Enhanced electrical and thermal performances of nanostructured epoxy/POSS composites

Epoxy resins modified with Glycidyl-POSS (Polyhedral Oligomeric Silsesquioxanes) in contents of up to 20 wt% were fabricated and studied in terms of dielectric spectroscopy, differential scanning calorimetry, AC breakdown tests, thermal conductivity measurements and corona resistance. Microstructure analysis have revealed a molecular dispersion of Glycidyl-POSS up to contents of 10 wt%, whereas in the 20 wt% POSS composites crystalline zones due to POSS could be observed by both scanning electron microscopy and transmission electron microscopy. All POSS composites have seen a significant improvement in AC breakdown strength, as well as an enhanced resistance to corona discharges, which in the latter case was getting more pronounced with higher POSS loadings. On the contrary, low POSS contents proofed most effective in improving the thermal conductivity, which should be attributed to the effect of POSS on the nanostructure of the polymeric network.