Estudo e caracterização de acessórios poliméricos usados em redes compactas

Abstract

Polymerics mooring rings and lozenge spacers are used as accessories in compact power distribution networks. In this study, samples of elastomeric rings were subjected to accelerated aging by environmental and electric stresses. Sample of the mooring ring new,samples of this ring subjected to accelerated aging, sample of aged ring in service for 10 years, sample of lozenge spacer new and samples of spacers naturally aged in service during 12 and 21 years were characterized by Fourier transform infrared spectroscopy (FTIR),differential scanning calorimetry (DSC), thermogravimetry (TGA), scanning electron microscopy (SEM) and hydrophobicity test. Samples of spacers were also subjected to rheological tests to determine the average molar mass as well as two samples of morring rings were analysed to determination of degree of crosslinking. The results for the mooring ring showed change in the composition of the surface of the aged sample in service, as well as on the surface of the samples submitted to accelerated aging, compared to the sample new. Theanalysis by FTIR and MEV indicated that the simulation of electrical stress was more aggressive to the surface of the rings when to compared the simulation of environmental stress. Spacers aged in service also showed abnormalities in the composition of the surface of these samples. The presence of oxygen on the surface of the spacers, with formation of carbonyl groups characteristic of ester, was observed by FTIR and energy dispersive x-ray spectrometer (EDS). Samples of inner of accessories were analysed by FTIR spectra showing no evidence of degradation and indicating that the surface of these materials is more likely to changes.