The temperature dependence of the strength of adhesion between epoxy-rubber glues and steels

Abstract

We have studied the temperature dependence of the strength of adhesion between epoxy-rubber glues and steel 45 measured at a fixed loading rate. It is established that the adhesion strength σ exhibits a linear decrease with increasing temperature, predicted by the kinetic theory of fracture, only in the temperature interval between the characteristic values T t and T b. Below T t, the adhesion strength is independent of the temperature, while at T>T b, the slope of the σ(T) curve decreases with increasing temperature. Deviations from the kinetic theory predictions are explained by a change in the fracture mechanism (with tunneling transitions being involved in the fracture at low temperatures) and by variation of the parameter γ (at elevated temperatures). The values of the activation energy and activation volume of the fracture are determined.