Mechanical Characterization and Influence of the High Temperature Shrinkage of β-PVDF Films on its Electromechanical Properties

Tensile dynamic mechanical analysis at 1 Hz was used to characterize the solid rheological properties of β-PVDF films. Both the elastic and loss moduli and the specific damping capacity were monitored against temperature, allowing the study of the effect of anisotropy upon the viscoelastic properties of the films. The temperature range covered the β- and α-relaxations. These results are compared to dielectric relaxation results in order to elucidate the electrical and mechanical contributions to the observed relaxations. Further, an important shrinking effect upon heating above 364 K has been observed, that influences the material properties. This geometrical effect has been monitored by thermal mechanical analysis. The thermal coefficients of linear expansion have been calculated, giving two different regimes for this parameter. The variations at a molecular level have been monitored by FTIR.