The influence of carbon nanotubes on the electric conductivity of thermosetting plastics and elastomers

Abstract

: In the technology of electricity-conducting polymer composites, the up-to-date topic is the application of modifiers with nanoscale geometric parameters. Such materials are both single-wall and multi-wall carbon nanotubes. The use of multi-wall carbon nanotubes as additives to polymers allows achieving good results associated with the electrical conductivity manifestation at the low percentage ratios of the introduced carbon nanotubes. The study considered two different types of polymers: epoxy resin and silicone. For modification, the authors used the multilayer carbon nanotubes (MCNT). For silicone, the authors studied the electrical conductivity at the mechanical deformations, in particular, at torsion with different twist angles. The study considered the influence of MCNT with different bulk density on the electrical conductivity of composites. At the 100 Hz measurement frequencies for identical additive concentrations with 1, 2, 4, and 8 wt.% in composites with the “Taunit - M” MCNT, the conductivity is about by 2 orders of magnitude larger than in co m-posites with “Taunit” MCNT. A polymer modified by an MCNT with a specific surface a rea of 202.3 m2/g has a lower specific resistivity (3.8 × 105 Ohm×cm). The MCNT modifier with a specific surface area of 202.3 m2/g, which is smaller in comparison with other types of MCNT, and a bulk density of 42.6 kg/m3 allows obtaining the lowest electrical resistivity. An MCNT with a high specific surface area of 541.5 m2/g causes the formation of electrical conductivity by 2 orders of magnitude lower than an MCNT with a specific surface area of 202.3 m2/g. The study identified that at the mass content of MCNT 1.5 and 2 mass.%, the composites are characterized by an increase in electrical resistivity at torsion angles from 0 to 900°.