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

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 epsilon' = 28 with a simultaneous decrease in dielectric loss (tan delta < 0.1) at f = 10(3) Hz for composites of PTFE/KFTO(H)@CB (30 vol.%).

Automated summary

In this study, polymer matrix composites of PTFE/KFTO(H) and PTFE/KFTO(H)@CB were produced and characterized using various methods. The addition of 2.5 wt.% carbon material in the polymer matrix composites was found to increase the permittivity and decrease the dielectric loss.