Search Results (245)

This work evaluated the effect of coffee oil epoxide (COE), produced from coffee waste, on thermal, mechanical, barrier, and exudation resistance properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/natural rubber (PHBV/NR) blends. Building upon previously published 0.3% COE results, this study examined 0.4% and 0.75% concentrations to optimize performance. Thermal analysis revealed that COE incorporation significantly enhanced chain mobility, with glass transition temperature depressions of 6.1 °C and 7.4 °C for 0.4% and 0.75% COE formulations, respectively, compared to unplasticized PHBV/NR blends. Crystallinity decreased from 54.5% (PHBV/NR) to 52.6% and 51.9% with increasing plasticizer concentration, while melting temperatures decreased by 3.9% and 4.9%, confirming improved polymer chain mobility. Mechanical properties demonstrated COE’s plasticizing effectiveness, with tensile strength decreasing by 13.3% (0.4% COE) and 16.2% (0.75% COE) compared to PHBV/NR blends. Young’s modulus similarly decreased by 21.0% and 24.0%, while elongation at break improved slightly with increasing COE content. Barrier properties improved substantially across all concentrations: water vapor transmission rates decreased from 4.05 g/m²·h (PHBV/NR) to 1.55 g/m²·h (0.3% COE) and 0.67 g/m²·h for 0.4% and 0.75% COE, attributed to COE’s hydrophobic nature. SEM morphological analysis confirmed improved phase compatibility at 0.40% COE, with reduced rubber droplet size and homogeneous surface morphology. Exudation testing revealed excellent retention (0.21–0.53 wt% loss over 63 days). Results indicate 0.40% COE as optimal, achieving superior barrier properties while maintaining mechanical performance for sustainable packaging applications. Full article

Background/Objectives: One-dose packaging is beneficial for older adults and those on multiple medications because it ensures that no doses are missed and supports medication adherence. However, conventional one-dose packaging materials have high moisture permeability, making them unsuitable for the storage of hygroscopic medications. We evaluated the barrier performance of food packaging materials against moisture and oxygen and investigated their potential to enhance the physical stability of the highly hygroscopic sodium valproate, under stressed storage conditions. Methods: Barrier performance was evaluated by measuring the water vapor transmission (WVTR) and oxygen transmission rates of each packaging material. Then, we evaluated the stability of sodium valproate tablets in different food packaging films by measuring weight change, breaking force, and visual appearance over 14 days under stressed storage conditions (35 °C and 75% relative humidity). Conventional cellophane-laminated polyethylene was used as the reference. Results: The WVTR of the food packaging films were below 2 g/m²/day, less than that of the conventional material. Tablets stored in Materials A and B showed weight increases of no more than 1.2% after 3 days, whereas the maximum increase among all food films was 3.7% (Material C). For Materials A and B, the breaking force remained measurable and the visual appearance unchanged throughout the 14-day period, whereas Material C became unmeasurable by day 14. Tablets packaged in cellophane-laminated polyethylene exhibited deliquescence, with visible deformation and stickiness within 3 days, rendering them unmeasurable. Conclusions: Food packaging materials with high barrier performance offer a practical, safe, and effective solution for one-dose packaging of hygroscopic medications, potentially expanding their clinical use and improving adherence. Full article

