Structural, rheological, and electrical properties of suspensions of carbon black with different oxidation degrees in polar and apolar dielectric dispersion media

Abstract

The structural, rheological, and electrical characteristics of carbon black (CB) suspensions with different oxidation degrees of particles have been studied in polar and apolar media. The structural characteristics have been determined for individual particles and particle aggregates of CB in a powdered form and in dispersion media. The yield stresses of CB suspensions in Vaseline oil (VO) and castor oil (CO) increase with the oxidation degree of particle surface; however, at the same oxidation degree of particles, the yield stress of suspensions in VO is, as a rule, lower than that in CO. In all suspensions, the calculated sizes of secondary aggregates decrease with a rise in the CB oxidation degree; however, at the same oxidation degree, the secondary aggregates in suspensions in VO are, as a rule, larger than those in suspensions in CO. Possible mechanisms of the electrical conductivity of the suspensions have been considered both at rest and under different regimes of dynamic actions. An interpretation has been proposed for the appearance and shifts of dilatantcy peaks for CB suspensions as depending on the oxidation degree of CB particle surface and the nature of a dispersion medium.