Copolymerization of Styrene and Ethylene In the Presence of Different Syndiospecific Catalysts

Some catalytic systems based on Ti or Zr compounds and methylalumoxane have been investigated with regard to their ability to promote styrene-ethylene copolymerization. 13C NMR analysis shows that the structure and the composition of the copolymerization products are dependent on the catalytic system and on the transition metal/methylalumoxane mole ratio. Polymers containing phenylethylene units bridging polyethylene sequences are generally obtained in the presence of Ti-based catalysts. In the presence of cyclopentadienyltitanium trichloride/methylalumoxane with high Al/Ti mole ratio one can obtain copolymers of ethylene and syndiotactic polystyrene. Zr-based catalyst don't promote copolymerization at all