Effect of hydroxylated multiwall carbon nanotubes on dielectric property of poly (vinylidene fluoride)/poly (methyl methacrylate)/hydroxylated multiwall carbon nanotubes blend

Poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA)/hydroxylated multiwall carbon nanotubes (MWNTs-OH) nanocomposites are prepared via solution blending and hot-press processing. The structure, morphology, crystallization behavior and dielectric properties of nanocomposites are studied. The results show that the crystallization of PVDF is affected by PMMA and MWNTs-OH. With the introduction of PMMA and increment of MWNTs-OH, the content of polar phase in PVDF increases. The dependence of the dielectric properties of the nanocomposites on both volume fraction of the fillers and frequency is investigated. The percolation threshold of the nanocomposite, 2.79 vol.% (volume fraction), is much lower than that of the common two phase particle-polymer composite. A dielectric constant of over 300 is observed at 10(2) Hz with 3.12 vol.% of MWNTs-OH, which is near the percolation threshold. Large enhancements of the conductivity and loss tangent are also observed near the percolation threshold. The results can be explained by the percolation theory and nanocapacitor model theory.