Synthesis, characterization and applications of poly(vinyl chloride) nanocomposites loaded with metal oxide nanoparticles

Metal oxide (i.e., Fe₂O₃, ZnO and TiO₂) nanoparticles (NPs) have been prepared and investigated by various techniques with the objective of synthesis of nanocomposites thin films based on poly(vinyl chloride) (PVC) as a matrix. Different loadings of metal oxide NPs (i.e., 2.0, 5.0, 10.0 and 15.0 wt%) were incorporated in PVC followed by solution casting. The prepared film samples were characterized by X-ray diffraction (XRD), Raman spectra, scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), thermal and electrical measurements. Also, the antibacterial activity was tested against Gram-positive (i.e., Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (i.e., Escherichia coli and Pseudomonas aeruginosa). The results were discussed in relation to metal oxide NPs content and type. XRD of the prepared nanocomposite films was almost the same as that of mixed ZnO metal oxide NPs with an amorphous region of PVC. Raman spectra suggested that ZnO NPs were just physically inserted into PVC matrix. SEM revealed a homogeneous distribution of the NPs on using 10 wt% in PVC matrix, while the NPs agglomerations at higher content (i.e., 15 wt%) were formed. The dynamic mechanical results, as a function in temperature, indicated an increase in the storage and loss moduli and a decrease in loss factor tan δ with shifting to higher glass transition temperature, with increasing metal oxide NPs content up to 10 wt%. Thermal gravimetric analysis revealed that utilizing Fe₂O₃ and TiO₂NPs in PVC matrix improved thermal stability of PVC in comparison with ZnO NPs with catalytic behavior and polymer decomposition acceleration. Metal oxide Nps increased the electrical conductivity of PVC, the electrical conductivity values were found to be in the order of 10⁻¹³ for ZnO, while it is in the order of 10⁻¹¹ for Fe₂O₃ and TiO₂. This finding is highly recommended such composites to be used in antistatic applications as the needed range for such application is 10⁻⁹–10⁻¹⁴Ω⁻¹ cm⁻¹. Metal oxide nanocomposites improved the antibacterial activity of PVC toward both types of bacteria and can be used as an effective antibacterial agent in biomedical healthy applications.