Effect of e-Value of Vinyl Monomers on the Radical Graft Polymerization from Carbon Black Surface

Abstract

The effect of e-value of vinyl monomers on the radical graft polymerization initiated by azo or peroxyester groups introduced onto carbon black surface was investigated. In the presence of carbon black having azo-groups (CB-Azo), the polymerization of vinyl monomers with positive e-value, such as methyl methacrylate, was initiated to give polymer-grafted carbon black. Although the polymerization of vinyl monomers with negative e-value, such as styrene, initiated by CB-Azo was retarded, the corresponding polymer was also grafted onto the surface. On the other hand, carbon black having peroxyester groups (CB-POE) was capable of initiating the polymerization of vinyl monomers with positive e-value, but incapable of that with negative e-value. Therefore, vinyl polymers with negative e-value were unable to graft onto carbon black by use of CB-POE. A similar tendency was observed in the polymerization initiated by 4, 4'-azobis (4-cyanopentanoic acid) or t-butyl peroxybenzoate, as a model compound of initiating groups on the carbon black surface, in the presence of untreated carbon black: the polymerization of styrene initiated by t-butyl peroxybenzoate was remarkably retarded by carbon black. These results indicate that the radical graft polymerization initiated by initiating groups introduced onto carbon black surface is affected by e-value of vinyl monomers.