An innovative study to evaluate fillers, part 2: Carbon black, silica and carbon black/silica blends-functional relationship between filler parameters and compound properties at constant loading

The previous study [1] evaluated rubber compound properties, at variable loading, of carbon black and silica, as a function of total volume (phi(t)) and total surface area (Sigma(s),). The results clarified the importance of volume fraction (Phi(C)) and delineated a transition point at which abrupt changes occur in compound properties. These three parameters Sigma(s), phi(t) and Phi(C) are inseparable and in conjunction totally influence compound properties. The effects of fundamental properties of fillers on compound performance properties are more noticeable at constant loading. Hence, this study should elucidate the functional relationship between fundamental properties of fillers, the added volume (V-F) and surface area (N(2)SA), with their functional relationship to rubber properties. The results show significant differences between and within grades of carbon black and silica samples from the same source. Furthermore, the theory of total volume and total surface area were utilized to create precise blends of silica/carbon black by manipulating Phi(C) in conjunction with colloidal properties of the fillers, to reduce hysteresis of a carbon black compound and also match silica compound performance properties utilizing precise blends of silica and carbon black.