Dielectric Spectra of Polyurethane Casting Resins for Electrical Engineering Applications

Polyurethane-based casting compounds are crucial in electrical engineering. Despite their long history of use, research and optimization of their applications remain important. This study compares two different polyurethane-based materials suitable for high-voltage electrical applications, focusing on their dielectric properties. The experiment involved measuring volume resistivity, loss factor, and permittivity, as well as conducting a broadband dielectric spectroscopy analysis. The chemical composition of the tested materials was further characterized using Fourier transform infrared spectroscopy and hardness measurements were also conducted. The first tested material serves as the reference in this experiment, being commonly used. The second material was included in the experiment as a potential replacement for the first material because it exhibited significantly higher bulk resistivity and optimal polarization behaviour during the first analyses.