The Heat Treatment of Butyl-Carbon Black Compounds
Abstract 1. Heat enhancement effects with HAF black-GMF systems do not appear to involve a chemical bonding of the polymer to the carbon surface. The principal reasons for this view are : (a) Very similar physical properties are obtained, in the case of 50-part carbon black masterbatches, whether or not the black is present during the heat treatment. (b) When the carbon black content is increased, it is necessary to increase the quantity of GMF in order to produce a given degree of gelation. 2. With GMF, very satisfactory properties are obtained by heat-treating a highly loaded mixture and diluting this masterbatch with fresh polymer. Such a process is less sensitive to the time and temperature conditions of the heat treatment operation. 3. The application of such a procedure to Butyl-HAF black mixtures results in modulus and hysteresis properties approaching those of a conventionally mixed cold-rubber tread.