Effect of Carbon Black on Heat Build-up and Energy Dissipation in Rubber Materials

Abstract

The heat build-up and energy dissipation of carbon black reinforced natural rub-ber compounds are studied using a rebound resilience tester, Goodrich flexometer and a Coesfeld heat build-up analyser. Natural rubber compounds containing eight different carbon blacks at 50 parts per hundred (phr) were studied. The car-bon blacks varied widely in their structure and surface area properties allowing quantitative correlations to the heat build-up and rebound resilience measure-ments to be extracted from their colloidal properties. The results show the nature of deformation dictates different levels of influence of the carbon black proper-ties. Carbon black surface area dominates in influencing the heat build-up and energy dissipation in the Goodrich flexometer, Coesfeld heat build-up analyser and rebound resilience measurements. The Goodrich flexometer heat build-up measurement, however, is the only experimental measurement where carbon black structure places a significant role in determining the heat build-up. The dif-ferences in the levels of influence of carbon black colloidal properties can be un-derstood when the deformation index concept is applied to the experimental re-sults. Goodrich flexometer measurements are predominantly strain controlled measurements while rebound resilience and Coesfeld heat build-up are a complex combination of strain and energy-controlled deformations. Understanding the type of deformation that dominates in various heat build-up and energy dissipa-tion tests and how carbon black properties affect the results of the tests are of practical importance. It enables the heat build-up and energy dissipation tests that closely represent the type of deformation that will be predominant in field appli-cations to be selected during compound development and characterisation. It also gives an understanding of how carbon black properties can be leveraged to opti-mize desired heat build-up and energy dissipation properties depending on the type of deformation during compound development.