Molecular structure of polyethylene produced with supported vanadium-magnesium catalyst

• Published in: Macromolecular chemistry and physics Vol. 200; no. 6; pp. 1434 - 1438
• Main Authors: Echevskaya, Lyudmila G., Zakharov, Vladimir A., Golovin, Anatolii V., Mikenas, Tatyana B.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag GmbH 01-06-1999; WILEY‐VCH Verlag GmbH
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/(SICI)1521-3935(19990601)200:6<1434::AID-MACP1434>3.0.CO;2-4

The molecular structure of polyethylene (PE) produced with supported titanium‐magnesium (TMC) and vanadium‐magnesium (VMC) catalysts has been studied by means of IR and 13C NMR spectroscopic methods. It has been shown that PE produced with VMC in the presence of hydrogen differs by a lower content of double bonds and higher branching compared with PE obtained with TMC. Furthermore, branching is observed both in the heptane‐soluble low molecular weight fraction and in the high molecular weight fraction of PE. 13C NMR studies of the low molecular weight fraction of PE showed the presence of methyl branches. Intramolecular isomerization of the growing polymer chains involving hydrogen seems to be a possible reason for the formation of methyl branches.