Chitosan comprises polymeric macromolecules with technical and biological properties that have been used in biomedical healing applications requiring anti-microbial and anti-inflammatory capacities worldwide. In the tropical regions, green banana peel extract and andiroba oil are considered natural products with wound healing properties. The present study, for the first time, synthesized chitosan/green banana peel extract/andiroba oil (CGA) membranes and analyzed them using scanning electron microscopy (SEM) and the swelling and moisture tests. The CGA membranes together with control membranes of plain chitosan and chitosan plus green banana peel extract, were characterized by contact angle measurement, X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Macroscopic analysis showed significant differences in color and transparency caused by the number of decoction days used for extract preparation and the oil content. SEM observations disclosed the formation of two phases, lipid and polymer, in the CGA. The number of decoction days and the andiroba oil content were inversely related to the swelling moisture uptake. All membranes were found to be hydrophilic with contact angles less than 90°. The incorporation of plant extract and oil promoted the appearance of related XRD peaks. DSC curves revealed a reduction in the enthalpy of the CGA membranes compared with plain chitosan, which might be attributed to the evaporation of the natural extract and oil. Based on these findings, the studied newly synthesized membranes demonstrated a potential for healing epithelial lesions.

The increasing use of petroleum plastics has caused environmental damage due to the degradation time of these materials. An alternative to petroleum plastics could be thermoplastic starch (TPS). However, thermoplastic starch does not exhibit satisfactory tensile properties. The mechanical properties of thermoplastic starch can be improved by adding sisal microfibers. Thus, the objective of this study was to evaluate the influence of different levels of glycerol and sisal microfibers on the thermal and tensile properties of thermoplastic corn starch composites. The microfibers were obtained via mechanical treatment followed by chemical treatment (alkaline treatment and bleaching). The films were obtained by the casting method using commercial corn starch and glycerol as a plasticizing agent, reinforced with sisal microfibers. Fourier transform infrared spectroscopy (FTIR) results revealed that the addition of microfibers did not change the chemical structure of the TPS matrix. The films from the samples with 18% glycerol and 10% microfibers had the highest value for the maximum tension, equal to 4.78 MPa. The thermal decomposition profile of TPS was not altered by the addition of microfibers. Our findings demonstrated the profound influence of glycerol and microfiber contents on the tensile properties of thermoplastic starch composites.

O minério de ferro é essencial para a obtenção dos aços, os quais são materiais amplamente utilizados em nossa sociedade. No Brasil as principais reservas mineralógicas associadas aos depósitos de ferro estão localizadas na província mineral de Carajás, situada no estado do Pará. Este estudo apresenta para o minério obtido na província de Carajás, uma revisão de suas características gerais como: ocorrência, alteração, composição, propriedades físicas e aplicações. Por meio de dados da literatura foi observado que a hematita, magnetita e goethita estão presentes no minério de ferro encontrado na província de Carajás. Diante do exposto, esta investigação exibe informações úteis com potencial benefício para o setor mineral e industrial.

Currently, petroleum-derived plastics are widely used despite the disadvantage of their long degradation time. Natural polymers, however, can be used as alternatives to overcome this obstacle, particularly cornstarch. The tensile properties of cornstarch films can be improved by adding plant-derived nanofibers. Sisal (Agave sisalana), a very common low-cost species in Brazil, can be used to obtain plant nanofibers. The goal of this study was to obtain sisal nanofibers using low concentrations of sulfuric acid to produce thermoplastic starch nanocomposite films. The films were produced by a casting technique using commercial corn starch, glycerol, and sisal nanofibers, accomplished by acid hydrolysis. The effects of glycerol and sisal nanofiber content on the tensile mechanical properties of the nanocomposites were investigated. Transmission electron microscopy findings demonstrated that the lowest concentration of sulfuric acid produced fibers with nanometric dimensions related to the concentrations used. X-ray diffraction revealed that the untreated fibers and fibers subjected to acid hydrolysis exhibited a crystallinity index of 61.06 and 84.44%, respectively. When the glycerol and nanofiber contents were 28 and 1%, respectively, the tensile stress and elongation were 8.02 MPa and 3.4%. In general, nanocomposites reinforced with sisal nanofibers showed lower tensile stress and higher elongation than matrices without nanofibers did. These results were attributed to the inefficient dispersion of the nanofibers in the polymer matrix. Our findings demonstrate the potential of corn starch nanocomposite films in the packaging industry.

Currently, more effective methods in the area of food preservation have been improved in recent years. In this context, active packaging can be highlighted, which interacts directly with food to increase its shelf life. In this scenario, the present study manufactured nanocomposite films (NC) of arrowroot starch, carboxymethylcellulose (CMC), and zinc oxide nanoparticles (ZnO NPs) in different contents (0%, 0.5%, 2%, and 5% w/w) for bread packaging. The films were obtained using the solvent casting method and evaluated for water vapor permeation, tensile properties, thermal properties, transparency, biodegradation in soil, and application as bread packaging. Our findings demonstrated that the addition of 5% ZnO NPs in thermoplastic arrowroot starch/CMC films (TPA‐CMC/ZnO‐5.0) promoted an increase in tensile strength and modulus from 1.75 to 35.84 and 5.79 to 1142.29 MPa, respectively. After 20 days of soil burial, total degradation was observed in all the films. During 9 weeks of using the films as bread packaging, no macroscopic changes characteristic of colonization by microorganisms were observed. Thus, our findings demonstrate that TPA‐CMC/ZnO‐5.0 films increased the shelf life of the bread and can be used satisfactorily as active packaging for bread.