Cationic grafting from carbon black. II. Polymerization of styrene initiated by CO+ClO group on the surface of carbon black

The cationic grafting of polystyrene initiated by carbon black containing the CO⁺ClO group was investigated. The introduction of CO⁺ClO groups onto a carbon black surface was achieved by the reaction of AgClO₄ with carbon black that contained a COCI group. The latter was introduced by the reaction of carboxyl groups with SOCl₂. It was found that polystyrene chains could be grown from CO⁺ClO groups on the surface of carbon black. Moreover, polystyrene was effectively grafted from carbon black: the grafting ratio at 20°C increased to 58% as conversion increased. Furthermore, the grafting ratio and molecular weight of ungrafted polystyrene decreased with an increase in polymerization temperature. These results were explained by the fact that the increasing temperature of the polymerization caused an increase in the rate of chain transfer reaction of the growing polymer chain to the monomer. The carbon black obtained from the reaction produced a stable colloidal dispersion in a good solvent for polystyrene.