The Effect of Processing Conditions on the Mechanical Properties of Polypropylene/Mesoporous Silica-Hydroxyapatite Hybrid Nanocomposites

This work focused on the influence of processing conditions on the mechanical properties of polypropylene (PP) and PP/mesoporous silica-hydroxyapatite (PP/MCM-41-HA) hybrid nanocomposites. The mechanical properties of PP were enhanced by adding MCM-41-HA nanoparticles. Neat PP and hybrid nanocomposites based on PP, containing maleic anhydride-grafted polypropylene (PP-g-MA) and MCM-41-HA, were prepared using the melt intercalation technique in an internal mixer. To optimize the processing conditions, both mixing temperature and rotor rotational speed were varied. Tensile and flexural tests were performed to evaluate some mechanical characteristics (stress-strain curves, tensile strength, tensile modulus, strain at rupture, flexural strength. and flexural modulus) of both the neat PP and PP/ MCM-41-HA hybrid nanocomposite materials. The results showed that two of the materials’ mechanical properties were most affected by two preparation parameters: shear rate and the distribution process of nanocomposites were found to be optimized using a mixing temperature of 180° C and a rotor rotational speed of 100 rpm to achieve the best mechanical properties. Under these conditions, the best mixing time was 3 min according to the torque diagram. Moreover, the PP/MCM-41-HA hybrid nanocomposite demonstrated a sensible enhancement of mechanical properties over neat PP.