Copolymerization of ethylene and 4-vinylcyclohexene by various metallocenes in the presence of Al(iBu)3/[Ph3C][B(C6F5)4]

Copolymerizations of ethylene and 4-vinylcyclohexene (VCH) were carried out with isospecific rac-1,2-ethylenebis(1-indenyl)Zr(N(CH3)2)2 [rac-(EBI)Zr(NMe2)2] and syndiospecific isopropylidene(cyclopentadienyl)(9- fluorenyl)ZrMe2 [iPr(Cp)(Flu)ZrMe2] compounds combined with Al(iBu)3/ [Ph3C][B(C6F5)4] as a cocatalyst system. VCH was regioselectively inserted into the copolymer through the vinyl double bond, leaving the endocyclic double bond unreacted. rac-(EBI)Zr(NMe2)2 catalyst showed a higher polymerization rate but lower VCH reactivity than the iPr(Cp)(Flu)ZrMe2 catalyst. The calculation of copolymerization parameters according to Kelen-Tüdös resulted in rE = 131.49 and rVCH = 0.02 for the iPr(Cp)(Flu)ZrMe2 catalyst. When [VCH] in feed was 90.5 mol-%, [VCH] in polymer was 1.88 and 8.04 mol-% for rac-(EBI)Zr(NMe2)2 and iPr(Cp)(Flu)ZrMe2 catalysts, respectively. The resulting copolymers were characterized using NMR, Raman and intrinsic viscosity measurements.