Studies on α to β phase transformations in mechanically deformed PVDF films

Abstract

PVDF cast films were drawn at different temperatures to different draw ratios at constant draw rate to understand the mechanism of to ß phase transformation during mechanical deformation. WAXD and FTIR studies were carried out to determine the formation and content of ß phase in the drawn films. Lower stretch temperatures gave higher fractions of ß phase. The cast PVDF films were also drawn at suitable temperatures below the PVDF ambient melting point to the draw ratio of 6.4. The highest fraction of ß phase obtained in these ultra drawn films was 0.98. SALS studies carried out for films at different stretch ratios show the change in spherulitic structure with the stretching parameters and give information for the understanding of phase transformation during stretching of PVDF films.