POLYMERIZATION OF 1,3 BUTADIENE IN PRESENCE OF STYRENE USING NEODYMIUM VERSATATE CATALYST AND SYNTHESIS OF ABS BY "IN SITU BULK" PROCESS

butadiene was selectively polymerized in presence of styrene as solvent using a ternary catalyst system constituted by: neodymium versatate/diisobutylaluminium hydride/ethylaluminium sesquichloride (NdV/DIBAH/EASC). Different molar ratios Al/Nd and Cl/Nd were studied, as well as the styrene concentration, the aging time of the catalyst system and the addition order of the reactants. High butadiene conversions were achieved resulting in polybutadienes with a high content of the cis-1,4 isomer (> 95%, calculated by NMR). Styrene polymerized in low proportion reaching a maximum of 15 %-wt in the obtained rubbers (polybutadiene-co-polystyrene). After that, an appropriate amount of acrylonitrile was added to the reaction medium (rubber/styrene) and the polymerization reactions were carried out by an in situ bulk free radicals process to produce poly(acrylonitrile-butadiene-styrene) (ABS) resins which were properly characterized.