Search Results (1,574)

This study investigates the effect of phase change materials (PCM) on the properties of modified potato starch binders and hemp shive-based bio-composites, emphasizing their potential for sustainable construction applications. PCM-modified binders have shown reduced viscosity during gelatinization, enhancing their workability and uniformity during processing. A microstructural analysis reveals that PCM addition results in a denser and more cohesive binder network, leading to improved adhesion and reduced porosity. A thermal analysis demonstrates a shift to higher decomposition temperatures and a linear increase in specific heat capacity within the PCM phase-change range (20–30 °C), significantly enhancing the thermal storage capacity of the bio-composites. PCM addition improves compressive strength by up to twice, with optimal performance achieved at 8% PCM additive content. The prolonged cooling time, up to three times longer in bio-composites with PCM additive, highlights their effectiveness in thermal regulation. Additionally, bio-composites with a PCM additive exhibits increased bulk density and reduced water swelling, improving dimensional stability. These findings underline the dual benefits of enhanced thermal and mechanical performance in bio-composites with a PCM additive, making them a viable alternative to conventional building materials. Full article

This work investigates the influence of crystallinity on the mechanical properties of needle-punched non-woven flax/polylactic acid (PLA) biocomposites with different flax fiber contents. Biocomposites were fabricated by a compression molding adopting different cooling rates to understand the mechanism of crystallinity and their contribution to the mechanical properties. Image-based analysis of the fiber distribution in non-woven preform indicates the probable origins of the residual porosities and the potential nucleation sites for crystal formation within the composites. The improvement of 25% and 100% in flexural modulus is observed for the composites with 40% and 50% of flax fiber mass fractions, respectively, when subjected to a lower cooling rate, which implies the significant influence of the void content on the brittleness of composites. The impact properties of the composites decrease from 11% to 18% according to the flax fiber mass fraction when the cooling rate decreases to 1 °C/min, and the composites become more brittle. The induced impact and flexural properties of the composites are compared with those of other composites in the literature to emphasize their applicability to semi-structural applications. Full article

To increase the use of agricultural residues, such as date palm fibers, for the sustainable reinforcement of biocomposites, this study investigated the incorporation of varying weight percentages of date palm microfibers (DPMF) ranging from 0 wt.% to 10 wt.% into polycaprolactone (PCL) matrix. Biocomposites were fabricated using a combination of compression molding and dry blending techniques with and without sodium hydroxide (NaOH) alkali treatment. The surface modification was found to increase the surface roughness of the fibers, removing impurities such as lignin, hemicellulose, and wax, while improving crystallinity, as evidenced by FTIR, XRD, TGA, and particle size analyses. Among the different biocomposites investigated, the results for 5 wt.% DPMF content biocomposites exhibited the highest tensile properties: approximately 20% increase in tensile strength and 164% increase in Young’s Modulus in comparison to neat PCL. The crystallinity of the matrix exhibited an increasing trend from approximately 39% for neat PCL to 43% for the 5 wt.% DPMF biocomposites. Furthermore, treated biocomposites demonstrated higher water-repellency behavior and improved thermal properties. Dynamic mechanical analysis (DMA) results indicated enhanced storage moduli for alkali-treated composites; at 35 °C, the storage modulus showed approximately 22% increase compared to the untreated DPMF biocomposites, reflecting improved stiffness and thermomechanical performances. This study highlights the potential of DPMF as an efficient, eco-friendly alternative to fossil-based conventional reinforcement for biocomposite materials’ potential for sustainable rigid packaging applications. Full article

Biocomposite materials respond to market trends and regulatory pressures for environmentally friendly packaging. Few studies have assessed the social life cycle assessment (SLCA) using stakeholder indicators across the entire supply chain. The objective of this study is to provide reliable indicators and data to compare the SLCA of jar lid biocomposites filled with post-harvest banana fibers (BFs) in Colombia. Methodologies from the United Nations Environment Programme, the relevant literature, and Colombian regulations were used to select indicators. A comprehensive survey involved all stakeholders in the supply chain and consumer responsibility during the use phase. The data collected were integrated, scored, and weighted. This approach aimed to reduce uncertainty in comparing different scenarios and contribute to the standardization and integration of SLCA methods. The study highlights the significant benefits of incorporating banana fibers (BFs) into jar lids. Lids composed of 40% BFs provide notable social advantages, particularly within the agricultural sector. They contribute to improving the economic income and quality of life for farmers, transporters, and intermediaries while promoting equity among them. Additionally, these lids help preserve cultural heritage in local communities. From a corporate perspective, beyond financial gains, companies enhance their sustainability visibility by offering a product that is environmentally friendly, naturally sourced, and directly connected to farmers. Furthermore, these lids strengthen the overall social impact of the supply chain and business sector by utilizing renewable and locally available resources. Full article

