Funct. Mater. 2020; 27 (1): 54-66.
Comparative analysis of thermal conductivity of polymer composites with random and segregated distribution of single and hybrid nanocarbon filler
1Department of Physics, Taras Shevchenko National University of Kyiv, 64/13 Volodymyrska Str., 01601 Kyiv, Ukraine
2Institute of Macromolecular Chemistry, National Academy of Sciences of Ukraine, 48 Kharkivske Chaussee, 02160 Kyiv, Ukraine
The article is devoted to the study of concentration and temperature dependences of heat conductivity for composites with random distribution of mono or hybrid fillers in low viscosity resin Larit285 and segregated structures on the basis of ultra-high molecular weight polyethylene. A mono filler is graphite nanoplatelets or carbon nanotubes, a hybrid filler is a combination of graphite nanoplates and carbon nanotubes in different ratios (1:1, 3:1, and 0.2:x, vol.%). Concentration dependences of thermal conductivity have shown that graphite nanoplates are a more effective filler for increasing thermal conductivity. In segregated systems with carbon nanotubes, the thermal conductivity even decreases in comparison with the polymer matrix due to contact and interphase thermal resistance. Carbon nanotubes have a large specific surface, which contributes to the formation of a large number of interphase boundaries. For hybrid composites with a content of a hybrid filler more than 3-5 vol.%, a synergistic effect is observed, and the maximum increase in thermal conductivity is 465% for the xCNT-xGNP/L285 composite. The type of the temperature dependences of thermal conductivity, both for mono and for hybrid composites, is mainly due to the competition of two processes: an increase in the number of phonons when heated and growth of phonon scattering.
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