Thermal behavior and mechanical properties of nanocomposites of polycarbonate reinforced with multiwalled carbon nanotubes

Nanocomposites of polycarbonate (PC) reinforced with different contents (0–10 wt%) of multi‐walled carbon nanotubes (MWCNTs), PC/MWCNT, were prepared in a two‐step dispersion process: extrusion followed by injection molding. The effects of the MWCNT content and injection conditions on thermal, mechanical, and dynamic mechanical properties of the prepared nanocomposites were investigated and compared. Thermogravimetric analysis showed that a small MWCNT content (i.e., 1 wt%) was more propitious for improving thermal stability of the nanocomposites. Analysis of the mechanical properties demonstrated that the tensile properties of the nanocomposites with low MWCNT content could be comparable to that of PC; but as the content was increased to 10 wt%, the tensile strength and bending strength decreased by 35% and 47%, respectively, from the values for PC. The impact strength and microhardness was improved; however, with the increase in MWCNT content. Results of dynamic mechanical analysis showed that the storage modulus of PC was increased by the incorporation of MWCNTs, particularly at high temperatures. Scanning electron microscopy was also carried out to investigate the microstructures of the nanocomposites. It is concluded that the incorporation of MWCNTs by injection molding was more effective in enhancing the thermal, mechanical, and dynamic mechanical properties of PC. POLYM. COMPOS., 38:E303–E313, 2017. © 2015 Society of Plastics Engineers