PVA/SiO₂ nanocomposite films: evaluation of mechanical, thermal, optical and physico-schemical properties

Polyvinyl alcohol (PVA) films embedded with SiO 2 nanoparticles (33–59 nm) were studied for their mechanical, thermal, optical, and physicochemical properties. SiO 2 nanoparticle sizes were controlled using a modified sol–gel method. Characterization was done using field emission-scanning electron microscopy, X-ray diffraction, Fourier transform-infrared spectroscopy, UV–Vis spectroscopy, universal testing machine, and differential scanning calorimetry. Maximum tensile strength (45.7 MPa) was achieved for the particle size of SiO 2 as 33 nm. Mechanical strength increased from 18.3 MPa (pure PVA) to 47.3 MPa (6 wt.% SiO 2 ) and decreased at higher loadings. The melting point was enhanced from 210 °C (pure PVA) to 222.2 °C (6 wt.% SiO 2 ). Enthalpy of fusion increased from 3.9 J g −1 to 10.1 J g −1 , and % crystallinity from 2.3 % to 6.1 %. Density, chemical resistance, and water barrier properties were also enhanced. For achieving maximum tensile strength, optimal reagent concentrations for particle size and loading were determined using response surface methodology. This study highlights PVA/SiO 2 films as potential packaging materials with improved properties.