Polyvinyl butyral (PVB) exhibits exceptional characteristics, flexibility, and recyclability. Composite materials can be created with different inorganic species. Both hydrophilic and hydrophobic vinyl butyral groups were found in PVB which act as binders for organic moieties and promoters of polymer sticky. A coupling agent was used to prevent film defects and improve compatibility between the inorganic and organic phases. In this study, the nanocomposites prepared from PVB and silicon dioxide SiO2 with different ratios 1%, 3%, 5%, and 7% using solution casting method with and without coupling agent 3-glycidyloxypropyltrimethoxysilane were used as sustainable binding agent for nonwoven polyester. The prepared films were characterized by FTIR and XRD. The morphology was studied using SEM. Thermal stability TGA was studied, and it was found that the coupling agent made the silica well dispersed into the PVB, but it did not affect the increase in the SiO2 ratio because the silica and the coupling agent formed strong linkages and aggregates inside the PVB. The mechanical properties (tensile strength and hardness) of the composites were also investigated. The main challenge is improving the non-woven durability and mechanical properties of the prepared nanocomposites. The results show the best ratio of SiO2, which improved the thermal stability of PVB was 3% in the presence of a coupling agent with a weight residue 53.35%. Thermogravimetric analysis (TGA) was performed for the treated non-woven polyester. The most thermally stable sample was PVB/1% SiO2.