Titanocenes are known to be soluble, stereospecific catalysts for the polymerisation of prochiral olefins such as styrene. In this work we shall describe the relations between polystyrene cracteristics and the structure of the catalyst precursor, namely those of the family (RCp)2TiCl2 (R = H, ethyl, iso-propyl, n-propyl, sec-butyl, n-butyl, iso-amyl e ciclohexyl). All catalysts were found to be active for the production of polystyrene at temperatures above zero degrees centigrade. The syndiotacticity of the polymers were found to be dependent on the side chain at the aromatic rings of the titanocene, and onthe temperature of polymerisation. The relationship between steric and electronic factors within the catalyst precursors and the polymerisation products shall be presented and discussed.
Polystyrene; titanocenes; Ziegler-Natta catalysis; homogeneous catalysis; steric and electronic effects
