Polymer-based nanocomposites have been broadly investigated to improve its specific properties such as thermal and mechanical properties to use in different application areas. In this study, we aimed to ameliorate the desired physical properties of polyvinyl butyral (PVB) by introducing various amounts of silver (Ag) and cobalt (Co) nanoparticles (NPs) in the polymer matrix. The arc-discharge method submerged in liquid nitrogen was performed to synthesize the metal NPs. To produce hybrid nanocomposites, we demonstrated embedding Ag:Co nanoparticles in the PVB matrix via easy/low-cost solution casting process without any additional materials. In the results of analysis for nanocomposites, it was observed that there were improvements in thermal, mechanical and microwave absorption characteristics of the PVB polymer with interaction of NPs with the polymer. As a result of these interactions, the hybridization of PVB with the metal NPs resulted in the improved thermal stability since the glass transition temperature was increased from 45.6 to 55.1 degrees C. Besides, while the tensile strength (sigma) of the bare PVB film was calculated as 20.52 MPa, the strength of the corresponding tensile strength (sigma) of 1.0 wt.% Ag:Co nanocomposite film was improved to 43.41 MPa. Moreover, in order to determine the effect of these changes on the radar absorption feature of nanocomposites, one-dimensional A-Scan measurements were performed on 2-18 GHz frequency band. In the results, it was observed that 1.0%.wt Ag:Co nanocomposite film absorbed approximately 90% of the incoming energy. The characterization results revealed that a positive synergetic effect raised in the case of the modification of the PVB matrix with both Ag and Co NPs. In the light of these data, it was understood that the characteristics of PVB were improved with the NPs combining, and the usage area of that will also increase thanks to this improvement. These regenerated properties made the hybrid nanocomposite a promising substrate material with considerable potential applications for various transparent, flexible, and portable surface coatings.