Search Results (236)

The development of functional biomaterials based on natural polymers has gained increasing relevance due to the growing demand for sustainable and bioactive alternatives for biomedical and technological applications. In this study, chitosan was obtained from shrimp exoskeletons and used to formulate active films enriched with Mexican propolis, aiming to evaluate the influence of the extract on the physicochemical and functional properties of the resulting biomaterial. Propolis was incorporated into the chitosan film-forming solution at a final concentration of 1.0% (v/v). The propolis employed met the requirements of the Mexican Official Standard NOM-003-SAG/GAN-2017 regarding flavonoid content, total phenolic compounds, and antimicrobial activity; additionally, it was evaluated through antioxidant activity, hemolysis, and acute toxicity (LD₅₀) assays to provide a broader biological and safety assessment. The extracted chitosan exhibited a degree of deacetylation of 74% and characteristic FTIR spectral features comparable to those of commercial chitosan, confirming the quality of the obtained polymer. Chitosan–propolis films exhibited antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans, whereas pure chitosan films showed no inhibitory effect. Thermal analyses (TGA/DSC) revealed a slight reduction in thermal stability due to the incorporation of thermolabile polyphenolic compounds, along with increased thermal complexity of the system. SEM observations demonstrated reduced microbial adhesion and marked morphological damage in microorganisms exposed to the functionalized films. Overall, the incorporation of Mexican propolis enabled the development of a hybrid biomaterial with enhanced antimicrobial performance and potential application in wound dressings and bioactive coatings. Full article

Façades account for approximately 15–20% of a building’s embodied carbon, making them a key target for material decarbonization. While bio-composites are increasingly explored for façade insulation, cladding systems remain dominated by carbon-intensive materials such as aluminum and fiber-reinforced polymers (FRPs). This paper presents findings from a study investigating the use of food-waste-derived bulk fillers in bio-composite materials for façade cladding applications. Several food-waste streams, including hazelnut and pistachio shells, date seeds, avocado and mango pits, tea leaves, and brewing waste, were processed into fine powders (<0.125 μm) and combined with a furan-based biobased thermoset resin to produce flat composite sheets. The samples were evaluated through mechanical testing (flexural strength, stiffness, and impact resistance), water absorption, freeze–thaw durability, and optical microscopy to assess microstructural characteristics before and after testing. The results reveal substantial performance differences between waste streams. In particular, hazelnut and pistachio shell fillers produced bio-composites suitable for façade cladding, achieving flexural strengths of 62.6 MPa and 53.6 MPa and impact strengths of 3.42 kJ/m² and 1.39 kJ/m², respectively. These findings demonstrate the potential of food-waste-based bio-composites as low-carbon façade cladding materials and highlight future opportunities for optimization of processing, supply chains, and material design. Full article

This paper presents the potential use of sunflower seed hulls (SSH) as a sustainable filler for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biocomposites. Ground SSH were incorporated into the PHBV matrix at loadings of 15, 30, and 45 wt% via extrusion and injection molding. The Fourier Transform Infrared Spectroscopy (FTIR) analysis indicated the presence of possible interactions between the filler and the matrix. Mechanical testing revealed a significant increase in stiffness, with the tensile modulus increasing from 2.6 GPa for pure PHBV to approximately 4.5 GPa for the composite containing 45 wt% SSH. However, the tensile strength decreased by approximately 10–40%, while elongation at break dropped to 1.0–1.5%, depending on the SSH dosage, respectively. The thermal analysis indicated that high filler contents suppress crystallization during cooling under laboratory conditions in Differential Scanning Calorimetry (DSC) analysis due to the confinement effect. The key practical advantage is the exceptional improvement in dimensional stability with a processing shrinkage reduction of approximately 80% in the thickness direction. Although water absorption increased with filler loading, biocomposites containing 15–30 wt% SSH exhibited the optimal balance of high stiffness, hardness, and dimensional accuracy. These properties make the developed material a promising option for the production of precise technical molded parts. Full article

