Evaluation of the role of carbon nanotubes on the electrical properties of poly(butylene-terephthalate) nanocomposites for industrial applications

In this article, innovative electrically conductive polymer nanocomposites based on poly(butylene terephthalate) (PBT) filled with carbon nanotubes (CNTs) at different concentrations, to be used in the automotive field, have been investigated. Field emission scanning electron microscopy (FESEM) analysis revealed how a good nanofiller dispersion was obtained, especially by using surface treated nanotubes and by processing these materials using a more restrictive screw configuration. Melt flow index measurements highlighted that the processability of these nanocomposites was reduced at elevated filler amounts, even if CNT surface treatment promoted a partial retention of the fluidity of the neat PBT. Thermal degradation stability was improved upon the addition of CNT, even at limited filler amounts. Differential scanning calorimetry measurements evidenced how the presence of CNT slightly increased both the crystallization temperature and the crystalline fraction of the materials. The additivation of CNTs promoted a stiffening effect at elevated CNT contents, associated to an evident embrittlement of the samples. Electrical resistivity measurements showed that the most interesting results (i.e. 2.6 101 Ocm) were obtained for nanocomposites with a total filler content of 3 wt%, processed using the more restrictive screw configuration. For these materials, it was possible to obtain a rapid surface heating through Joule effect at applied voltages of 12 V.The authors gratefully acknowledge Minlargilih Melak Amare for his collaboration in the experimental activities. The authors also acknowledge the Portuguese Foundation for Science and Technology (FCT) for project PEst-C/CTM/LA0025/2013 (LA 25—2015–2017). This research activity has been supported by Fondazione Cassa di Risparmio di Trento e Rovereto (CARITRO) within the project “Bando Caritro 2014 per progetti di ricerca scientifica finalizzati allo sviluppo di iniziative imprenditoriali.” The work was also supported by the National Interuniversitary Consortium of Materials Science and Technology (INSTM)