BUTADIENE POLYMERIZATION USING BINARY NEODYMIUM-BASED CATALYST SYSTEMS - THE EFFECT OF CATALYST PREPARATION

The influence of preparation conditions on the activity of NdCl3.3TBP- TIBA catalysts for the polmerisation of butadiene have been investigat ed. The highest catalysts activities and resulting polymer molecular m asses have been found where the catalyst is ''preformed'' in the prese nce of precise and small amounts of butadiene (molar ratio [Butadiene] /[Nd] = 2) and is aged for 1 hr at 20 degrees C. Polybutadienes with a 1,4-cis content of 98-99% are readily achieved irrespective of the me thod of catalyst preparation. The enhanced reactivity of the ''preform ed'' catalyst is explained in terms of a stable pi-allylic complex inv olving the butadiene unit. (C) 1997 Elsevier Science Ltd.