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

Abstract

In this work, polymer matrix composites with the compositions PTFE/KFTO(H) and PTFE/KFTO(H)@CB and with filler volume fractions of 2.5, 5.0, 7.5, 15, and 30% (without and with carbon modification at a content of 2.5 wt.% regarding ceramic material) were produced by calendering and hot pressing and studied using FTIR, SEM, and impedance spectroscopy methods. Ceramic filler (KFTO(H)) was synthesized using the sol–gel Pechini method. Its structure was investigated and confirmed by the XRD method with following Rietveld refinement. The carbon black (CB) modification of KFTO(H) was carried out through the calcination of a mixture of ceramic and carbon materials in an argon atmosphere. Afterwards, composites producing all the components’ structures weren’t destroyed according to the FTIR results. The effect of carbon additive at a content of 2.5 wt.% relating to ceramic filler in the system of polymer matrix composites was shown, with permittivity increasing up to ε’ = 28 with a simultaneous decrease in dielectric loss (tanδ < 0.1) at f = 103 Hz for composites of PTFE/KFTO(H)@CB (30 vol.%).

Molten salt-shielded synthesis of Ti3AlC2 as a precursor for large-scale preparation of Ti3C2Tx MXene binder-free film electrode supercapacitors

“…To obtain Ti 3 AlC 2 MAX phase powder, the molten salt shielded synthesis in open air technique was used, similar to the previously described methods. 34,35 TiC (550 mesh, 99.6%, Sichuan Porous Metal Technology Co., Ltd), Ti (400 mesh, 99.9% Sichuan Porous Metal Technology Co., Ltd), and Al (120 mesh, Chengdu WOCO Carbide Industry Co., Ltd) powders were used as reagents. First, the powders were mixed in a stoichiometric molar ratio of 2 : 1 : 1.4 (TiC : Ti : Al) in a PLANETARY MONO MILL Fritsch PULVERISETTE 6 at 300 rpm for 30 min using ZrO 2 balls with 4 mm diameter.…”

Significantly Enhanced Balance of Dielectric Properties of Polyvinylidene Difluoride Three-Phase Composites by Silver Deposited on K2Ni0.93Ti7.07O16 Hollandite Nanoparticles

“…Therefore, it is extremely important to ensure good interfacial adhesion between the ceramic particles and the polymer matrix [ 35 ]. Considering the potential for low filler loading, conductive fillers such as carbon nanomaterials [ 36 , 37 ], metal nanoparticles [ 38 , 39 , 40 , 41 ], and MXenes [ 42 , 43 , 44 ] are of greater interest. In this case, a significant increase in the dielectric constant occurs near the percolation threshold; however, the conducting particles inevitably form conducting paths, which leads to an increase in the conductivity of the composites and high dielectric losses.…”

“…In addition, recent publications report that hollandite-like solid solution ceramics can exhibit high dielectric constants (ε ′ = 10 3 -10 4 ) [61,62], which also makes them attractive materials as ceramic fillers for high dielectric polymer composites. Previously, hollandite-like solid solutions K x Ti 8-y Me y O 16 (Me = Cu, Ni, Fe) were studied as fillers for PMMA, Epoxy, PVDF, and PTFE matrices [63][64][65][66]; however, these composites demonstrated an increase in dielectric constant and strong increase in dielectric losses. An effective way to inhibit dielectric losses in the case of PTFE and PVDF polymer matrices was to use a three-phase strategy in the preparation of composites.…”

Composite High-k Films Based on Polyethylene Filled with Electric Arc Furnace Dust and MWCNT with Permittivity Synergetic Effect

“…Another approach is the deposition of a carbon coating using carbon black as a result of annealing in an argon atmosphere. In all cases, the addition of a conductive material at an optimal concentration of ceramic filler provides an increase in the value of ε by a factor of 3-10 relative to a pure polymer, depending on its type and composition of the composite [26][27][28].…”