Effect of Addition of Carbon Nanotubes on Electrical Conductance and Heat Dissipation of Elastomers at Flow of Direct Current

Abstract

The heat effects at flow of direct current in nanomodified elastomers of two types (polyurethane and silicone compounds) were investigated. The multiwalled carbon nanotubes (MWCNT) synthesized over the (Co–Mo)/(Al2O3–MgO) and (Fe–Co)/2.1Al2O3 catalysts were used for nanomodification. The particle size analysis of MWCNT was carried out because the MWCNTs with various morphological parameters were synthesized over this type of catalysts. The composite manufactured on the basis of a silicone compound modified by 7 wt % of MWCNTs synthesized over the (Co–Mo)/(Al2O3–MgO) catalyst has the highest electrical conductivity (1.66 × 10–1 S cm–1), and the composite manufactured from the polyurethane compound modified by 1 wt % of MWCNT synthesized over the (Fe–Co)/2.1Al2O3 catalyst has the lowest electrical conductivity (6 × 10–10 S cm–1). Variations in heat dissipations for various types of elastomers modified by MWCNT were detected by using the noncontact method of measuring of temperature field on the surface of samples. The manner of stabilized heat dissipation which is natural for the materials with a positive temperature coefficient of resistance was found. The highest intensity of heat dissipations combined with uniform distribution of the temperature field was observed for the samples manufactured on the basis of a silicone compound containing 7 wt % of the MWCNTs synthesized over the (Fe–Co)/2.1Al2O3 catalyst. The maximum heating temperature for the sample operating under the voltage of 6 V of direct current was 102°C. Nonuniformity of heat dissipations is specific to almost all samples manufactured on the basis of the polyurethane compound. In this case, the samples based on the silicone compound demonstrate uniform heating at any level of filling by the MWCNTs. As a part of the study, a honey-combed sample was obtained, which, under the voltage of 6 V of direct current, was heated to 100°C and had a uniform distribution of the temperature field.