Multi-reactor system for catalyst testing in synthetic rubber solution polymerization

Synthetic rubber is an important polymeric material, with a worldwide production of around 12 million tons per annum and an annual growth rate of approximately 5 %. Modern grades with controlled microstructure are either produced by anionic or coordinative solution polymerization. For development of new grades by coordinative polymerization, catalyst systems and their operating conditions need to be optimized. For effective testing of catalyst systems in synthetic rubber solution polymerization, a multireactor setup has been developed. With this setup, a high number of polymerization runs can be performed in an effective manner in short time. The system consists of five reactors with a volume of 100 ml each. The reactors are equipped with individual stirring and a heating/cooling system. The reactors can be loaded with all needed reaction partners such as solvents, monomers, catalysts and cocatalysts. Depending on conditions, several grams of polymer can be synthesized per reaction. This sample amount allows to apply various polymer analytic methods for a profound characterization of the synthesized polymer The outlined system has been used for testing of different catalyst systems in butadiene and isoprene solution polymerization. One of the catalyst systems tested is cyclopentadienyle-titanium-trichloride / methylaluminoxan in toluene (CpTiCl3/MAO/Tol). With this catalyst system, solution polymerization of 1,3-butadiene has been studied. Focus of the study was the control of molecular weight and catalyst activity and its dependence on operating conditions.