New Methods for Estimating Dispersibility of Carbon Blacks in Rubber

Abstract Two convenient experimental methods are described for ascertaining dispersibility characteristics of carbon black. Both are based on the rate of development of optical density with dispersion or mixing time in a dilute suspension. One procedure uses polybutadiene medium and a roll mill to effect dispersion, the other chloroform and ultrasonic agitation. Correlations with conventional dispersion test results based on photomicrography are good. Advantages are precision and objectivity, not available to the same degree in photomicrograph evaluations.