PERCOLATION EFFECTS IN COMPOSITE MATERIALS BASED ON NANOLAYER INORGANIC MATRICES

Techniques have been developed and experimental setups constructed to investigate the electrophysical characteristics of electrically conducting composite materials and binary heterogeneous dielectric-conductor systems at ambient temperature, including under pressure conditions. The electrophysical behavior of direct and alternating current composites in the systems of thermally expanded graphite and natural graphite has been studied in the range of 300–600 K. Percolation thresholds for electrical conductivity in these materials have been identified, and critical exponents in the scaling law of electrical conductivity were calculated. Based on an analysis of the frequency- and temperature-dependent electrical conductivity of the composites, it was demonstrated that the thermo-fluctuational mechanism of conductivity occurs in the thermally expanded graphite based composite up to the percolation limit. After reaching the percolation threshold, a transition to a hopping conduction mechanism with a variable hopping length is observed. Energy parameters in the thermal fluctuation model within the temperature range of 350 to 600 K and the Mott parameter within the hopping conductivity model with a variable jumping length within the temperature range from 373 to 573 K have been determined. It has been shown that there are regions of reduced electrical conductivity on the curve for the temperature dependence of electrical conductivity of vermiculite and composite materials based on vermiculite with increasing temperature. These regions are consistent with the findings of thermogravimetric analysis of vermiculite, which revealed two areas of weight loss in the temperature range between 320 and 750 K. The first section accounts for 8.7% and the second for 2.6%. Analysis of the emitted gases using an infrared spectrometer revealed only the presence of water vapor. For citation: Kalashnik A.V., Ionov S.G. Percolation effects in composite materials based on nanolayer inorganic matrices. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 9. P. 6-13. DOI: 10.6060/ivkkt.20256809. 3y.