The growing interest in sustainable additive manufacturing has driven research into customized biocomposite filaments reinforced with natural fibers. This study evaluates the influence of flax fiber content (5–15 wt%) on the thermal, rheological, morphological, and mechanical properties of fully bio-based polyamide PA10.10 filaments intended for fused deposition modeling (FDM). Filaments containing up to 15 wt% flax fibers were produced using both conventional single-screw extrusion and the METEOR^® elongational mixer to compare shear- and elongation-dominated dispersive mechanisms. Increasing flax loading enhanced stiffness (up to +84% tensile modulus at 15 wt%) but also significantly increased porosity, particularly in METEOR-processed materials, leading to reduced strength and intrinsic viscosity. Microscopy confirmed fiber shortening during compounding and revealed porosity arising from moisture release and insufficient fiber wetting. Rheological analysis showed the onset of a pseudo-percolated fiber network from 10 wt%, while excessive porosity at higher loadings impeded melt flow and printability. Based on the combined evaluation of the mechanical performance, dimensional stability, and processability, a 5 wt% flax formulation was identified as the optimal compromise for FDM. A functional automotive demonstrator (Fiat 500 dashboard fascia) was successfully printed using optimized FDM parameters (nozzle 240 °C, bed 75 °C, speed 20 mm s⁻¹, 0.6 mm nozzle, 0.20 mm layer height, and 100% infill). The part exhibited controlled shrinkage and limited warpage (maximum 1.8 mm across a 165 × 180 × 45 mm geometry with a 3 mm wall thickness). Dimensional accuracy remained within ±0.7 mm relative to the CAD geometry. These results confirm the suitability of PA10.10/flax biocomposites for sustainable, lightweight automotive components and provide key structure–processing–property relationships supporting the development of next-generation bio-based FDM feedstocks. Full article

Biodegradable polymeric composites reinforced with natural fillers represent one of the most promising routes toward low-impact, circular, and resource-efficient materials. In recent years, a growing number of studies have focused on the valorization of plant- and animal-derived organic waste, ranging from agricultural residues and natural fibers to marine and livestock by-products. This review provides a comprehensive and comparative overview of these systems, analyzing the nature and origin of the waste-derived fillers, their pretreatments, processing strategies, and the resulting effects on mechanical, thermal, functional, and biodegradation properties. Particular attention is dedicated to the role of filler composition, morphology, and surface chemistry in governing interfacial adhesion and end-use performance across different polymeric matrices, including PLA, PCL, PBS, PHA, PHB, PBAT, and commercial blends such as Mater-Bi^®. The emerging applications of these biocomposites, such as packaging, additive manufacturing, agriculture, biomedical uses, and environmental remediation, are critically discussed. Overall, this work provides fundamental insights to support the development of the next generation of biodegradable materials, enabling the sustainable valorization of organic waste within a circular-economy perspective. Full article

Biocomposites based on natural fibres represent a promising solution for the circular economy. The aim of this study was to develop and characterise a biodegradable composite based on sheep wool from herds raised in the Kyrgyz Republic and polylactide (PLA 4032D). Composite samples with a wool–PLA ratio of 50:50 were fabricated by thermoforming at a temperature of 168 °C for 30 s (n = 10). Mechanical properties tests were performed (PN-EN ISO 604—compression tests), for impact resistance (Charpy method), differential scanning calorimetry (DSC), and measurements of density and thermal conductivity. Biodegradation samples were subjected to enriched soil conditions for 6 weeks in two variants (with and without irrigation). The results showed that the addition of sheep wool to the PLA matrix significantly increased compressive strength (23.56 ± 5.23 MPa) and impact energy absorption (226.2 ± 23.8 kJ/m²) compared to neat PLA. After biodegradation, a 59% reduction in compressive strength was observed while maintaining an increase in fracture energy, suggesting a change in the failure mechanism. The density (0.27 ± 0.02 g/cm³) and the thermal conductivity (0.127 W/m·K) comparable to polymer foams indicate potential for thermal insulation applications. Microscopy and DSC analysis confirmed complete biodegradation under soil conditions. The developed biocomposite from Kyrgyz sheep wool demonstrates the potential for valorisation of local fibrous waste for biodegradable materials with functional insulation properties. Full article

