Specific heats of rubber compounds

Abstract

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 the final products under repeated stressing conditions. In this study, the specific heats of various compounding ingredients and their compounds for tires were determined using a differential scanning calorimeter (DSC) in the temperature 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 vulcanization on the specific heats were investigated. The measured specific heats of the compounds were compared with the calculated values based on the fractional summation of the specific heat of each compounding ingredient. (C) 1999 John Wiley & Sons, Inc.