Electrical and Mechanical Properties of Epoxy Composites Filled with Carbon and Co3O4 Nanoparticles

Authors T.A. Len, L.L. Vovchenko, L.Yu. Matzui, O.V. Turkov, A.V. Zhuravkov

Taras Shevchenko National University of Kyiv, Physical Faculty, 01601 Kyiv, Ukraine

Е-mail len148@gmail.com
Issue Volume 16, Year 2024, Number 1
Dates Received 20 December 2023; revised manuscript received 17 February 2024; published online 28 February 2024
Citation T.A. Len, L.L. Vovchenko, et al., J. Nano- Electron. Phys. 16 No 1, 01026 (2024)
DOI https://doi.org/10.21272/jnep.16(1).01026
PACS Number(s) 61.48.De
Keywords Cobalt oxide, Composite material (3) , Carbonyl iron, Electrical conductivity (10) , Mechanical properties (6) .

The study of samples of multicomponent epoxy composites (CM) was carried out, the structure, morphology of fillers and their distribution in the epoxy matrix were studied, the features of the process of modifying the conductive cluster and changing the interphase polarization due to the integration of nanocarbon (graphite nanoplates GNP, carbon nanotubes CNT) and inorganic (Fe, Co3О4) of superdisperse fillers, the influence of the composition, morphology and concentration of combined fillers on the electrodynamic characteristics of composites and the mechanisms of electrical transport in CM was determined. As shown by studies of the phase composition of magnetic powders by the X-ray diffraction method, cobalt oxide nanopowder consists of a pure Co3O4 phase, and carbonyl iron – of pure α-Fe. Experimental research of electrical resistance was carried out on direct current in the temperature range of 77-293 K. As studies have shown, the electrical conductivity of CM has a percolation character, that is, it increases sharply at a certain concentration (weight Сcr or volume φc) of the nanocarbon filler. The addition of inorganic fillers along with nanocarbon fillers leads to a change in the nature of the percolation curves. Changes in the electrical conductivity of three-phase CMs significantly depend on the size and morphology of nanocarbon particles.

The addition of nanocarbon filler GNP along with inorganic magnetic particles Со3О4 or Fe led to a decrease in the percolation threshold and a higher electrical conductivity of CM at a GNP content higher than 3 wt. %. When adding Co3O4 particles along with CNTs to the epoxy matrix, there are significant changes in the electrical conductivity at a CNT content of 1-5 wt. % was not observed.

The nature of the temperature dependence of the electrical resistance is different depending on the type and content of the two-component filler in the CM. For epoxy CMs with high electrical resistance, a significant decrease in electrical resistance is observed when heated from 77 to 293 K.

It was found, that the addition of 2-5 wt. % of graphite nanoparticles along with Co3O4 nanoparticles decreases the effective Young modulus and the compression strength of three-phase composites compared with Co3O4/epoxy. 5CNT/Co3O4/epoxy CM showed the minimal value of Young modulus (520 MPa) and enhanced flexible properties compared with composites with GNP/Co3O4 filler. The significant decrease in electric resistance (by 2 orders of magnitude) under uniaxial compression was found for 3GNP/Co3O4/epoxy CM with nanocarbon content close to the percolation threshold. The sufficiently lower reversible decrease of electrical resistance (not exceed 30 % relative to the initial value) was observed for 5 %GNP/Co3O4/epoxy composite.

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