Study On Poly(vinylidene Fluoride)/nickel Composites With Low Percolation

The preparation, electrical and thermal properties of nickel (Ni) particles filled poly(vinylidene fluoride) (PVDF) composites were discussed in this paper. The experimental density of the composites was close to that of theoretical density. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) showed that PVDF has primarily α-phase. The coefficient of thermal expansion of the composites decreased approximately 30 % compared to pure PVDF. The percolation threshold of the composite is about 5 vol% Ni, which is less than one-third of the value reported for metal filled polymer composites in the literature. The significantly lower percolation was attributed to the increased crystallinity and the better processing method which results in an easy formation of 3-dimensional network of Ni particles in the matrix, as confirmed by scanning electron microscopy (SEM). The electrical conductivity of these composites increased from 6.3×10 -13 S/cm to 2.6×10 -1 S/cm which is bet