In this study, thin, polymeric films consisting of poly(vinyl alcohol) (PVA) and chitosan (Ch) with the addition of poly(hexamethylene guanidine) (PHMG) were successfully prepared. The obtained materials were analyzed to determine their physicochemical and biocidal properties. In order to confirm the structure of PHMG, nuclear magnetic resonance spectroscopy (¹H NMR) was applied, while in the case of the obtained films, attenuated total reflectance infrared spectroscopy with Fourier transform (FTIR-ATR) was used. The surface morphology of the polymer films was evaluated based on atomic force microscopy. Furthermore, the mechanical properties, color changes, and thermal stability of the obtained materials were determined. Microbiological tests were performed to evaluate the biocidal properties of the new materials with and without the addition of PHMG. These analyses confirmed the biocidal potential of films modified by PHMG and allowed for comparisons of their physicochemical properties with the properties of native films. In summary, films consisting of PVA and PHMG displayed higher antimicrobial potentials against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria in comparison to PVA:Ch-based films with the addition of PHMG.

‘Gouda cheese’ is one of the most popular varieties of cheese eaten worldwide. The preservation problem of gouda arises due to microbial contamination and infestation. Therefore, essential oil (EO) based PVP-CMC-BC-GG hydrogel film was prepared to solve the problem and to extend the shelf-life of ‘Gouda cheese’. Anthocyanin (isolated from red cabbage) based pH stickers are integrated into the packaging system to recognize the spoilage of ‘cheese’. EOs (clove and/or cinnamon) are added to PVP-CMC-BC-GG hydrogel film to improve its antimicrobial, physical, mechanical, and thermal properties as well as shelf-life of cheese. The films are assessed based on their physical, structural, and functional properties, real-time assessment on cheese, and biodegradability. The results revealed that although the addition of oils to the PVP-CMC-BC-GG hydrogel films enhanced its mechanical, hydrophobic, and antimicrobial properties, the biodegradability of PVP-CMC-BC-GG films declined with the addition of EOs. The thermal properties remained the same irrespective of the addition of EOs. The shelf life of cheese was extended for more than 10–12 days, inside the PVP-CMC-BC-GG hydrogel sachet compared to the conventional PE packaging system. Hence the use of the PVP-CMC-BC-GG sachet (containing EO or without EO) is recommended for cheese packaging along with the use of PVP-CMC-BC-GG anthocyanin bio stickers for monitoring the quality of cheese.

This study explores the feasibility of modifying the surface liquid spraying method to prepare porous bioscaffolds intended for wound dressing applications. For this purpose, gentamicin sulfate was loaded into polylactide-polyvinyl alcohol bioscaffolds as a highly soluble (hygroscopic) model drug for in vitro release study. Moreover, the influence of inorganic salts including NaCl (10 g/L) and KMnO₄ (0.4 mg/L), and post-thermal treatment (T) (80 °C for 2 min) on the properties of the bioscaffolds were studied. The bioscaffolds were characterized by scanning electron microscopy, Fourier Transform infrared spectroscopy, and differential scanning calorimetry. In addition, other properties including porosity, swelling degree, water vapor transmission rate, entrapment efficiency, and the release of gentamicin sulfate were investigated. Results showed that high concentrations of NaCl (10 g/L) in the aqueous phase led to an increase of around 68% in the initial burst release due to the increase in porosity. In fact, porosity increased from 68.1 ± 1.2 to 94.1 ± 1.5. Moreover, the thermal treatment of the Polylactide-polyvinyl alcohol/NaCl (PLA-PVA/NaCl) bioscaffolds above glass transition temperature (T_g) reduced the initial burst release by approximately 11% and prolonged the release of the drug. These results suggest that thermal treatment of polymer above T_g can be an efficient approach for a sustained release.

This study investigates antibacterial polymer composites based on polypropylene as modified by caraway essential oil at various concentrations, the latter immobilized on a talc. The caraway essential oil is incorporated in the polypropylene by a thermoplastic processing method. Analysis of the morphology of the composites was carried out by scanning electron microscopy. The chemical composition of the caraway essential oil in addition to its efficiency of incorporation and release were evaluated by GC/MS and Pyrolysis-GC/MS techniques, respectively. Determination was made as to the influence of such incorporation on thermal and tensile properties of the samples, while antibacterial activity was evaluated through conducting disk diffusion tests and measurement with adherence to the ISO 22196:2011 standard. It was found that incorporating the caraway essential oil in the samples did not affect the homogeneity of the thermoplastic-processed composites at any studied concentration. Stress–strain analysis confirmed the plasticizing effect of the essential oil in the polypropylene matrix, in addition to which, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) analysis revealed that the prepared compositions with essential oil exhibited similar thermal properties to neat polypropylene. Results indicated significant antibacterial activity against Staphylococcus aureus and Escherichia coli at the concentration of essential oil of 4.9 ± 0.2 wt% and higher.