The polymerization of vinyl monomers has been carried out in the presence of furnace blacks using initiators such as 2,2'-azobisisobutyronitrile (AIBN) and benzoyl peroxide (Bz20Z) in nitrogen or oxygen atmosphere.
The results indicate that free radicals form by the decomposition of initiators reacting with carbon blacks to give active sites on their surface which then capture either the free radicals or the growing polymer radicals. Using the monomers with negative e values, such as styrene and vinyl acetate, a marked retardation was observed in Bz,02-initiated polymerization in the presence of furnace blacks, while a moderate inhibition was found in the polymerization initiated by AIBN. The polymerization reaction using Bz202 was found to be very sensitive to oxygen in the presence of furnace blacks and the involvement of oxygen was found to promote grafting onto the surface of carbon black by the growing polymer radicals, consequently giving polymer-grafted particles while hindering the formation of homopolymers. Furthermore, the reaction of Bz,O> with the surface of furnace blacks in oxygen atmosphere has been studied in carbon tetrachloride at 45Β°C. The resulting carbon blacks show an increase in the number of surface quinone groups with an increase in reaction time.