Produção e caracterização de materiais poliméricos para recobrimento de cabos condutores

Abstract

The covered cables (protected cables and/or insulated cables), among the various devices of the electric sector produced with polymeric materials stand out in the compact power distribution networks. Obtaining polymeric coating for conductor cable to withstand higher ultraviolet radiation and electrical tracking is of fundamental importance to use in compact networks. In this work different samples of crosslinked polyethylene (XLPE) with and without carbon black additive (NF), and coated and uncoated with titanium dioxide nanoparticles (TiO2) were produced to be applied as coating conductor cable. The samples were submitted to accelerated aging by environmental stress (ultraviolet radiation, temperature and humidity) in a climatic chamber, during 1,000 and 2,000 hours. Before and after the accelerated aging, the samples were characterized by the following techniques: hydrophobicity, Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), thermogravimetry (TG) and differential scanning calorimetry (DSC). Both the presence of NF and and/or TiO2 coating does not affect significantly the hydrophobicity of XLPE samples as well as the accelerated aging for 1,000 and 2,000 hours in artificial weathering chamber. It could be observed from SEM images that samples containing NF and coated with TiO2 bore further surface degradation process compared with other samples. In general, the results obtained by FTIR, TG and DSC indicated that the presence of NF at different concentration showed a better resistance of the XLPE to accelerated aging by environmental stress. The coating of the sample with TiO2 do not interfere in the hydrophobicity and oxidative stability of samples containing NF, but it can influence the surface degradation of the samples, particularly when they were exposed to accelerated aging in climatic chamber by environmental stress. The use of the two types of NF additive and the TiO2 coating was not sufficient to prevent the effect of ultraviolet radiation on the degradation of the surfaces of these samples, while observing differences in the degradation suffered by the samples due to the addition of the NF and the coating with TiO²