Polyethylene/polyhedral oligomeric silsesquioxanes composites: Electrical insulation for high voltage power cables

Xylene solution blending was tested as a method for producing low-density polyethylene (LDPE)-based nanodielectrics containing 1 wt% and 5 wt% polyhedral oligomeric silsesquioxanes (POS) of different types - octamethyl POS, octaisobutyl POS, and isooctyl POS. The chemical composition, the morphology, the thermal properties and the dielectric properties of LDPE and its composites were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, thermal conductivity measurements, broadband dielectric spectroscopy, progressive-stress breakdown tests, and surface partial discharge tests. The results showed that although xylene solution blending was an effective method for producing LDPE/POS dielectric composites, it appeared ineffective in dispersing POS at the nanoscale. Furthermore, some of the composites presented an improved thermal conductivity, a maintained breakdown strength and an enhanced resistance to corona discharges.