Synthesis of Carbon Nanotubes Using Microwave Radiation to Modify Elastomer with Improved Electrical and Thermal Conductivity

Abstract

The paper presents a method of microwave influence on ferrocene C₁₀H₁₀Fe and graphite to obtain multilayer carbon nanotubes (MWCNTs)—designed to improve the electrical and thermophysical properties of Organosilicon elastomer (Silagerm 8020). Diagnostics and characterization of the synthesized MWCNTs were carried out by energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. According to SEM data, it follows that the morphology of the synthesized MWCNTs has the form of filamentous formations intertwined in bundles with a diameter of individual MWCNTs from 40 to 60 nm and a length up to several microns. At the same time, the surface of most of the MWCNTs is covered with a continuous layer of iron (Fe). The EDX method also confirmed the Fe and oxygen content on the surface of the MWCNTs. The XRD method identified the presence of Fe in combination with carbon in the form of Fe₃C iron carbide and pure Fe iron at 44.7°. The compound Fe₃C is also referred to the active phase of Fe allowing the synthesis of MWCNTs. By increasing the concentration of MWCNTs in the elastomer, an increase in thermal conductivity with percolation transition was achieved at a concentration of 8% MWCNTs. The maximum thermal conductivity of the nanomodified elastomer was 0.48 W/(m °C), which corresponded to the mass concentration of MWCNTs equal to 8 wt %. At the same time, the electrical conductivity of the composite, when the MWCNT concentration was changed from 1 to 8%, increased in the range from 4 × 10^–5 to 2.4 S cm^–1 and is also due to the percolation of MWCNTs in the elastomer matrix.