A simultaneous characterization of thermal conductivity and diffusivity of polymer materials by a periodic method

A periodic method is used to determine simultaneously both thermal conductivity and diffusivity of various polymer materials at room temperature. The sample is placed between two metallic plates and temperature modulation is applied on the front side of one of the metallic plates. The temperature at the front and rear sides of both plates is measured and the experimental transfer function is calculated. The theoretical thermal heat transfer function is calculated by the quadrupole method. Thermal conductivity and diffusivity are simultaneously identified from both real and imaginary parts of the experimental transfer function. The thermophysical parameters of several polymer samples (PTFE, PVDF and PA11) with different thicknesses (respectively, 5 mm, 2 mm and 300 mum) were studied and compared with values from the literature. The values identified for the thermal parameters are in good agreement with values from the literature for PTFE and PVDF samples; however, we show that the method reaches its limit for the thinner PA11 sample, owing to inadequacy of the thermal model.