Experimental investigations on preparation of silica coated TiO₂ nanoparticles (S-TiO₂) and its mechanical characterizations as reinforcement in polylactic acid (PLA)/thermoplastic polyurethane (TPU) composites

Polymer composites exhibit unique properties that make them ideal for an extended range of industrial and engineering fields. However, the mechanical characteristics of polymer composites play a crucial role in assessing their applicability for specific load-bearing applications, and their failure mechanisms are largely influenced by these characteristics. This study examines the mechanical characteristics of Polylactic acid (PLA)/Thermoplastic polyurethane (TPU) polymer composites reinforced with silica-coated TiO2 nanoparticles(S-TiO2). The Sol-gel method was employed to coat nanoparticles with silica, to enhance their surface properties and functionalization, as well as to mitigate the photo-degradation of pure TiO2 nanoparticles. Morphology and micro structure of nano particles were evaluated by transmission electron microscopy (TEM), Energy-dispersive x-ray spectroscopy (EDS), Fourier-Transform Infrared Spectroscopy (FTIR) and x-ray diffraction (XRD). The PLA/TPU pellets were blended at 70/30 ratio and then reinforced with S-TiO2 at weight percentages ranging from 0.5% to 2.0%, in increments of 0.5%. SEM images have shown the existence and uniform distribution of TPU and S-TiO2 in PLA. The mechanical properties of fabricated polymer composites such as hardness, tensile strength, elongation at break, flexural strength, and impact strength were determined using various mechanical tests. Thermal behaviour of polymer composite was analysed by using Thermogravimetric Analysis (TGA). It was found that polymer composite containing 2% by weight of S-TiO2 exhibited an increase in hardness, tensile strength, and flexural strength by 10.3%, 23.2%, and 20%, respectively.