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

Abstract

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 0 ) 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.

Mechanical, thermal, and dielectric properties of polyvinylidene fluoride nanocomposites fabricated by introducing functional MWCNTs/barium titanate compounding dielectric nanofillers

“…According to our previous studies , [31,32] the contents of BT-OH and MWCNTs-COOH were fixed at 16 and 5 wt%, respectively. The compounding nanofillers named BT-5/ MWCNTs-1, BT-5/MWCNTs-2, BT-10/MWCNTs-1, and BT-10/MWCNTs-2 are prepared by the following steps.…”

“…Recently, PVDF nanocomposites with different MWCNTs dimensions have been prepared and investigated in our previous works. [31,32] In this paper, a facile strategy to prepare PDNs is proposed and the effects of multiscale compounding dielectric nanofillers on the microstructure and properties of PVDF based dielectric nanocomposites were reported. Four scale hybrid nanofillers BT-A/ MWCNTs-B were prepared by using two scale hydroxylated BTs (50, 100 nm) and two scale acidified multiwall carbon nanotubes (10 20 nm, 20 40 nm) as functional fillers, and then dielectric nanocomposites (BT-A/MWCNTs-B/ PVDF, where A = 5, 10 and B = 1, 2) were fabricated via direct melt-processing, and PVDF nanocomposites containing only BT-10 or MWCNTs-1 have been aols prepared by the same process for comparison.…”

Enhancing Thermal Conductivity of Polyvinylidene Fluoride Composites by Carbon Fiber: Length Effect of the Filler

“…As CFs have a higher elastic modulus, adding CFs into the PVDF matrix enhanced the storage modulus of the PVDF composites. Besides, the “physical crosslinking” interaction of the CFs between the CFs and the PVDF matrix indicated the formation of the CF network structures, which promoted the load transfer between the fillers and the matrix through the network [ 54 ]. From Figure 9 b, the loss factor peak of the PVDF/CF composites, induced by α relaxation [ 53 ], moved to higher temperatures, which represents the improved T g of the PVDF matrix after adding the CFs.…”

“…The increased T g resulted from the restriction of CFs to the segmental motions of molecular chains of the PVDF. Consequently, more energy is required for the segmental motions of the molecular chains of the PVDF [ 54 ].…”

“…The PVDF/SCF composites are more rigid than the PVDF/CF composites at the same filler loadings. In short, the higher filler loadings and shorter length gradually changed the PVDF composites from ductile to brittle modes [ 54 ].…”