Syndiotactic 1,2-polybutadiene synthesis in an aqueous medium utilizing N,N-dibutylformamide as a modifier

Pure syndiotactic 1,2-polybutadiene is a thermoplastic resin which has double bonds attached in an alternating fashion to its polymeric backbone. Films, fibers and molded articles can be made utilizing syndiotactic 1,2-polybutadiene. It can also be blended into rubbers and cocured therewith. Syndiotactic 1,2-polybutadiene can be made by solution, emulsion or suspension polymerization. It typically has a melting point which is within the range of about 195 degrees C. to about 215 degrees C. However, it is often desirable for the syndiotactic 1,2-polybutadiene to have a melting point of less than about 195 degrees C. This invention discloses a process for preparing syndiotactic 1,2-polybutadiene having a melting point of less than about 195 degrees C. which comprises: polymerizing 1,3-butadiene monomer in an aqueous medium in the presence of (1) a catalyst composition which is made by reacting (a) at least one cobalt compound (b) at least one organoaluminum compound, and (c) at least one conjugated diene; (2) carbon disulfide; and (3) N,N-dibutylformamide. This invention further discloses that catalyst emulsion compositions made utilizing amino acid soaps, such as sodium lauroyl sarcosinate, have much better stability than those made with standard surfactants.