Use of ESR to Investigate Formation of Free Radicals on Compounding Rubbers with Carbon Blacks

Abstract

The problem of rubber reinforcement is of great importance in rubber technology. Free radicals formed during mastication play an important role in the reinforcement of the rubber-filler system. The reinforcement of rubber systems is usually explained in terms of chemical interactions between rubber and filler; however, there are also opinions that the interactions are physical in nature. So far, the mechanism of reinforcement is an open question. Undoubtedly, reinforcement is influenced by free radicals formed during mastication and the physicochemical state of the surface of active fillers. The formation of free radicals during plasticization of rubbers has been already reported. Investigations by an ESR technique of free-radical formation during compounding of rubbers with various carbon blacks are described in the present paper.