THE INFLUENCE OF AGING AND POLYMERIZATION CONDITIONS ON THE POLYMERIZATION OF BUTADIENE USING A NEODYMIUM CATALYST SYSTEM

The homopolymerization of butadiene in the presence of a rare earth-co ntaining catalyst system was examined at 60 degrees C. The catalyst sy stem consists of neodymium octanoate, diethylaluminium sesquichloride and triisobutyl aluminium in n-heptane. This catalyst shows high activ ity also at low polymerization temperature and yields polymers with a cis-1,4 content of nearly 99%. The catalyst ageing and the polymerizat ion conditions were varied and the behaviour of molar mass distributio n, conversion and microstructure of polymers is illustrated. Attention is focussed on molar mass distribution of cis-l,4-polybutadiene sampl es which can be unimodal or bimodal in dependence on the preparation c onditions.