Optical, thermal, and structural properties of polyurethane in Mg-doped zinc oxide nanoparticles for antibacterial activity

This study pertains to the different contents (0, 1, 2.5, and 5%) of 0.010-M magnesium-doped zinc oxide nanoparticles (MgZnO NPs) incorporated into the polyurethane (PU) polymer matrix. The prepared MgZnO NPs/PU composite films were characterized by UV-vis DRS, FT-IR, TGA, DSC, and SEM analyses. The UV-vis DRS spectral analysis clearly exhibited the composite film absorption peaks at 280 and 366 nm. The FT-IR spectral analysis clearly exhibited MgZnO NPs corresponding to 562 cm(-1). The optical transmittance of the PU films decreased with increasing MgZnO NP content. The TGA analysis of the composite films indicated a higher weight loss when compared to the pure PU film. The SEM images confirmed the presence of MgZnO NPs embedded in the PU matrix. The prepared composite films were tested for antibacterial activity against the gram-negative (Escherichia coli DH5 alpha) bacterial strain. The effect of the antibacterial rate of the composite films indicated 0%, 67.6%, 73.5%, and 93.3%. However, the physicochemical properties and antibacterial activities were highly dependent on the changes in the chemical and morphological structure and increased the content of MgZnO NPs in the composite films. We believe that the effect of Mg doping could enhance the antibacterial activity of ZnO NPs for the E. coli DH5 alpha strain. The bactericidal ability of MgZnO NPs/PU composite films can be useful for food packaging applications and can extend the shelf life of agricultural products.