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Solution blow spinning (SBS) is used to make poly(butylene-adipate-co-terephthalate) (PBAT) and poly(vinylpyrrolidone) (PVP) blend nanofibers and study the effect of process parameters on their formation. A [3.sup.4-1] fractional factorial statistical model with three levels and four factors was applied. The factors included the concentration of PVP (wt%) in the PBAT polymer matrix, pressurized air pressure (psi), working distance (cm), and feed rate (ml [h.sup.-1]). The linear and quadratic effects were analyzed using a Pareto chart and verified in a well-adjusted response surface model. The PVP concentration and working distance had a significant effect on the production of nanofibers. The nanofibrous mats were evaluated by scanning electron microscopy (SEM) and had a mean diameter ranging from 164 to 656 nm. A higher concentration of PVP and a shorter working distance resulted in lower mean fiber diameter. In addition, X-ray diffraction revealed an increase in the degree of crystallinity of the nanofibrous PBAT due to a greater degree of packing among the polymer molecules. However, the addition of PVP to the polymer matrix is associated with a reduction in the degree of crystallinity of the nanofibrous mat. KEYWORDS aromatic copolyester, nanofibers, poly(butylene-adipate-co-terephthalate), poly (vinylpyrrolidone), statistical analysis, 1 | INTRODUCTION The study and production of nanofibers are being increasingly focused on because of the versatility of applications enabled by the greater surface area and nanoscale porosity of [...]

The objective of this work was to evaluate the effect of three silane coupling agents with different aliphatic chain lengths on the hydrophobicity of eucalyptus pulp fiber. The three silanes coupling agents used (isobutyltrimethoxysllane, methyltrimethoxysilane, and n-octyltriethoxysilane [OTES]) were each tested at three concentrations. Scanning electron microscopy coupled with energy dispersive spectroscopy revealed that the silane coupling agents markedly increased the Si content of the treated fibers. The Si distribution was not completely homogenous but was abundant in the treated samples. The treated fibers had higher contact angles for water and lower moisture adsorption than the control. Of the coupling agents tested, OTES treated fibers had the highest moisture resistance. This was likely due to the greater chain length of the aliphatic side group coupled to OTES. The use of silane coupling agents with alkyl side chains could improve the functional properties of pulp fiber and increase its compatibility with hydrophobic polymers., INTRODUCTION The use of plant fibers in developing new and inexpensive reinforced composite materials has been recently emphasized [1-3]. Composites made with plant fibers have outstanding mechanical properties and they [...]

Ora‐pro‐nobis mucilage (MOPN) was incorporated into starch films to improve their mechanical, chemical, and retrogradation properties. Films were made in four MOPN content (0%, 10%, 20%, and 30%) by casting. Films with added MOPN presented antioxidant capacity varying from 3.9% to 23.3%. Chemical cross‐links between starch and MOPN were observed in Fourier transform infrared spectroscopy (FTIR) spectrum, resulting in a reinforced network with the greater young modulus (0.02 Pa, control‐film, to 2.20 Pa, 30%‐MOPN), higher tensile strength (1.34 Pa, control‐film, to 4.38 Pa, 30%‐MOPN), and reduction in elongation (250.32%, control‐film, to 6.55%, 30%‐MOPN). Water vapor permeability did not differ statistically between films. In assays photodegradation, higher MOPN content exhibited less shrinkage of films over time and more loss mass in films during 28 days. FTIR spectrum showed that the films increased crystalline regions during storage, which resulted in stronger aggregation between aligned helices. In addition, water molecules were released which allowed a better alignment of the starch chains. Starch‐based films added MOPN can alternatively be used as active biodegradable packaging since it is able to form cohesive, flexible films and with antioxidant action. Furthermore, MOPN, especially 30% addition, reduces drastic changes in mechanical properties over time. [ABSTRACT FROM AUTHOR]

The effective control of an insect pest such as Drosophila suzukii (Diptera: Drosophilidae) has been challenging because its attack on red fruits can cause losses in production of up to 80% worldwide. The objective of this work was to extract and characterise the essential oil from rosemary (Rosmarinus officinalis), produce and characterise nanoparticles incorporated with this essential oil, evaluate the in vivo insecticide activity of free and nanoencapsulated essential oil against D. suzukii, and evaluate the effect of that oil on the enzyme acetylcholinesterase. The nanoparticles produced with the essential oil from rosemary had a particle size and surface charge of 236.6 nm and −11.8 mV, respectively. According to the FTIR data, the essential oil was incorporated into the polymeric matrix of poly(ε‐caprolactone). Through in vivo toxicity analysis, the free and nanoencapsulated essential oils were found to possess insecticidal activity, with an LD50 close to 9.1 g/L. The maximum anticholinesterase activity for the essential oil was 75% at a concentration of 0.10 mg/mL. The incorporation of the essential oil from R. officinalis into biodegradable nanoparticles of poly(ε‐caprolactone) potentiated and prolonged its in vivo insecticidal activity against D. suzukii. [ABSTRACT FROM AUTHOR]

Food contamination by mycotoxigenic fungi is one of the principal factors that cause food loss and economic losses in the food industry. The objective of this work was to incorporate the essential oil from Corymbia citriodora Hook and its constituents citronellal and β-citronellol into poly(lactic acid) nanofibers; to characterize the nanofibers by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy and differential scanning calorimetry; to evaluate the antifungal activity by the fumigation method; to evaluate the antimycotoxigenic activity against Aspergillus carbonarius, Aspergillus ochraceus, Aspergillus westerdijkiae, Aspergillus flavus, and Aspergillus parasiticus; and to evaluate the morphology of these microorganisms. All the nanofibers had a regular, smooth, and continuous morphology. FTIR analyses confirmed that the active ingredients were incorporated into the polymer matrix. All samples exhibited antifungal and ochratoxigenic inhibitory activities of up to 100% and 99%, respectively, with the best results observed for (PLA + 30 wt% β-citronellol) nanofibers and (PLA + 30 wt% citronellal) nanofibers. However, 100% inhibition of the production of aflatoxin B1 and B2 was not observed. The images obtained by SEM indicated that the nanofibers caused damage to the hyphae, caused a decrease in the production of spores, and caused deformation, rupture, and non-formation of the conid head, might be an alternative for the control of mycotoxigenic fungi., (© The Author(s) 2024. Published by Oxford University Press on behalf of FEMS.)

Chitosan is a polysaccharide composed of randomly distributed chains of β-(1-4) D-glucosamine and N-acetyl-D-glucosamine. This compound is obtained by partial or total deacetylation of chitin in acidic solution. The chitosan-based hemostatic agents have been gaining much attention in the management of bleeding. The aim of this study was to evaluate in vitro hemagglutination activity of chitosan nanoparticles using human erythrocytes. The preparation of nanoparticles was achieved by ionotropic gelification technique followed by neutralization with NaOH 1 mol/L(-1). The hemagglutination activity was performed on a solution of 2% erythrocytes (pH 7.4 on PBS) collected from five healthy volunteers. The hemolysis determination was made by spectrophotometric analysis. Chitosan nanoparticle solutions without NaOH addition changed the reddish colour of the wells into brown, suggesting an oxidative reaction of hemoglobin and possible cell lysis. All neutralized solutions of chitosan nanoparticles presented positive haemagglutination, without any change in reaction color. Chitosan nanoparticles presented hemolytic activity ranging from 186.20 to 223.12%, while neutralized solutions ranged from 2.56 to 72.54%, comparing to distilled water. Results highlight the need for development of new routes of synthesis of chitosan nanoparticles within human physiologic pH.