Tuning electrical and thermal conductivity of polyurethane-based insulating systems by hallosite nanotube doping

The presented work investigates the effect of Halloysite Nanotubes (HNTs) doping on the electrical and thermal transport behavior of polyurethane (PUR) systems designed for advanced electro- insulating applications. Three representative PUR compounds: VUKOL N22, VUKOL N22 Magna Blue, and VUKOL N70 were selected as model matrices due to their established use in encapsulation and potting materials for power electronics. Each system was modified with 2 wt.% and 5 wt.% of HNT nanofillers in order to analyze the extent to which tubular aluminosilicate nanoparticles alter charge conduction and heat dissipation within the polymer bulk. Electrical measurements revealed that the inclusion of HNTs strongly affects the conduction process, primarily through enhanced interfacial polarization, carrier trapping, and modification of percolation pathways between polymer chains. Thermal conductivity analysis showed a moderate but systematic increase, indicating more efficient phonon transport and partial formation of thermally conductive microchannels mediated by well-dispersed nanotubes. The results confirm that controlled HNTs incorporation enables precise tuning of both electrical and thermal properties of PUR systems, offering new perspectives for the design of multifunctional insulation materials with improved dielectric stability and thermal management, particularly suitable for emerging high-voltage, high- temperature, and energy-dense power devices.