High-Density Polyethylene Composites Filled with Nanosilica Containing Immobilized Nanosilver or Nanocopper: Thermal, Mechanical, and Bactericidal Properties and Morphology and Interphase Characterization

Silica containing immobilized nanosilver (Ag-SiO2) or nanocopper (Cu-SiO2) was used as a filler for high-density polyethylene (HDPE). The HDPE/Ag-SiO2 and HDPE/Cu-SiO2 composites were prepared by melt blending and injection molding. The microstructure of the composites was examined using transmission electron microscopy (TEM). The crystallization behavior and thermal properties were studied using differential scanning calorimetry (DSC) and thermogravimetry (TGA). The mechanical properties were characterized by tensile, flexural, and impact tests as well as dynamic mechanical thermal analysis (DMTA). The ability of silica to give antimicrobial activity to HDPE was also investigated and discussed. The TEM images indicate that Ag-SiO2 show lower degree of agglomeration than Cu-SiO2 nanoparticles. The crystallization temperature increased, whereas crystallinity decreased in the composites. The thermal stability of the composites was significantly better compared to HDPE. Improved stiffness indicating very good interfacial adhesion was observed. Excellent activity against different kinds of bacteria was found.