Material PropertiesDetermination of thermal properties of pyroelectric polymers, copolymers and blends by the laser flash technique

Precise determination of polymer thermal properties is of fundamental importance in many engineering processes and design. Specifically, thermal diffusivity is an important property in non-steady-state situations, as for instance during heating and cooling of polymers. Knowledge of this property and its variation with temperature is crucial in the description and analysis of extrusion processes. Particularly, pyroelectric properties, exhibited by some polymers, are strongly dependent on the thermal diffusivity of the material. In this investigation, thermal diffusivity of poly(vinylidene fluoride) (PVDF), of poly vinylidene fluoride-trifluoroethylene copolymers P(VDF-TrFE) and of PVDF/P(VDF-TrFE) blends, all pyro and piezoelectric materials, was determined by the laser flash technique at 25 and 100 °C. At 25 °C, sample density and specific heat were also determined and, using the thermal diffusivity values, thermal conductivities were calculated for this temperature. For PVDF, thermal diffusivity was also determined in the range between 25 and 203 °C. For the first time, this property has been determined for PVDF above the melt temperature.