Electrical and dynamic mechanical behavior of BaTiO3/VGCF/LDPE composite

Abstract

The electrical and dynamic mechanical behavior of barium titanate (BaTiO 3 )/vaporgrown carbon fiber (VGCF)/Low Density Polyethylene (LDPE) composites has been studied. The measurement of electrical conductivity exhibits a lower percolation threshold and a more distinct two-stage percolation region, especially with a wide plateau between the two stages, for BaTiO 3 /VGCF /LDPE composites compared to the two-component system of VGCF /LDPE. This can be attributed to increase of the effective concentration of VGCF and the obstruction of BaTiO 3 particles on VGCF networks. The dynamic mechanical spectra of BaTiO 3 / VGCF /LDPE composites present a distinctive α relaxation region with its peak value nearly remaining constant at its high temperature side in contrast to the abrupt decrease of LDPE. Moreover, the loss factor in the α relaxation region reaches its largest value for the composite of 8 vol% VGCF content. This means that the piezo-damping effect really functions in BaTiO 3 / VGCF /LDPE composites and only in certain conditions can this effect have practical significance. Further examination of the damping behavior in a different relaxation region demonstrates that the piezo-damping effect is directly related to the relaxation behavior of the polymeric matrix. Also, the piezo-damping effect is highly temperature and frequency dependent. The dielectric measurements suggest that, before the formation of a certain critical conducting state, the energy dissipation approach of the piezo-damping effect may be mainly determined by the interfacial polarization effect in the composite. Thus, it may be inferred that the piezo-damping effect also contributes to the dramatic increase of the loss factor at the high temperature side of the α relaxation peak for the BaTiO 3 /LDPE composite and functions practically even if there is no presence of VGCF.

High loss factor piezoelectric damping composite with three-dimensional reduced graphene oxide as the conductive phase

“…3 According to the theory of piezoelectric shunt damping, adding an appropriate piezoelectric component and a conductive phase to damping materials can be advantageous for energy dissipation. [3][4][5][6] A number of composites with metals, 7 carbon black (CB), [8][9][10][11][12] carbon bers, [13][14][15][16] carbon nanotubes, [17][18][19][20][21] and graphene as the conductive phase have been prepared and investigated. However, to achieve the conductive percolation threshold, a lot of the conductive phase needs to be added, which may affect the performance of the matrix.…”

Theoretical analysis of the conversion from electrical into thermal energy in piezoelectric-conductive damping composites

“…Davis and Lesieutre [3] predicted the principle of shunt damping in the composites using a stress-strain model. It has been postulated that, through the synergy of the polymer viscoelasticity, interface friction and "piezo-damping" ef-fect, the damping properties of materials can be improved [4][5][6][7].…”

“…There have been many reports focusing on different polymer matrices, such as thermosetting epoxy resin [8], polyvinylidene fluoride [9], polystyrene [10], vinylidene fluoride-trifluoroethylene [11], chlorinated polyethylene [12] or chlorobutyl rubber [13], and different piezoelectric materials such as piezoelectric lead zirconate titanate [8,14], BaTiO3 [6,9] or lead magnesium niobate [14], as well as different conductive agents including carbon black or polyaniline [15]. The influence of frequency, conductivity, and capacity on the damping effect have been studied experimentally [4,12].…”

Experimental Investigation on the Electrical and Dynamic Mechanical Properties of PMN/Electrically Conductive Carbon Black/Butyl Composites

“…The damping mechanism of the three-phase composites is assumed to be the piezoelectric damping effect. The vibrating energy is first converted into alternating electrical energy by the piezoelectric effect of the piezoelectric particles and the electrical energy was further converted into Joule's heat through the networks of electrical conductive particles in the polymer matrix [13]. Although the piezoelectric damping effect has already been proposed by Sumita, etal [14], many related details about damping mechanism have not been well understood [15].…”