Effect of Carbon Black Structure Aggregate Size Distribution on Properties of Reinforced Rubber

1. Broadening of the aggregate size distribution of carbon black leads to significant changes in optical properties, such as lower tinting strength and greater dissymmetry of light scattering. 2. Effects on vulcanizate properties are generally small, the most significant effect being lower hysteresis for blacks of broad distribution. 3. In moderately severe service, treadwear is unaffected by differences in breadth of aggregate size distribution sufficient to cause large changes in tinting strength. 4. Tinting strength is not a reliable criterion of treadwear quality unless carbon blacks of equal structure and breadth of ASD are compared. 5. The results of this study do not contradict earlier results on carbon black blends which show significant losses in treadwear resistance as a result of severely broadened nodule (“particle”) size and, incidentally, also aggregate size distributions.