CONCLUSIONS 1-The NbC nanoparticles is aggregated as a cluster at lower concentrations. At high concentrations of NbC nanoparticles, the nanoparticles form a paths network inside the (PVA-PAA) blend. 2-The inhibition zone for S. aureus increases with increase in concentrations of NbC nanoparticles. 3-The (PVA-PAA-NbC) nanocomposites have good antibacterial activity against Staphylococcus aureus.