“…41 The cationic nickel(II) complexes were reported to catalyze butadiene polymerization in disperse aqueous systems with nonaqueous prepolymerization and special precautions to prevent the precatalyst from decomposing prematurely, producing PBDs with low monomer conversion and cis-1,4 content. 42,43 Furthermore, water is a toxic agent that makes catalysts inactive and causes danger in the process of olefin polymerization. Therefore, a nonaqueous solvent as the continuous phase is important in the heterogeneous polymerization of butadiene.…”