Preparation and characterization of polypropylene nanocomposites containing polystyrene-grafted alumina nanoparticles

After surface modification of gamma-Al2O3 nanoparticles with a silane coupling agent, styrene was graft-copolymerized onto gamma-Al2O3 nanoparticles using a simultaneous gamma-ray irradiation technique. The influence of the irradiation dose and the grafting kinetics were investigated in detail. Polypropylene nanocomposites were fabricated by blending polypropylene, polystyrene-grafted gamma-Al2O3 (gamma-Al2O3-g-PS), and a small amount of 1,4-butandiol dimethacrylate (1,4-BDDA) as a crosslinker, followed by e-beam irradiation. The polystyrene-grafted gamma-Al2O3 and polypropylene nanocomposites were characterized by TGA, FT-IR spectroscopy, SEM, and UTM analyses. The polystyrene graft yield onto gamma-Al2O3 increased with the absorbed dose. The graft yield was higher at 50 vol% of the styrene solution than at 70 vol%. The nanocomposite fabricated with 5 phr of gamma-Al2O3-g-PS and 3 phr of 1,4-BDDA showed the highest tensile strength. The homogeneous dispersion of gamma-Al2O3-g-PS into the polypropylene matrix and the crosslinking through e-beam irradiation improved the mechanical properties of the nanocomposites.