In this study, polypropylene nanocomposites were fabricated using multi-wall carbon nanotubes (MWCNTs) and some mechanical and electrical properties of the nanocomposites were studied. The aim of this study was to investigate the effect of three important processing parameters of banbury internal mixer including rotor speed, mixing time and temperature and also investigate the optimum level of MWCNT’s loadings on some mechanical and electrical properties of the nanocomposites. Design of experiment (DOE) was carried out by statistical Taguchi method and the optimum values of these parameters were determined using minitab15 software. Nine compounds were prepared according to L9 orthogonal array of the Taguchi method in a Haake Rheomix internal mixer. Two sheets for each compound were prepared using compression molding method to prepare standard test specimens for characterization. Tensile tests and electrical resistivity of compounds were measured. Results were statistically analyzed with 95% confidence using Qualitek 4 software. The optimum values of rotor speed, mixing temperature and time were 80 rpm, 180 ?C and 25 min, respectively. Increasing the amount of MWNTs from 0 to 0.75 wt%, increases the electrical conductivity of the nanocomposites by 80%, however it decreases the tensile modulus, elongation at break and ultimate tensile strength of the samples. The X-ray diffraction pattern of PP/MWCNTs shows that the MWNTs do not affect the crystalline polymorph of PP and it acts as ? nucleating agent in PP crystals. The tensile modulus of the samples were compared with some well-known models including mixture rule, Hashin-Shtrikman and Halpin-Tsai models. The obtained experimental data were higher than the predicted values by those three models.
