Crystal transformation and thermomechanical properties of poly(vinylidene fluoride)/clay nanocomposites

The crystal transformation and thermomechanical properties of melt-intercalated poly(vinylidene fluoride) (PVDF)/clay nanocomposites are reported in this study. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to study the thermal properties of PVDF and its nanocomposites with various clay concentrations. The incorporation of clay in PVDF results in the formation of beta-form crystals of PVDF. DSC study of melting behavior suggested the presence of only alpha-phase crystals in neat PVDF and both alpha- and beta-phase crystals in the nanocomposite. This conclusion was corroborated by findings from Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). Dynamic mechanical analysis (DMA) indicated significant improvements in storage modulus over a temperature range of 20-150 degreesC. The coefficient of thermal expansion (CTE) decreases with increasing clay loading. (C) 2004 Society of Chemical Industry.