Soybean wax is a sustainable alternative to synthetic polymeric coatings in packaging due to its renewable, environmentally benign, and hydrophobic properties. In order to be effectively applied, however, soybean wax must be emulsified in water. The present work compares two stabilization approaches for soybean wax emulsions: a conventional surfactant-based emulsion (SE) using a mixture of nonionic surfactants (Span-80 and Tween-80), and a Pickering emulsion (PE) using cellulose nanocrystals combined with sodium alginate (CNC-SA) as an anionic stabilizer. The SE produced stable emulsions at 6 wt% Span-80/Tween-80 (at a HLB_mix value of 10) with a mean droplet size of 449 nm but limited storage stability (approximately 7 days under ambient conditions), while the PE achieved superior stability (approximately 1 month) at 1 wt% CNC-SA with a mean droplet size of 740 nm. The stabilized SE and PE were subsequently applied as coatings on three different types of paper substrates: northern bleached kraft (NBK) paper, copy paper, and cellulose nanofiber (CNF)-coated NBK paper. When applied to northern bleached kraft (NBK) paper, the SE coatings provided minimal improvements in barrier performance. The Cobb 60 value decreased slightly from 125 g/m² (control-no coating) to 86 g/m², indicating a negligible water barrier with immediate water absorption upon contact. In contrast, the Cobb 60 value of the PE-coated NBK paper decreased markedly from 125 g/m² to 39 g/m², confirming that the PE coating substantially enhances water resistance. The SE coating displayed a significant loss of water contact angle (WCA) from 85° to 0° within 20 s, showing limited water holdout capacity, whereas PE-coated NBK paper demonstrated strong water holdout, with the WCA decreasing only from 94° to 85° over 5 min. The SE coating achieved only a 14% reduction in water vapor transmission rate (WVTR), while the PE coating provided a greater reduction of 30%. In terms of oil resistance, both emulsion systems significantly enhanced the kit rating of the papers tested, e.g., from kit number 0 to 6–9 (paper dependent). The SE coating, however, experienced a substantial reduction in barrier integrity after folding, while the PE coating largely retained its oil barrier properties. Furthermore, the SE coating reduced the tensile strength of NBK paper by 41%, whereas the PE coating reduced it by only 7%. Overall, the comparative findings indicate that although the SE generated a smaller mean particle size, it offered minimal improvement in the water and oil barrier performance of paper and had a limited storage life. In contrast, the PE generated a larger mean particle size, but provided substantially greater water and oil resistance, and enhanced mechanical strength retention. In addition, the PE displayed an effective storage life of at least one month. The Pickering emulsion, formulated with all biologically derived components, therefore represents a viable, sustainable, bio-based alternative to synthetic polymeric coatings for packaging applications. Full article

Active packages have become a significant center of attention, and especially those based on biodegradable materials, due to their ability to enhance food preservation and extend shelf life. A suitable base for obtaining such types of packages has turned out to be polymers with natural origin, such as hydroxylpropyl methylcellulose (HPMC) and zein. Therefore, the present study is focused on developing films using the casting method based on pure HPMC and blends between HPMC and zein. Three types of polymer matrices were developed: pure HPMC film, HPMC 3:1 zein, and HPMC 1:1 zein. Further, all of them were loaded with curcumin to improve their biological activity, and mainly their antioxidant activity. In order to investigate the potential of these films, some of their most vital properties in terms of potential application as packaging material are established, such as mechanical properties (strain at break, Young’s modulus), barrier properties (water vapor transmission rate), and morphology. A significant change in the Young’s modulus was present after the addition of zein; it went from 276.98 ± 28.48 MPa for pure HPMC to 52.17 ± 10.19 MPa in a 1:1 ratio between the polymers. Meanwhile, strain at break showed a slight drop from 86.74 ± 8.64% to 72.44 ± 9.62%. Barrier properties were also influenced by the formation of composite film and the addition of polyphenol, lowering the water vapor transmission rate from 913.07 ± 74.01 g/m².24 h for pure HPMC to 873.05 ± 9.07 g/m².24 h for 1:1 ratio film and further to 826.35 ± 33.67 g/m².24 h after the addition of rutin to the latter. Additional characterization of radical scavenging ability towards DPPH free radicals showed a similar A-shaped trend to the values of Young’s modulus, due to the presence of hydrogen bonds, which affect both properties of the film structures. Thermal behavior and phase state investigation of the films obtained by differential scanning calorimetry prior to and after polyphenol addition was carried out, indicating full phase transition of rutin from crystalline to amorphous state. Full article

Food packaging is the largest segment of the global plastics market, yet its low degradability and limited performance in preserving perishable goods highlight the need for more sustainable alternatives. This study investigates the use of industrial softwood kraft lignin, a renewable polyol, and γ-valerolactone (GVL), an excellent green lignin solvent, to synthesize bio-based polyurethane (PU) coatings for recycled linerboard. PU was synthesized with hexamethylene diisocyanate (HDI), GVL, and 1,4-diazabicyclo[2.2.2]octane (DABCO) as a catalyst and applied to recycled linerboard (166.6 g/m²) at three coating weights: 13.5, 16.5, and 23.5 g/m². The coating enhanced water resistance, as shown by the reduced water vapor transmission rate (WVTR) and Cobb₁₈₀₀ values. Oil resistance was also significantly improved, reaching a Kit rating of 11 at the highest coating weight. Mechanical performance was maintained or enhanced, with increases in ring crush strength (RCT) and tensile index. These findings confirm the effectiveness of lignin-based PU in improving both the barrier and mechanical properties of packaging paper. Additionally, this approach presents an environmentally responsible alternative to petroleum-based coatings, adding value to lignin as a byproduct of the pulp and paper industry and supporting the transition toward more circular and sustainable packaging materials. Full article

