The effect of dispersant on toughening mechanism and structure behaviors of Polypropylene Nanocomposites reinforced with nano α-alumina particles

Abstract

This article presents a comparative study on the effects of using nano α-alumina (Al2O3) on toughening mechanisms and structural behaviors of polypropylene (PP) nanocomposites. The role of using dispersant in nanocomposite preparation was also investigated. For nanocomposite preparation, mixing of the elements was performed using a Haake Poly Drive blending machine at 175°C and the rotor speed of 50 rpm. The notched Izod impact energy obtained for PP was about 27 J/m and by the addition of nano α-Al2O3 (4 wt%) to PP, the notched Izod impact energy increases up to ∼43 J/m. However, higher concentration of nano α-Al2O3 in the nanocomposite resulted in the reduction of Izod impact property due to nano α-Al2O3 agglomeration. Fourier transform infrared spectroscopy (FTIR) spectra of pure PP and PP/nano α-Al2O3 composites demonstrated Al–O bond at 568 cm−1 for nanocomposite spectrum that indicates the creation of nano α-Al2O3 particles. The x-ray diffraction patterns and FTIR spectra of PP/nano α-Al2O3 composites showed that the intensity of the peaks when dispersant was used slightly increased and the arrangement of the peaks are normalized. This observation is attributed to homogeneous dispersion of nano α-Al2O3 filler in the matrix when dispersant was used. Scanning electron micrograph of impact fractured surface showed that the fracture surface of PP/nano α-Al2O3 composite becomes rougher with increasing the content of filler.