ISOSPECIFIC HOMOPOLYMERIZATION AND COPOLYMERIZATION OF STYRENE WITH ETHYLENE IN THE PRESENCE OF VCL3, ALCL3 AS CATALYST

The homopolymerization of styrene and its copolymerization with ethyle ne in the presence of a vanadium-based supported catalyst, {VCl3, 1 Al Cl3}, associated to triethylaluminium is examined. As indicated by mea ns of C-13 nuclear magnetic resoance and differential scanning calorim etry analysis, the homopolystyrenes obtained present a highly isotacti c microstructure and are semicrystalline (melting temperature 220 degr ees C). In the case of styrene/ethylene random copolymerization, the f ormation of both, polyethylene blocks and isotactic polystyrene sequen ces was identified by analysis of the crude polymer. Solubility charac teristics and structural characteristics from nuclear magnetic tesonan ce spectra of these products support the formation of copolymers with ethylene and isotactic styrene blocks rather than that of two distinct homopolymers.