Polymerization of 1,3-Butadiene usingAluminoxane-Based Nd-CarboxylateCatalysts

Abstract

The ternary neodymium-based catalyst for the polymerization of 1,3-butadiene, Nd(versatate)3/AliBu2H/tert-butyl chloride, has been examined with respect to the effects of replacing the alkylaluminium hydride with aluminoxane, namely methylaluminoxane (MAO) and tetraisobutyldialuminoxane (TIBAO). Catalysts based on MAO were found to be active even in the absence of a halogen source, whereas TIBAO catalysts were active only when a halogen was present (catalyst activity TIBAO > MAO). Using catalysts prepared both preformed and in situ, the effects of polymerization temperature, solvent and MAO level on catalyst activity and the characteristics of the final polymer are discussed. Polybutadiene cis contents and molecular weights were higher with MAO-based catalysts than with AliBu2H-based catalysts. Cis contents were also higher when MAO catalysts containing tert-butyl chloride were used, compared to their non-chloride counterparts.