Maruzhenko O. Structure, electrical and thermal properties of nanocomposites filled with hybrid fillers

Object of research: regularities of the filler conducting phase formation and the influence of its structural organization on the mechanical, electro- and thermophysical properties of the filled nanocomposites. Aim of the work: establishment of patterns of morphological structure formation of polymer composites filled with individual and hybrid nano- and microfillers of different nature, study of the influence of structural organization on the electrophysical, thermal and mechanical properties of composites. Methods: optical and scanning electron microscopy, dielectric spectroscopy, two-electrode DC method for measuring electrical conductivity, transient plane source, differential scanning calorimetry, dynamic mechanical analysis. It was found that segregated systems with an ordered filler distribution lead to a significant decrease (in some cases by an order of magnitude) of the percolation threshold compared to a random filler distribution. It was shown that the concentration dependences of thermal conductivity of systems with different distribution of micro- and nanofillers can be adequately described using the Lichtenecker model. It was first established that the hybridization of carbon fillers by size or form factor is characterized by a synergistic effect that results in a significant reduction in the percolation threshold. It was established that due to the regular structure, segregated composites are more effective as shielding electromagnetic radiation materials due to the presence of internal multiple reflection of the electromagnetic wave. For the first time, it has been found that the hybridization of nanofillers by form factor leads to a significant increase in the absorption efficiency of electromagnetic radiation. For the first time, method for forming segregated structure of an elastic piezoresistive sensor material using a carrier polymer with conductive phase is formed. It has been shown that composite filled with hybrid filler provides high piezoresistive parameters and stable electrical response over a wide time and temperature range.