Emulsion polymerization of butadiene with a cationic nickel catalyst

Polymer dispersions are produced on a large scale, e.g. for coatings and paints. They are usually manufactured by free-radical emulsion polymerization. One of the major monomers is butadiene (BD), which is readily available from cracking of hydrocarbon feedstocks.The versatility of butadiene insertion (1,2, 1,4-trans, or 1,4-cis) in prinicple allows for the synthesis of polymers with various and controlled microstructures and therefore very different materials. However, by freeradical polymerization polybutadiene (PBD) dispersions with only a very limited range of microstructures are accessible. BD is typically incorporated as 14 % cis-1,4; 69 % trans-1,4 and 17 % 1,2- (vinyl) units. Coordination polymerization can allow for a much broader microstructure control. Cationic nickel(II) complexes are known to polymerize butadiene in organic solvents. 1,2-incorporation is low and the cis/trans ratio depends on the nature of the coordinating ligand and the counterion