RESUMO
In this study, poly(vinyl alcohol) (PVA) membranes containing Ag nanoparticles (AgNPs) were prepared by electrospinning and grafted copolymerization with 3,3',4,4'-benzophenone tetracarboxylic acid (BPTA) to provide better mechanical properties, lower water vapor transmittance, and higher antibacterial activity (against Staphylococcus aureus and Escherichia coli) than the PVA/AgNPs membrane. The PVA/AgNPs/BPTA membrane showed higher antibacterial activity than the other membranes, and it produced inhibition zones with diameters of 18.12 ± 0.08 and 16.41 ± 0.05 mm against S. aureus and E. coli, respectively. The PVA/AgNPs/BPTA membrane was found to be capable of promoting reactive oxygen species (ROS) formation under both light and dark conditions. Cycling experiments performed following ROS quenching showed that the best-performing composite membrane retained >70% of its original OHâ radical and H2O2 charging capacity after seven cycles. In the filtration test, the electrospun nanofibrous membranes showed high filtration efficiencies of 99.98% for sodium chloride (NaCl). In addition, these membranes maintained a relatively low pressure drop of 168 Pa with a basis weight of 2.1 g m-2. Thus, the PVA/AgNPs/BPTA membrane was concluded to be a promising medical protective material offering the benefits of structural stability and reusability.
RESUMO
In this study, we prepared corn starch (CS) and papaya polysaccharide (PPs) films using the solution casting technique. A Box-Behnken experimental design was used to determine the effect of ethanol concentration, extraction duration, and material concentration during PPs extraction. The resulting films were characterized in terms of structural changes, physical, optical, mechanical, Fourier-transform infrared (FTIR) spectroscopy, and thermal properties. The results show that PPs-CS composite films have good antioxidant and moisturizing properties and general antibacterial performance. These results revealed that after adding PPs, the films exhibited a significant increase in swelling and tensile strength, while depicted a reduction in thickness, transparency, and solubility. SEM images revealed that PPs and CS are highly compatible; moreover, FTIR spectroscopy showed that intermolecular hydrogen bonding existed between CS and PPs, forming a compact film structure. Finally, the incorporation of PPs and CS influenced the shelf-life of fresh cut apples, with the edible film incorporated with PPs positively improving sensory acceptance of combined materials.