Natural resources, such as wood components (cellulose, hemicellulose, and lignin) and plant oils, have drawn significant interest for the development of polymeric biocomposites. Despite some advantages of soybean hull (SH) and soybean meal (SM), such as high abundance, low cost, and high functionality, both materials lack film-forming properties and mechanical performance and are highly hydrophilic, which makes them incompatible with most polymer matrices. This study demonstrates the suitability of using various ratios of SH and SM in combination with other soy-based derivatives—soy oil-derived polymers—simultaneously in the development of cross-linked biocomposites. For this purpose, we reacted SH or SM with maleic anhydride (via hydroxyl groups) to introduce reactive sites for free-radical polymerization, followed by the bulk polymerization of the maleinized SH and SM in the presence of high-oleic soybean oil-based acrylic monomer (HOSBM). As a result, simultaneous “grafting from” polymerization on the filler surface and formation of the HOSBM homopolymer occur. The synthetic procedure results in a homogeneous distribution of fillers, both modified with soy-derived polymeric chains in the biocomposite matrix (polyHOSBM). In the study, up to 35 wt.% of total SH and SM was incorporated into the biocomposites, further cross-linked via post-polymerization autoxidation of polyHOSBM unsaturated functionalities. The mechanical characterization shows that incorporating 25 wt.% soybean hull leads to an enhanced Young’s modulus and tensile strength in comparison to other investigated biocomposites. Overall, the resulting cross-linked biocomposite films exhibit Young’s modulus in a range of 50–140 MPa, tensile strength of 1–2.9 MPa, and elongation at break of 18–55%. This work demonstrates the potential of the developed synthetic procedure to homogeneously distribute two abundant natural fillers simultaneously in cross-linked biocomposites. Full article

Citrus fruits are among the most important global crops, with annual production exceeding 160 million tons. Processing produces significant waste, mainly peels, seeds, and pulp, which can make up to fifty percent of the fruit’s mass. This review critically examines innovative ways to valorize these byproducts. Recent research shows that peels, seeds, and pulp can be converted into high-value materials, including biocomposites and biomaterials, marking a shift from traditional uses like animal feed and biogas production. Notable innovations include smart packaging, pectin-based wound dressings, and biodegradable polymers for sustainable electronics. Advanced green extraction methods, such as deep eutectic solvents, have achieved extraction yields over 85% for flavonoids. Additionally, multifunctional biorefineries processing citrus and olive residues have increased biogas yields by 38–42%. The review explores emerging applications in nanotechnology, nutraceuticals, biodegradable polymers, and functional coatings, all aligned with principles of circular economy and green chemistry. These advances suggest that citrus waste can play a significant role in sustainability efforts and new market development. The review also discusses barriers to adoption, including scalability challenges, regulatory limits, and consumer acceptance, from both global and regional viewpoints. Full article

