Polytetrafluorethylene‐based high‐k composites with low dielectric loss filled with priderite (K_1.46Ti_7.2Fe_0.8O₁₆)

Abstract

Composite materials with a high permittivity (high‐k) and low dielectric loss represent an important research direction for the rapid development of modern electronic. This article is about high‐k composite with low dielectric loss (dielectric constant is approximately 11, and dielectric loss is only 0.02 at 1 MHz and about 50 wt % of filler) based on a polytetrafluorethylene (PTFE) compounded with priderite (K1.46Ti7.2Fe0.8O16). The dielectric permittivity about ε' ≈ 103 and the dielectric loss of tgδ ≈ 2 have been found for filler content about 50 wt % (30 vol %) and, respectively, ε' ≈ 11 and tgδ ≈ 0.02 for 1 MHz. To produce filler, amorphous potassium polytitanate was synthesized by molten salt method, modified in aqueous solution of iron sulfate, crystallized at 700 °C and further treated in the aqueous dispersion of PTFE. The obtained product was pressured, dried and investigated by X‐ray diffraction and scanning electron microscopy. Dielectric properties of the composite with different ceramic filler content (1–90 wt %) were studied using impedance spectroscopy in the frequency range of 10−2 to 106 Hz. The influence of frequency on electric conductivity, permittivity, and dielectric losses was analyzed taking into account the experimental data on porosity, apparent density obtained for the composites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48762.

Carbon Modification of K1.6Fe1.6Ti6.4O16 Nanoparticles to Optimize the Dielectric Properties of PTFE-Based Composites

“…For all samples in the low-frequency region, a sharp increase in permittivity is observed, associated with the formation of interphase boundaries and the accumulation of charge carriers on these boundaries, which form dipoles under the influence of an external electric field. It should be noted that the use of small KFTO(H) particles contributes to a more effective increase in permittivity with decreasing porosity compared to larger particles of similar composition studied in [ 28 ]. This also indicates an increase in the number of interfacial boundaries and an important role for interfacial polarization in the mechanism of permittivity increasing.…”

“…Potassium titanates with a hollandite structure doped with various transition metals can be an analogue of modern high-K materials as effective ceramic fillers for polymer matrices [ 24 , 25 , 26 , 27 ]. In several studies [ 28 , 29 , 30 ], the possibility of increasing the permittivity with the introduction of hollandite-like potassium titanates doped with iron, copper, and nickel ions into polymer matrices based on PTFE, PMMA, and epoxy has been shown. However, in these works, the titanate powders were produced by solid-state reaction and had particle sizes of a few micrometres, which can significantly reduce the effectiveness of the increase in permittivity.…”

Surface-modified Zn0.5Ti0.5NbO4 particles filled polytetrafluoroethylene composite with extremely low dielectric loss and stable temperature dependence

“…Simultaneously, the thermal conductivity, CTE, moisture absorption, and flexure strength are all appropriate for the substrate materials. Therefore, the Zn 0.5 Ti 0.5 NbO 4 ceramic particles are the perfect filler for PTFE-based substrate materials [28][29][30][31][32][33][34][35].…”

High-k Three-Phase Epoxy/K1.6(Ni0.8Ti7.2)O16/CNT Composites with Synergetic Effect

“…The efficiency of hollandite-like structures in the creation of polymer-matrix composites with an optimal combination of dielectric properties was previously shown using the example of systems [ 32 , 33 , 34 ]. Carbon nanotubes (CNTs) are known for their excellent conductivity and, at a relatively low content, do not deteriorate the mechanical properties of composites, which together opens up wide opportunities for the development of new composite polymer matrix materials.…”