Fundamental Properties of High Structure Blacks

Abstract

Abstract The present study reports properties connected with physical and chemical surface reactivity of HAF and ISAF carbon blacks of a wide variation in structural characteristics. Methods used include determination of bound rubber and of crosslink in density in vulcanizates, adsorption of polar material from solution, adsorption and heat of adsorption of polar and nonpolar gases and vapors in the gas phase, retention of adsorbed vapors after temperature increase, electron micrography, chemical characteristics such as hydroquinone, quinone and oxygen contents and free radical activity. The results fail to show any direct connection between physical or chemical reactivity of the surface and structure. It appears that presumed manifestations of enhanced surface reactivity of high structure blacks either are nonexistent or can be explained from secondary effects not directly connected with reactivity of the particle surface. It could be shown that improved reinforcing characteristics of high structure carbon blacks are directly related to particle structure, either through particle fusion (persistent structure) or though van der Waals' type of attractive forces (transient structure).