Vinyltriethoxysilane (VTES) was covalently bonded onto graphene oxide. Several methods, including X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction, were used to demonstrate the presence of VTES on the surface of graphene oxide and the creation of this covalent link. Following that, different quantities of the resultant vinyltriethoxysilane functionalized graphene oxide (VTESFGO) were mixed with polyvinyl alcohol (PVA) to form VTESFGO/PVA nanocomposite films (NCFs) with a 3-dimensional network structure. The creation of these NCFs and the presence of a three-dimensional network were confirmed by Fourier transform infrared spectroscopy. The three-dimensional network structure provided these NCFs extraordinary characteristics. The mechanical and thermal stability, oxygen transfer rate (OTR), and water resistance pressure (WRP) of the NCFs were investigated. The nanocomposite film (NCF) with the highest weight percentage of VTESFGO (3.0 wt.%) was 47.5% more thermally stable than pure PVA, with an oxygen transmission rate of 0.3 cm3/m2 per day and a water resistance pressure of 780 mm/cm2. However, as the weight percentage of VTESFGO increased, the mechanical strength of the NCFs decreased as a result of silanol self-condensation, resulting in particulate formation, as confirmed by scanning electron microscopy.