Outdoor sportswear increasingly demands multifunctional performance, including waterproofness, breathability, and intelligent thermal regulation. Nanofiber membranes, especially those prepared via electrospinning, offer a promising platform due to their tunable pore structures, high specific surface area, and ease of functionalization. This review outlines progress from fabrication to multifunctional integration, highlighting key quantitative advances: electrospun membranes achieve water vapor transmission rates >10,000 g·m⁻²·day⁻¹ with hydrostatic pressure resistance of 80–150 kPa, and thermal conductivity as low as 0.033–0.040 W·m⁻¹·K⁻¹. We analyze how structural designs enable tailored functionalities for diverse outdoor scenarios. The review’s key contributions include establishing a clear “process-structure-function” framework, critically comparing nanofiber membranes with conventional materials, and identifying industrialization challenges—scalability, durability, cost—while pointing toward smart, sustainable, and customizable future directions. Full article

This work investigates the modification of poly(lactic acid) (PLA) film properties for food packaging applications through the incorporation of modified gelatin (Gel-mod) and a choline chloride/glycerol deep eutectic solvent (DES). PLA/Gel-mod/DES materials were melt-processed and evaluated with respect to structure, morphology, thermal and mechanical behavior, processability, wettability, barrier performance, and compostability. Two incorporation routes were investigated for adding Gel-mod into the PLA matrix: direct incorporation and masterbatch preparation. FTIR and SEM analyses confirmed improved interfacial interactions and more homogeneous dispersion when Gel-mod was directly incorporated, compared with the masterbatch route. DES acted as an effective plasticizer and nucleating agent, reducing Tg, increasing crystallinity, and enhancing processability while maintaining thermal stability. Mechanical properties decreased relative to neat PLA, primarily due to increased crystallinity and chain scission. PLA_4Gel-mod demonstrated a more balanced performance, with higher elongation at break and improved processability than the other formulations, likely due to its single processing cycle, which minimized PLA degradation. Increased hydrophilicity led to higher water vapor transmission rates, correlating with accelerated biodegradation. Overall, the synergistic incorporation of DES and gelatin provides a viable strategy to tailor PLA properties, enabling the development of compostable packaging films suitable for sustainable food contact applications. Full article

Biopolymers such as chitosan and gelatin are emerging as leading alternatives to traditional plastic packaging due to their enhanced capabilities and biodegradability. Blends of chitosan and gelatin combine chitosan’s antimicrobial and film-forming properties with gelatin’s biocompatibility and flexibility. These biomaterials possess tunable mechanical, biological, and physicochemical properties, making them suitable for biomedical, pharmaceutical, food packaging, environmental, and agricultural applications. This study investigates the preparation and characterization of composite biopolymer films based on chitosan and gelatin, incorporating coffee silverskin extract (SSE) as a natural bioactive additive. Coffee silverskin, a by-product of coffee roasting, is rich in phenolic compounds and demonstrates notable antioxidant potential. The objective of this work was to enhance the antioxidant, mechanical, and physicochemical properties of chitosan–gelatin films through the integration of SSE. The biocomposite materials were prepared using solvent casting, followed by extensive characterization techniques, including Fourier-transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, and UV–Vis spectroscopy. Additionally, color measurements, mechanical properties, and physicochemical properties were assessed. The transmission rates of oxygen and water vapor were also examined, along with the antioxidant activity of the films. The inclusion of coffee silverskin extract facilitated intermolecular interactions between the polymer chains, resulting in improved structural integrity. Furthermore, films containing CSE exhibited enhanced antioxidant activity (up to 28.43% DPPH radical scavenging activity), as well as improved water vapor barrier properties and mechanical strength compared to the pure chitosan–gelatin. The films showed a yellowish appearance. There was a noticeable reduction in the rate of oxygen transmission through the films as well. These results highlight the potential of coffee silverskin as a sustainable source of functional compounds for the development of bioactive materials suited for biodegradable packaging and biomedical applications. Full article