A promising strategy for pancreatic cancer therapy involves developing nanocarriers capable of simultaneously delivering various antitumor substances with diverse physicochemical properties, often resulting in synergistic effects. In the present work, novel biocomposites were developed using amphiphilic N-vinylpyrrolidone polymer incorporating bortezomib (BTZ) and modified with either the DR5-selective TRAIL cytokine (DR5-B) or its fusion with the iRGD effector peptide (DR5-B-iRGD), resulting in AmphPVP-BTZ-DR5-B and AmphPVP-BTZ-DR5-B-iRGD formulations. The release of BTZ was most extensive at acidic pH 5.6, mimicking endolysosomal compartments, while at near-neutral pH 7.4 and alkaline pH 8.2 the release was slower and less complete, indicating a smart pH-responsive behavior suitable for triggered release in the tumor microenvironment. Both AmphPVP-BTZ-DR5-B and AmphPVP-BTZ-DR5-B-iRGD significantly inhibited the growth of pancreatic adenocarcinoma cell lines PANC-1, BxPC-3, and MIA PaCa-2 and induced more rapid internalization of the DR5 receptor in MIA PaCa-2 cells than unmodified particles and free DR5-B or DR5-B-iRGD. Importantly, AmphPVP-BTZ-DR5-B-iRGD exhibited a more pronounced DR5 internalization rate and cytotoxic effect than AmphPVP-BTZ-DR5-B owing to the presence of fusion protein with internalizing iRGD peptide. Both biocomposites induced cell death via the apoptotic pathway while exhibiting minimal cytotoxic effects on healthy cells. Therefore, biocomposites incorporating BTZ and functionalized with DR5-selective TRAIL variants DR5-B or DR5-B-iRGD represent a promising avenue for future studies in pancreatic cancer animal models. 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

Polybutylene adipate terephthalate (PBAT), a flexible biodegradable polyester, has gained widespread use in packaging applications due to its ability to degrade under controlled conditions, producing non-toxic substances. While this property makes PBAT particularly attractive for the development of transient electronic devices, this potential application remains unexplored. To address this research gap, we developed PBAT-based composites and modified their electrical properties through CO₂ laser functionalization. Although laser treatment of neat PBAT primarily resulted in material ablation, the incorporation of lignin and silica-based fillers enabled the formation of electrically conductive pathways. Among the various fillers tested, dealkaline lignin (DEALK) and glass fibers (GFs) provided the optimal combination of electrical conductivity, mechanical properties, and processability. Characterization techniques (electrical measurements, optical microscopy, SEM, EDX, and TGA) highlighted that by optimizing laser treatment and the filler concentration, it is possible to produce conductive tracks with remarkably low sheet resistance. Hybrid composites containing 10–15 wt% of GF and 20–25 wt% of lignin demonstrated the best electrical performance with values as low as 3.5 Ω/sq, which were further reduced to 1.72 Ω/sq after laser process optimization. These findings establish PBAT composites as promising candidates for sustainable transient electronics. Full article

Agricultural and agro-industrial waste, produced in vast quantities worldwide, presents both environmental and economic challenges. Microbial valorization offers a sustainable solution, with bacterial cellulose (BC) emerging as a high-value product due to its purity, strength, biocompatibility, and biodegradability. This review highlights recent advances in producing BC from agricultural and agro-industrial residues via optimized fermentation processes, including static and agitated cultivation, co-cultivation, stepwise nutrient feeding, and genetic engineering. Diverse wastes such as fruit peels, sugarcane bagasse, cereal straws, and corn stover serve as cost-effective carbon sources, reducing production costs and aligning with circular bioeconomy principles. Advances in strain engineering, synthetic biology, and omics-guided optimization have significantly improved BC yield and functionalization, enabling applications in food packaging, biomedicine, cosmetics, and advanced biocomposites. Process innovations, including tailored pretreatments, adaptive evolution, and specialized bioreactor designs, further enhance scalability and product quality. The integration of BC production into circular bioeconomy models not only diverts biomass from landfills but also replaces petroleum-based materials, contributing to environmental protection and resource efficiency. This review underscores BC’s potential as a sustainable biomaterial and identifies research directions for overcoming current bottlenecks in industrial-scale implementation. Full article

