Salih Birhanu Ahmed

The growing demand for sustainable food packaging materials has accelerated the development of biodegradable alternatives to conventional petroleum-based plastic. This study investigates the reinforcement of electroblown gelatin/polyvinyl alcohol (G-PVA) nanofibrous mats with kombucha-derived bacterial cellulose nanowhiskers (BCNWs) to enhance their mechanical, thermal, and surface properties while promoting the valorization of symbiotic culture of bacteria and yeast (SCOBY) waste. BCNWs were incorporated into the G-PVA matrix at different loadings, and the resulting nanocomposites were characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), tensile testing, and water contact angle measurements. The addition of BCNW significantly improved the tensile strength of the nanofibrous mats, with a maximum increase about 120% compared with neat G-PVA nanofibers. SEM images revealed uniform, bead-free fiber structures at appropriate BCNW concentrations, while FTIR and XRD analyses confirmed effective interactions between the nanowhiskers and the polymer matrix. TGA results indicated enhanced thermal stability at moderate BCNW loadings, whereas excessive BCNW content promoted agglomeration and reduced thermal resistance. Furthermore, the incorporation of BCNWs increased the water contact angle to 144.11 ± 1.45°, demonstrating improved surface hydrophobicity. Overall, kombucha-derived BCNWs effectively reinforced electroblown G-PVA nanofibers, producing biodegradable nanocomposite mats with improved performance and strong potential for sustainable food packaging applications.

Developing biodegradable and functional polymeric materials for active food packaging is essential to mitigate the environmental burden of petroleum-based plastics. In this context, gelatin/chitosan (G–Ch) nanofibrous mats were fabricated via solution blow spinning (SBS) and functionalized with snail slime (SS) and Pinus sylvestris essential oil (PSEO) to enhance their bioactivity and barrier performance. SS is rich in glycoproteins and natural bioactive compounds, while PSEO is characterized by terpene-based antimicrobial and antioxidant activities. SS and PSEO were incorporated into the G–Ch polymeric matrix to enhance the bioactivity, structural functionality and preservation performance of the nanofibrous mats. Three formulations (G–Ch, G–Ch–SS, and G–Ch–SS–10PSEO) were designed to elucidate the influence of snail slime and essential oil incorporation on the structure–property–function relationships of the nanofibrous mats. Morphological analysis revealed a smooth and bead-free fibrous structure across all formulations. The average fiber diameter (AFD) increased from 191.83 nm for G–Ch to 263.88 nm for G–Ch–SS and 295.83 nm for G–Ch–SS–10PSEO. FTIR and XRD analyses showed the physical encapsulation of the active compounds without significant chemical interactions. Furthermore, the incorporation of PSEO increased surface hydrophobicity and reduced air permeability, indicating the formation of a more compact fibrous structure with enhanced barrier properties. The functional performance of the nanofibrous mats was significantly improved by the addition of snail slime and PSEO. The G–Ch–SS–10PSEO formulation exhibited the highest antioxidant activity, reaching 36.8% for DPPH and 42.7% for ABTS, along with enhanced antibacterial efficacy against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Application tests on chicken wings demonstrated that the bioactive nanofibers effectively suppressed microbial growth, limited pH increases, and reduced lipid oxidation during 14 days of refrigerated storage. Overall, the results demonstrate that the synergistic integration of snail slime and essential oil within a biodegradable polymer matrix provides a promising strategy for designing active nanofibrous materials with enhanced structural and bioactive properties for sustainable food-packaging applications.

The increasing demand for sustainable, antibacterial, and eco-friendly food packaging materials has intensified research into biodegradable biopolymers with enhanced functional properties. In this study, gelatin–chitosan-based nanofibers were fabricated via electro-blowing and reinforced with cellulose microcrystals (CMC) extracted from corn cobs via acid hydrolysis. The formulation (12% gelatin and 3% chitosan) and electro-blowing parameters were optimized based on previous literature and preliminary trials to ensure uniform fiber morphology. CMC was incorporated at concentrations of 1, 3, and 5% (w/w), and the resulting nanofibers were characterized using FE-SEM, ATR-FTIR, XRD, TGA, and air permeability tests. SEM analysis revealed smooth, bead-free fibers with average diameters ranging from 642.19 ± 40.36 nm (control) to 760.05 ± 32.64 nm (3% CMC), confirming the impact of filler loading. XRD results demonstrated an increase in crystallinity from 21.3% in the control to 27.8% with 5% CMC. At the same time, TGA indicated enhanced thermal stability at low CMC concentrations, with a maximum decomposition temperature of 326 °C for 1% CMC compared to 315 °C in the control. However, higher loadings (5% CMC) led to slight thermal deterioration, likely due to disruptions in polymer chains. These results confirm that corncob-derived CMC can be successfully integrated into gelatin–chitosan nanofibers to improve structural and thermal properties, positioning them as promising candidates for active food packaging. Future studies will focus on mechanical and antibacterial performance to further validate their practical application.

The study aims to manufacture composite fibrous media using a combination of Polypropylene (PP)–Polylactic Acid (PLA)–Zinc Stearate (ZnSt) (75PP-25PLA-ZnSt) Melt-Blown (MB) as a substrate, and Electrically Assisted Solution Blow Spun (ESBS) Gelatin (G-12120) nanofibrous webs were collected on the substrate surface. The gelatin nanofibrous webs fabricated by ESBS are designated as NF, while those from MB 75PP-25PLA-ZnSt fabrics are labeled as MF. Herein, NF/MF and MF/NF/MF layered nonwoven fabrics are fabricated to filter PM[ ] aerosols from the aerosol-polluted environment. The fabricated filter samples were characterized morphologically using a Scanning Electron Microscope (SEM), air permeability, surface wetting characteristics, and aerosol filtration performance. The results demonstrated that the successfully produced composite filter membrane exhibited relatively smooth morphological structures with mean fiber diameters of [ ] and [ ] nm from the ESBS and melt-blowing processes, respectively. NF/MF-5 double-layer composite filter membrane has a Quality Factor (QF) of 0.05[ ]Pa[ ]. This filter sample also exhibits a high air permeability of 185[ ]mm/s and a filtration efficiency of 78.36%. Therefore, this research provides a new insight showing that composite membranes with high filtration performance made from biodegradable polymers could be utilized for creating an eco-friendly environment.

This study investigates the impact of rare elements on high-entropy alloys (HEAs) and provides significant insights. By integrating varying proportions of Al-Nd and Al-Ce compounds into a CoCrFeNi-based alloy, shifts were detected in the microstructure and phase composition of grains. As the proportion of rare elements rose, their localization within the grain phase structure intensified, leading to overall coarsening. The heat transfer characteristics of HEA alloys containing rare elements exhibited variability, with notable phase transitions occurring at cryogenic temperatures based on the alloying constituents. Among the tested alloys, Ce10 and Ce20 alloys demonstrated the highest heat transfer rates (800[ ][ ]). Notably, an escalation in the rare element ratio added to the alloy resulted in a significant augmentation in hardness, nearly doubling the original level.