Correlation of piezoelectric effect and TSC in stretched polystyrene-acrylonitrile films

The piezoelectric coefficient d₃₁ of stretched SAN (polystyrene-co-acrylonitrile) films has been measured under different poling and stretching conditions. The maximum average value of d₃₁ has been found to be 3.85 pC/N for 2.5× stretched films, corona poled at field E_P≃50 MV/m, and poling temperature T_P=85°C. The TSC (thermally stimulated current) experiments were performed to obtain the contribution of the polarization to the piezoelectric activity. The shrinkage effect and the TSC results are correlated to elucidate the molecular relaxation processes. The elastic modulus, crystallinity and polarization parameters are correlated to the piezoelectricity. The contributions of the dimensional and the local field effects to the piezoelectric activity in SAN are discussed