This study explores the valorization of chestnut burrs (Castanea sativa), an abundant agro-industrial residue, as a natural filler for polylactic acid (PLA)-based biocomposites with potential applications in additive manufacturing. PLA/chestnut burr composite filaments were prepared by melt extrusion with filler contents of 2.5%, 5%, 10%, and 15% w/w, and their chemical, thermal, morphological, and mechanical properties were systematically characterized. ATR-FTIR confirmed the absence of major chemical modifications of the PLA matrix. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), the latter performed on both the extruded filaments and the material after fused deposition modeling (FDM) 3D printing, revealed a slight decrease in thermal stability with increasing filler content, coupled with enhanced crystallinity. Mechanical properties analysis showed that the addition of chestnut burrs did not negatively impact the viscoelastic behavior of the filaments. Scanning electron microscopy (SEM) highlighted good filler dispersion up to 5% loading, while higher percentages led to increased surface roughness and microvoids. Importantly, antioxidant activity assays (DPPH, ABTS, FRAP, and Folin–Ciocâlteu) demonstrated that the incorporation of chestnut burr significantly enhanced the radical-scavenging capacity, reducing power, and total phenolic content (TPC) of PLA. These functionalities were preserved, and in some cases amplified, after FDM 3D printing, indicating that the processing conditions did not degrade the bioactive constituents. Overall, chestnut burrs are confirmed as an effective multifunctional filler for PLA, improving its antioxidant activity while maintaining structural and thermal performance, supporting the development of sustainable biocomposites for emerging applications. Full article

Despite promising results, biocomposite research still requires elaboration, particularly with regard to functional properties and applications. In this study, multilayer biocomposites based on gelatin, κ-carrageenan and carboxymethylcellulose were enriched with sage or blackberry extracts. The films were characterized based on their physicochemical traits and bioactivity for application as active packaging and environmental biodegradation. FTIR confirmed extract integration and strong matrix interactions, while UV-VIS analysis showed efficient UV blocking. Water properties remained acceptable (WVTR ≈ 550 g/m² × d); solubility decreased for BB (41.73% vs. 53.45% control). Mechanical testing indicated a plasticizing effect: elongation increased (20.00% control; 35.35% BB; 39.29% SAGE), while tensile strength and Young’s modulus decreased. Antioxidant capacity rose (FRAP: 0.38 control, 1.97 BB, 4.48 SAGE µTrolox/mg; DPPH: 6.38% control, 85.68% BB, 78.25% SAGE; MCA: none). During refrigerated storage, antimicrobial effects were most evident on days 6–9. Lipid oxidation peaked for BB (0.92 mg MDA/kg, day 9), while pH was more stable with SAGE. Biodegradation and phytotoxicity confirmed environmental safety and compostability, with increased humic acid carbon in vermicompost. Overall, the results confirm the relevance of modifying biopolymers using green chemistry and highlight their importance for quality management, food safety and sustainable circular economy strategies. Full article

Exhibiting significant potential for sustainable packaging due to their renewability and biodegradability, soy protein isolate (SPI) films are nevertheless critically hampered by inherent brittleness, poor water resistance, and a lack of bioactivity. Herein, we demonstrate a hierarchical multi-network strategy that transforms SPI into a high-performance, functional biocomposite. A robust covalent backbone was forged via Schiff base cross-linking between SPI and dialdehyde cellulose nanocrystals (DACNCs) derived from agricultural biomass, while proanthocyanidins (PAs) were strategically incorporated to create a secondary, pervasive hydrogen-bonding network. This hierarchical architecture effectively overcomes the typical trade-offs between mechanical strength and functionality seen in singly modified biopolymers, unlocking a suite of remarkable performance enhancements. The optimized film exhibited a 491% increase in tensile strength (to 15.54 MPa) and elevated thermal stability to 330 °C. Critically, the film was endowed with potent functionalities, including complete UV-blocking, high antioxidant capacity (93.2% ABTS scavenging), and strong, broad-spectrum antimicrobial activity. The film’s practical efficacy was validated in a preservation test, where the coating extended blueberry shelf life by inhibiting fungal spoilage and reducing weight loss by nearly 30% relative to uncoated controls after 15 days of storage. This work provides a powerful framework for developing advanced biocomposites with tailored properties for active food packaging and beyond. Full article