Thermal instability of electromechanical films of cellular polypropylene

An investigation has been undertaken into the thermal instability of electroactive, cellular polypropylene, in particular concentrating on the interaction between mechanical and electrical properties. A range of mechanical and electrical techniques have been applied including, dynamic mechanical analysis (DMA), thermo mechanical analysis (TMA), thermally stimulated currents (TSC) and admittance spectroscopy. Evidence is presented which indicates that the initial stages of a TSC spectrum is dominated by thickness changes in the foam. Changes in mechanical dimensions correlate well with temperature-induced changes in resonator parameters.