Abstract
At first, we assume that carbon black dispersion state in rubber vulcanizates changes from isolated to aggregate at the critical filler quantity, and prove the validity of this hypothesis from the simple calculation for thermodynamic model. Next we make clear that this model is enough to explain the various experimental data qualitatively, for example, the relationships between carbon black quantity and entropic or energetic element of tensile stress, tensile strength and ultimate elongation. In addition, we pressume that this transition occurs at the same apparent volume fraction of fillers containing the dense structure (so-called C-phase) around carbon black particles, and prove this assumption experimentally for several kinds of carbonblack.
