Investigation of thermal, mechanical and gas barrier properties of polypropylene-modified clay nanocomposites by micro-compounding process

Polypropylene (PP) nanocomposites were prepared by the melt extrusion of PP with modified clay in the presence of maleated polypropylene (PPgMA). Before melt extrusion, clay was modified by a sol-gel method with two different modifiers (amionpropyltriethyoxysilane and dimethyloctadecyl [3-(trimethoxysilyl)propyl] ammonium chloride) and further treated with tetraethyl orthosilicate. The modification of the clay was confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and surface area analysis. The dispersion morphology of these nanocomposites was confirmed by XRD and TEM analyses. The storage modulus of PP nanocomposites was increased by 15.5%, and tensile strength improved by 45.9% compared to pure PP. Gas barrier properties were investigated, and the results showed that the O-2 permeability at 3 atm improved by a factor of 14.1 over pure PP. The surface contact angle was reduced from 97.90 degrees to 67.72 degrees, indicating increased hydrophilicity. These results suggest the potential of PP composites. (C) 2018 Published by Elsevier B.V. on behalf of Taiwan Institute of Chemical Engineers.