Specific heats of rubber compounds

The specific heats of rubber compounds are very important not only for the thermodynamic calculations in various rubber processings; mixing, extrusion , calendering, and vulcanization, etc., but also for the service life of th e final products under repeated stressing conditions. In this study, the sp ecific heats of various compounding ingredients and their compounds for tir es were determined using a differential scanning calorimeter (DSC) in the t emperature range from 45 to 95 degrees C. The determined specific heats, C- p, were compared with the previous published results for natural rubber (NR ), styrene-butadiene rubber (SBR), polybutadiene rubber (BR), and isoprene- isobutyl rubber (IIR). The effects of carbon black loading and vulcanizatio n on the specific heats were investigated. The measured specific heats of t he compounds were compared with the calculated values based on the fraction al summation of the specific heat of each compounding ingredient. (C) 1999 John Wiley & Sons, Inc.