Copolymerization of norbornene with ethylene: a high-resolution liquid NMR, DSC and solid state NMR study

Abstract

In this paper, we report the monomer reactivity on the copolymerization of norbornene and ethylene. The reactivity ratios for ethylene (M-1) and norbornene (M-2) are 18.5 and 0.035, respectively. Different copolymerization conditions can produce COC with different microstructures. A C-13 NMR shift assignment in pentad sequences in copolymers has been obtained. More isolated polynorbornene or a micro-block length can be obtained using a low Zr/Al catalyst/co-catalyst ratio and at a lower NB/ethylene feed ratio. The T-1p(C) decay curve shows two component decays in all resonance peaks. These two component decays come from different norbornene microstructures, while the block and alternative have similar T-1p(C) values.