Extraordinary synergy in the thermal and electric properties of polymer matrix reinforced with hybrid fillers Synergie der thermischen und elektrischen Eigenschaften einer mit Hybrid-Füllstoffen verstärkten Polymermatrix Y. S. Perets 1 , L. L. Vovchenko 1 , L. Y. Matzui 1 , A. Zhuravkov 1 , A. V. Trukhanov 2 , O. A. Lazarenko 1 The effect of the incorporation of different combinations of electric conducting and non-conducting nanofillers into epoxy resin on the thermal and electric conductivity was studied. Graphite nanoplatelets (GNPs), multi-wall carbon nanotubes (MWCNTs) and carbon fibers (CFs) were used as the conductive fillers. The non- conductive ones were boron nitride (BN) or barium hexaferrite (BaFe 12 O 19 ). The con- tent of nanocarbon in composite materials (CMs) was varied from 1.0 to 6.0 vol%, the content of dielectric filler in composite materials was equal to 15.0 vol% boron nitride and 8.0 vol% BaFe 12 O 19 , respectively. The combination of electroconductive nano- carbon and non-conductive boron nitride particles showed an increase of the thermal conductivity (by a factor of 2 for hybrid composite materials boron nitride/graphite nanoplatelet/epoxy (4.5 vol% of nanocarbon) compared to the thermal conductivity of composite materials with single graphite nanoplatelets filler) and the electric con- ductivity, whereas the hybrid conductive fillers of various morphology (graphite nano- platelets/carbon nanotubes or graphite nanoplatelets/carbon fibers) did not show an improvement. On the other hand, the use of graphite nanoplatelets/carbon nano- tubes and graphite nanoplatelets/carbon fibers hybrid fillers lead to the anisotropy of the electric conductivity and a reversible change of the electric resistance after a compression up to 50 MPa due to improved elastic properties. Keywords: Hybrid fillers / polymers / composite materials / electric properties / thermal conductivity Schlüsselwörter: Hybridfüllstoff / Polymere / Kompositmaterialien / elektrische Eigenschaften / thermische Leitfähigkeit 1 Introduction Multi-wall carbon nanotubes and graphite nanoplate- lets have been proposed as perspective fillers in composites due to their good mechanical and physi- cal properties [1–5]. A number of performed studies of polymer-nanocarbon composite indicate that bet- ter dispersion and higher aspect ratio of nanocarbon fillers lead to a lower percolation threshold and good mechanical properties of composites [6–7]. How- Corresponding author: Y. S. Perets, Department of Physics, Taras Shevchenko National University of Kyiv, Volodymyrs’ka str. 64, Kyiv, 01601, Ukraine, E-Mail: peres2007@yandex.ua 1 Department of Physics, Taras Shevchenko National University of Kyiv, Volodymyrs’ka str. 64, Kyiv, 01601, Ukraine 2 Scientific-Practical Materials Research Centre of the National Academy of Sciences of Belarus, P. Brovki str. 19, Minsk, 220072, Belarus Mat.-wiss. u. Werkstofftech. 2016, 47, No. 2–3 DOI 10.1002/mawe.201600493 © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.wiley-vch.de/home/muw 278