The effect of accelerated UV-ageing on the dielectric properties of PVC, PTFE and HDPE

In this work the dielectric response of three commonly used polymeric insulating materials, namely polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE) and high-density polyethylene (HDPE), was measured after applying combined action of UV-radiation and condensation (humidity and heat) in an Accelerated Weathering Tester apparatus. Test samples were planar with a 2 mm thickness. For both aged and non-aged samples, the dielectric properties (relative dielectric constant κ' and dissipation factor tanδ) were recorded in a frequency range 20 Hz-1 GHz. The induced changes on complex permittivity after applying UV/condensation cycles were described. The accelerated ageing led to surface color differentiations for PVC and HDPE. Finally, Fourier Transform Infrared (FTIR) spectroscopy measurements on the sample surfaces investigated the chemical stability of the tested materials.