Utjecaj nanočestica cinkova oksida na strukturu i svojstva mješavine poli(vinil-alkohola) i hitozana

Nanocomposites encompass a large variety of materials made of distinctly dissimilar components and mixed on a nanometer scale. Their properties depend not only on the properties of their constituents, but also on their morphology and interfacial characteristics. This research was conducted on films made of nanocomposites with antimicrobial activity. Organic nanoparticles (NPs) of chitosan and inorganic nanoparticles of ZnO, both known for their antimicrobial effect are added into a water soluble non-toxic PVA matrix. Blends of PVA and CS were chemically crosslinked with glutaraldehyde (GA). Characterization of blends was performed using dynamic-mechanical analysis (DMA), differential scanning calorimetry (DSC), scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM/EDS), atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). The influence of nanoparticles and crosslinking on the permeation of small nitrogen molecules through the obtained nanocomposite films was also investigated. Permeation was examined by the time-lag method. It was found that the dynamic modulus of elasticity and the vibration damping factor can be tailored by varying the proportion of added components. An interaction between PVA, CS and ZnO was confirmed, which allows good miscibility. Chitosan reduces crystallinity degree of PVA, and hydrogen bonds are formed between PVA and CS. The addition of ZnO to the polymer matrix reduces the intensity of α relaxation in the mechanical spectrum, which indicates a good connection and the formation of an interphase with reduced molecular mobility at the interface with the polymer matrix. The addition of CS and ZnO to PVA improves barrier properties.