Effect of temperature on the mechanical behavior of pvc foams

Abstract

Experiments were conducted to characterize the mechanical behavior of Divinycell PVC foams over a wide range of environmental temperatures, from −60 to +80°C. Transversely isotropic properties of the foams, including modulus, strength, and ductility, were found to vary with temperatures between the ductile-to-brittle transition temperature (−60 to −50°C) and just under the glass transition temperature (95 to 100°C). The elastic modulus and yield strength decreased linearly as the temperature increased from −60 to +80°C. Compressive strength also decreased steadily with increasing temperature over the entire temperature range. In contrast, tensile and shear strengths only showed a significant decrease in values as the temperature rose above 23°C (room temperature). Below 23°C, there was a minor change in tensile and shear strengths. Tensile and shear ductility decreased sharply as the temperature decreased from +80°C to −40°C and stabilized between −60 and −40°C, which is close to the ductile-to-brittle transition region. Fractography of the tensile and shear fracture surfaces confirmed brittle fracture at −60°C and ductile tearing at +60°C. Equations were derived to predict modulus, yield strength, compressive, tensile and shear strengths, and ductility at any temperature in terms of room temperature values.