Polymerization of norbornene using novel palladium carboxylate/boron trifluoride etherate catalyst system

Abstract

The vinyl polymerization of norbornene with Pd(carboxylate)(2)/BF3OEt2 catalyst system has been investigated by varying the molar cocatalyst/metal ratio, the norbornene/metal ratio, the metal concentration and the reaction temperature. The effects on the catalyst activity were explained on the basis of complexation equilibrium for the active homogeneous complex. A "particular" activity of 154 100 kg NB per mole Pd for an hour has been achieved at B/Pd = 25 and 25 degrees C. The molecular weights M-w from 77 700 to 293 800 g/mol and glass transition temperatures T-g from 240 to 262 degrees C were observed for the representative samples of polynorbornene. The molar mass distribution indicates a single-site, highly homogeneous character of the active catalyst species. Catalytic activity and polymer molecular weight can be controlled by varying the reaction parameters over a wide range. NMR and IR spectroscopic studies of the polymer showed 2,3-enchained repeating units of polymer backbone with low diisotacticity. The simplicity of catalyst system composition might be of industrial importance. (c) 2006 Elsevier Ltd. All rights reserved.