Electrical and Thermal Conductivity of Ternary Composites Graphite Nanoplatelets/TiO2/Epoxy

Authors L.L. Vovchenko , T.A. Len , L.Yu. Matzui , O.V. Turkov , Yu.S. Perets
Affiliations

Taras Shevchenko National University of Kyiv, Physical Faculty, 64/13, Volodymyrska St., 01601 Kyiv, Ukraine

Е-mail len148@gmail.com
Issue Volume 11, Year 2019, Number 3
Dates Received 06 March 2019; revised manuscript received 12 June 2019; published online 25 June 2019
Citation L.L. Vovchenko, T.A. Len, L.Yu. Matzui, et al., J. Nano- Electron. Phys. 11 No 3, 03007 (2019)
DOI https://doi.org/10.21272/jnep.11(3).03007
PACS Number(s) 72.80.Tm, 72.90 + y, 65.80.Ck
Keywords Titanium oxide, Graphite nanoplatelets, Composite (42) , Electrical conductivity (10) , Thermal conductivity (2) .
Annotation

The investigation of the electrical and thermal properties of composite materials (CMs) based on epoxy resin L285 and hybrid filler graphite nanoplatelets/titanium oxide particles (GNP/TiO2) has been performed. The experimental study involved measuring direct current (DC) resistivity in the temperature range 77-293 K and thermal conductivity (within 150-425 K range) of such ternary composite with 0-5 wt. % content of GNP particles and 35 wt. % of TiO2 ultra-disperse (~130 nm) particles. The decrease of the percolation threshold and enhanced electrical conductivity for the ternary GNP/TiO2/epoxy CMs compared with binary GNP/epoxy CMs were observed. It was found that the increase of highly conductive GNP content in the composite leads to the increase of electrical conductivity and change in the temperature coefficient of resistance (TCR) from negative to slightly positive in the temperature range 100-293 K. The negative TCR was related to hopping mechanism of conductivity, and the activation energy for low-conductive 2 wt. % GNP/TiO2/epoxy composite was estimated. The positive TCR for 5 wt. % GNP/TiO2/epoxy composite may be explained by the changes in tunnel electronic transport under thermal expansion of epoxy matrix. The investigation of thermal conductivity of GNP/TiO2/epoxy CMs has shown that addition of TiO2 particles into GNP/epoxy composites doesn’t influence the value of thermal conductivity. The changes of the thermal conductivity with increase of GNP content in ternary CMs were considered within a modified Nielsen model and the effective thermal conductivity of each type of filler phase was determined. The role of the thermal interface resistance and interparticle thermal contact resistance in the determination of composite thermal conductivity was also discussed.

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