Influence of Extending Ratio on Mechanical and Piezoelectric Properties of Irradiation Cross-Linked Polypropylene Films

Abstract

Stretchable piezoelectret films may be applied in sensor skins, wearable equipment, micro-energy harvesters and so on. Irradiation cross-linked polypropylene (IXPP) foam sheets could be stretchable piezoelectrets after proper modification of microstructure and polarization. In this article, commercial IXPP foam sheets were modified by a process consisting of hot-pressing and extending and rendered piezoelectric by corona charging, and the influence of extending ratio on the stretchability and piezoelectric properties were investigated. The quasi-static piezoelectricd33coefficients up to 427 pC/N are achieved, which well retained to the strain up to 11%. The result shows that in the surface parallel plane, the Young’s module in extending and transverse direction show typical anisotropism, which retains as the secondary extending ratio increases from 0% to 110%, while in the surface normal direction, the Young’s module of the film decreases from 0.87 to 0.34 MPa. The stretchability of the modified film is significantly improved compared to which of the origin film.