Facile preparation and properties of polyvinylidene fluoride dielectric nanocomposites via phase morphology control and incorporation of multiwalled carbon nanotubes conductive fillers

A novel PVDF dielectric nanocomposite was achieved by controlling phase morphology and incorporating conductive fillers simultaneously, and the mechanical, thermal, dielectric properties of the resultant dielectric nanocomposites were investigated. Mechanical analysis showed that incorporation of modified MWCNTs (MWCNTs-COOH) in the PVDF nanocomposites resulted in significant improvements on the tensile strength (T_s) and elasticity modulus (E_m). When the filler content was 12 wt%, the T_s of MWCNTs-COOH/PVDF could reach 64.6 MPa. XRD test showed that the addition of MWCNTs-COOH and MWCNTs promoted the formation of β-phase of PVDF. DMA analysis showed that the glass-transition temperature of the PVDF nanocomposites slightly increases on loading of original MWCNTs and this effect was more pronounced on loading MWCNTs-COOH. The dielectric property analysis showed that the original MWCNTs were more likely to form local conductive networks in the PVDF matrix, promoting the electron displacement polarization, and improving the dielectric constant. When the contents of MWCNTs was 12 wt%, the percolation threshold was obtained and the dielectric constant (ε′) reached 286, which was 36 times of pure PVDF. Our work provides a simple way to fabricate polymer blends with excellent dielectric performances, good mechanical properties as well as good processing capability but low cost. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48463.