This study investigates the optimization of sol–silicate façade coatings modified with colloidal silica and a silane-based hydrophobizing additive to enhance hydrophobicity while maintaining a high water-vapor transmission rate (V). The effects of the binder ratio between potassium water glass (WG) and colloidal silica (CS), the type of colloidal silica (unmodified or epoxy-silanized), and the concentration of the hydrophobizing additive (HA) were systematically evaluated. Water-vapor transmission was determined according to EN ISO 7783, and surface wettability was measured before and after accelerated UV-A aging. Dynamic viscosity was monitored for two years to assess long-term storage stability. The optimized formulation contained 7 wt % potassium water glass, 15 wt % colloidal silica, and 1 wt % hydrophobizing additive. It exhibited stable viscosity over time (≈19,000 mPa·s after six months), high water-vapor transmission (V > 6700 g·m⁻²·d⁻¹, class V1), and an initial contact angle of 118°, which decreased only moderately after UV-A exposure. Coatings containing epoxy-silanized colloidal silica showed slightly lower transmission but still remained within the high V range suitable for vapor-open façade systems. The results confirm that balanced sol–silicate systems can combine durable hydrophobicity with long-term rheological and functional stability. Full article

This work presents the non-destructive assessment of polymeric composites based on synthetic matrices low-density polyethylene (LDPE) and polystyrene (PS) enhanced with chitosan (CS) biopolymer for use in active packaging systems for moisture control. Composites were prepared by incorporating CS at different contents (1, 3 and 5 phr) into LDPE and PS matrices. To evaluate the structural and thermal alterations induced by biopolymer loading, the materials were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The composites’ water-regulating properties—specifically, moisture absorption, retention, diffusion, and water vapor transmission rate—were quantitively tracked. Furthermore, the mechanical integrity of both dried and water-exposed systems was assessed via Shore D hardness testing. The results reveal a direct correlation between CS concentrations and enhanced hydrophilic behavior and water absorption, primarily attributed to the polar hydroxyl and amine groups within its molecular structure. The composites maintained adequate mechanical strength even after water exposure, confirming their structural stability for practical applications. This study demonstrates that the incorporation of CS into non-polar synthetic matrices significantly improves water affinity without requiring chemical compatibilizers, representing a cost-effective route to develop responsive packaging. The promise of these composites as responsive materials for real-time environmental interaction is highlighted by the successful non-destructive monitoring of their performance. This research establishes the feasibility and efficacy of non-destructive monitoring techniques in developing active packaging technologies, accelerating the progress of polymer-based systems with integrated and tunable moisture regulation capabilities. Full article

Perovskite solar cells (PSCs) have achieved rapid progress in recent years owing to their high-power conversion efficiency (PCE), low cost, and processability. However, poor device stability and carrier recombination remain significant obstacles to further development. Atomic layer deposition (ALD), with its atomic-level control over film thickness, excellent uniformity, and interfacial engineering capability, has attracted considerable attention in PSC research. This review summarizes the applications of ALD in PSCs, including low-temperature synthesis (typically below 350 °C), thickness and composition control (approximately 1 nm per 10 ALD cycles), defect passivation, encapsulation (water vapor transmission rates as low as 10⁻⁶ g·m⁻²·day⁻¹ under optimized conditions), and tandem devices. In addition, the mechanisms by which ALD enhances device efficiency and stability are discussed in depth, and the challenges and future prospects of this technique are analyzed. Full article

