Styrene polymerization by Ziegler-Natta catalysts based on bis(salicylaldiminate)nickel(II) complexes and methyl aluninoxane

The homopolymerization of styrene by using different catalytic systems based on bis(salicylaidiminate)nickel(II) and methylaluminoxane was investigated. In particular, the effect on catalyst activity and polymer characteristics by electron withdrawing groups located on the phenolic moiety was studied. The influence of the bulkiness of the substituents on the N-aldimine ligand was also ascertained. Finally the catalytic performances were investigated as a function of the main reaction parameters, such as temperature, Al/Ni molar ratio and duration.