Abstract
By the extrusion and injection technique, polymer-based composite samples (polypropylene and thermoplastic polyurethane) were obtained with BaTiO3 filler in concentrations between 0 and 35 %. Following the preliminary characterizations performed by coupled thermal analysis techniques, it was found that the composite samples obtained have thermal stability up to a temperature of about 250 oC and can be processed by extrusion at temperatures between 180 and 240oC. Above this temperature, a series of degradation processes take place by successive thermooxidation with the formation of volatile products.The electrical characterization of the composite samples was performed by the dielectric spectroscopy technique, which showed that the Ätgä dielectric losses increase as the BaTiO3 content of the composite increases. The maximum increase being recorded at 50 Hz (the slope Ätgä /% BaTiO3 about 0.003 /% BaTiO3). It was also found, that the electrical conductivity (ó) of the composite increases with the increase of content in BaTiO3 so that ó at 100 kHz for the composite with 35 % BaTiO3 is about 50 times higher than for the reference sample M 0 (without filler).
Keywords: composite; thermoplastic polyurethane; polypropylene; BaTiO3; dielectric loss; conductivity