EFFECT OF CARBON-BLACK LOADING AND CROSS-LINK DENSITY ON THE HEAT BUILDUP IN ELASTOMERS

The mechanical properties of elastomers are greatly affected by the addition of carbon black. The elastic and viscoelastic properties are affected too; the quasi-static moduli and the complex dynamic moduli are increased, hysteresis increases, etc. Based on previous experimental findings, certain simplifying assumptions regarding the effects of reinforcing fillers and the crosslink density on the dynamic properties of elastomers can be made. It has been shown that it is possible to predict the viscoelastic response of elastomers and elastomeric engineering components under both load- and position-control conditions if one assumes: a) that the modulus of the materials increases with the strain amplification factor as given by the Guth and Gold equation, b) that the occluded rubber is taken into account when using this equation, and c) that the energy loss per cycle and unit volume of material is increasing with the square of the strain-amplification factor. The model is obviously too oversimplified for qualitative predictions. But it still gives good qualitative indications regarding the heat-generation rate in structures made from two elastomers having different filler loadings or for imperfectly mixed compounds.