the M-w/M-n value) relative to homopolyethylene due to a decrease in the molecular weight (M-n) in the region of 1-100 kg mol(-1) without changes in the molecular weight in the region of M-n > 500 kg mol(-1) for two used VMCs catalysts. This result testified to non-uniformity of the active centers of these catalysts in the chain transfer reaction with participation of 1-hexene. Therefore, the active centers of VMCs producing high-molecular polyethylene were virtually not involved in the chain transfer reaction with 1-hexene. At the same time, these centers were more reactive in the incorporation of 1-hexene. This led to unusual distribution of butyl branches in ethylene-1-hexene copolymers produced over VMCs, namely, to an increased content of butyl branches in the high-molecular fraction of copolymers (M-w > 1000 kg mol(-1)).

AB - The kinetics of copolymerization of ethylene with 1-hexene over highly active V-Mg Ziegler-Natta catalysts [VMC: VCl4/MgCl2 + Al (i-Bu)(3)] at different contents of vanadium (4 and 0.1 wt% of V) was studied. Data on copolymerization ability of these catalysts, molecular weight characteristics, and compositional homogeneity of the produced copolymers were attained. It was found that the introduction of 1-hexene led to broadening of the molecular weight distribution of copolymer (an increase in the M-w/M-n value) relative to homopolyethylene due to a decrease in the molecular weight (M-n) in the region of 1-100 kg mol(-1) without changes in the molecular weight in the region of M-n > 500 kg mol(-1) for two used VMCs catalysts. This result testified to non-uniformity of the active centers of these catalysts in the chain transfer reaction with participation of 1-hexene. Therefore, the active centers of VMCs producing high-molecular polyethylene were virtually not involved in the chain transfer reaction with 1-hexene. At the same time, these centers were more reactive in the incorporation of 1-hexene. This led to unusual distribution of butyl branches in ethylene-1-hexene copolymers produced over VMCs, namely, to an increased content of butyl branches in the high-molecular fraction of copolymers (M-w > 1000 kg mol(-1)).

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85210394339&origin=inward&txGid=aca2fce473aa3deb4910209f574ec56e

UR - https://www.webofscience.com/wos/woscc/full-record/WOS:001364363500001

U2 - 10.1007/s13726-024-01401-x

DO - 10.1007/s13726-024-01401-x

M3 - Article

JO - Iranian Polymer Journal

JF - Iranian Polymer Journal

SN - 1026-1265

ER -