Effect of Density and Ambient Temperature on Coefficient of Thermal Conductivity of Heat-Insulated EPS and PU Materials for Food Packaging

Abstract

Coefficient of thermal conductivity is an important index of performance evaluation of heat-insulated material. In order to provide theoretical reference basis for the selection of heat-insulated materials, we test the coefficient of thermal conductivity of polystyrene foamed plastic (EPS) and rigid polyurethane foam plastic (PU) in different densities at different ambient temperatures, and then determine the effect of material density and ambient temperature on the coefficient of thermal conductivity of food insulation packaging materials. According to the national standard GB/T10297-1998(Test method for thermal conductivity of nonmetal solid materials by hot-wire method), we test the coefficient of thermal conductivity of samples in different densities at different ambient temperatures. The result shows that at the same temperature, the coefficient of thermal conductivity increases first and then decrease with the increase of density. In the same density, the coefficient of thermal conductivity increases with the increase of ambient temperature.