Diabetic ulcers are among the most common and challenging complications of diabetes mellitus, and effective therapeutic strategies remain elusive. While stem cell secretome (SCS)-based therapy has attracted considerable attention due to its regenerative potential, its direct application is hindered by low bioavailability and rapid diffusion at the wound site. To address these limitations, we designed a bilayer bacterial cellulose–gelatin (Bi-BCG) scaffold inspired by the hierarchical structure of native skin. This scaffold features a compact bacterial cellulose (BC) upper layer with nanoscale porosity and a porous BCG lower layer with pore sizes of ~52 μm, optimized for SCS delivery. The Bi-BCG scaffold demonstrated a water vapor transmission rate of 2384 g/(m²·24 h) and exhibited significantly improved SCS retention capacity while maintaining high fluid absorption, outperforming monolayer BCG scaffolds. Functionally, human umbilical cord-derived mesenchymal stem cell (hUCMSCs)-derived secretomes significantly enhanced the proliferation (by up to 70.7%) and migration of skin fibroblasts under high-glucose conditions, promoted vascular endothelial cell proliferation (increasing Ki-67+ cells from 25.87% to 46.89%) and angiogenic network formation, and effectively suppressed macrophage-mediated inflammatory responses and oxidative stress. In vivo, the combination of SCSs with the Bi-BCG scaffold exhibited a clear synergistic effect, achieving a wound closure rate of 78.8% by day 10 and promoting superior structural restoration with well-organized collagen deposition, outperforming either treatment alone. These findings underscore the potential of the Bi-BCG scaffold combined with SCSs as an effective strategy for enhancing diabetic wound healing. Full article

The design of hydrogel-based materials for wound care management requires the integration of multiple functionalities, including the capacity to maintain hydration, to prevent infection, and to adapt to the dynamic wound microenvironment. In this study, we fabricated innovative pH-reactive multilayer hydrogel patches based on ionically crosslinked alginate and incorporated with bioactive compounds, including Manuka honey, hyaluronic acid, and Ribes nigrum extract. The multilayer structure is coated with chitosan to improve water affinity and pH response. The patches are designed to respond to variable pH conditions typical of wound environments, with potential applicability to burn wounds. The hydrogel materials are characterized in terms of water content, swelling behavior, and water vapor transmission rate (WVTR). The chitosan-coated multilayer hydrogel exhibited high water uptake (swelling ratio up to 22.11 ± 0.25; water content 95.48 ± 0.05%) and controlled WVTR (~3450–3850 g/m²·day⁻¹), while degradation remained below 42% at pH 8 compared to >80% in single layers. Microstructural analysis is performed via optical microscopy to assess the morphology and uniformity of the multilayer system, while chemical characterization is conducted using Fourier-transform infrared (FTIR) spectroscopy. The results highlight the ability of the designed material to respond to pH variations and to accommodate bioactive agents within a structurally stable and hydrated network, suggesting its suitability for future investigations into controlled release applications. Full article

The development of organic light-emitting diodes (OLEDs) for high-resolution, large-area displays relies on effective encapsulation technology. Accordingly, this study proposes a novel multilayer structure utilizing a cyclo-olefin polymer-based film. This solution significantly reduces process time and cost while achieving remarkable barrier performance. Optimization involved presenting various models and enhancing substrate–film adhesion via ultraviolet or plasma treatment, consequently improving water vapor transmission rate. Furthermore, the optimized structure’s feasibility as an OLED encapsulation layer was confirmed. These results promise to enhance core technological capabilities, improving production yield and minimizing costs—key factors for next-generation displays. Full article

This study explores reusing discarded industrial polylactic acid (PLA), such as defective parts, scraps and burrs, for food contact applications. Reprocessing of PLA (PLA-RP) was simulated via melt extrusion, and the obtained pellets were characterized in terms of viscosity average molecular weight (M_v), melt flow index (MFI), the presence of non-intentionally added substances (NIASs) and the absence of metals to ensure that no substances exceeded the specific migration limits (SMLs). A slight reduction in the M_v, accompanied by an increase in the MFI, was observed in PLA-RP. In virgin PLA, fewer compounds were detected, likely related to residual additives. A higher variety and concentration of volatile and non-listed compounds were observed in reprocessed PLA (PLA-RP), with three exceeding their assigned Cramer class thresholds, requiring further evaluation. Most identified substances were typically linked to thermal degradation or potential additives for reprocessing. In both the virgin and reprocessed materials, all substances with SMLs remained below applicable thresholds, including trace metals. The PLA-RP was further processed into films by means of a compression moulding process. The structure, mechanical behaviour, thermal stability and water vapor transmission rate were comparable to those of virgin PLA, indicating no significant changes. The overall migration level tested in a fatty food simulant remained below regulatory limits. The materials fully disintegrated under laboratory-scale composting conditions in less than 3 weeks. Thus, reprocessed PLA shows great potential as a non-migrating material of interest in the sustainable food packaging field. Full article