Composite materials are gaining attention owing to their exemplary characteristics and, if the materials are eco-friendly, they attract much more. One such composite of poly lactic acid (PLA) combined with bamboo fiber in the ratio of 80:20 is selected for this study. The composites are manufactured using additive manufacturing, or the 3D-printing technique. In this article, a novel approach of infilling a honeycomb with around 12 infill patterns has been made, and all the 3D-printed specimens were tested for their mechanical and tribological properties. The 3D-printed composites were characterized using Fourier Transform InfraRed spectroscopy (FTIR) and X-Ray Diffraction (XRD) to evaluate their chemical composition and crystallite size (CS), respectively. Based on the results, the cross infill pattern outperforms irregular geometries like the Gyroid in terms of impact strength owing to its efficient stress distribution and superior interlayer bonding. By utilizing bidirectional reinforcement and distributing loads uniformly, the grid infill was able to attain the Shore D maximum hardness due to its strong 3D lattice structure; the Octet infill is very resistant to wear, which improves energy absorption and decreases material loss. Such honeycomb-filled 3D-printed composites can act as high-mechanical-strength components and find their applications in aerospace applications like drones and their allied structures. Full article

This review explores the potential of water hyacinth (WH) as a sustainable material in cement-based applications, focusing on its use as an addition, admixture, and fiber reinforcement. WH’s unique physical and chemical properties, such as high cellulose content and pozzolanic potential, make it suitable for bio-composites and eco-friendly concrete formulations. The present study highlights several promising findings, including the enhancement of the resulting mechanical properties and the reduction in their environmental impact when the WH is incorporated in controlled quantities. Challenges such as workability and durability issues at higher dosages are discussed. This review aims to bridge knowledge gaps and support WH’s adoption in sustainable construction practices. Full article

This study focuses on the development of an insulation biocomposite using Doum palm (Chamaerops humilis) fibers reinforced with a natural binder based on citric acid and glycerol. The main objective is to optimize the thermal conductivity and mechanical properties of the biocomposite as a function of fiber preparation (short or powdered fibers) and binder content (20%, 30% and 40%), and relate them to the bonding of the fibers and the binder. The obtained results suggest that the addition of the binder greatly enhances the density, compressive strength and Young’s modulus of biocomposites. More specifically, the addition of 20% by weight of the citric acid/glycerol binder improves the bond between fibers, whether they are short fibers or powders. This leads to an increase in the mechanical properties, with Young’s modulus reaching (212.1) MPa and compressive strength at (24.3) MPa. On the other hand, the results show that these biocomposites also have acceptable thermal insulation performance, achieving a thermal conductivity of (0.102) W/(m·K), making them suitable for a variety of applications in sustainable buildings and for refurbishment. Full article

Viral infections remain a major concern, as existing treatments often yield inadequate responses or lead to the development of antiviral resistance in some cases. Fucoidan extracted from Undaria pinnatifida (F) is a natural sulphated polysaccharide that exhibits antiviral action. Despite its potential, the biomedical application of F is limited due to its difficult administration through trans-mucosal, skin, or oral ingestion. The most effective way to solve these problems is to propose novel methods of administration aiming to ensure better contact between the biopolymers and pathogens, leading to their inactivation. In this work, the synthesis of films based on chitosan (Ch)-coupled F is reported, aiming to generate a synergic effect between both biopolymers in terms of their antiviral and antioxidant capability. Biocomposites were prepared by a sonochemical method. They were characterized to infer structural properties, functionality, and possible F-Ch interactions by using Zeta potential, FTIR, and XRD techniques. The biocomposites showed excellent film-forming ability. They also exhibited improved antioxidant activity with respect to F and Ch individually and proved to be non-cytotoxic. These results demonstrate, for the first time, the antiviral activity of F:Ch biocomposites against bovine coronavirus and human viruses (adenovirus, poliovirus, herpes simplex, and respiratory syncytial virus), which could be applied in film form to prevent or treat viral infections. Full article

The growing need to mitigate the environmental impact of human activities has underscored the importance of biomaterials in sustainable architecture and construction. In this systematic review, advancements in bio-composite materials are consolidated and critically evaluated, emphasizing their thermal insulation properties and broader applications in sustainable building practices. Key aspects analyzed included morphology, internal structure, and thermal performance, along with supplementary insights into mechanical properties when available. The review focused on studies published between January and October 2024, sourced from the Scopus database and adhering to PRISMA guidelines. A keyword meta-analysis using VOSviewer (version 1.6.20) illustrated keyword co-occurrence trends. Methods for assessing bias included evaluating study design, data collection processes, and potential conflicts of interest, aligned with PRISMA standards. Significant findings revealed bio-composites achieving thermal conductivity values as low as 0.016 W/m·K, surpassing many traditional materials in insulation performance. Data from 48 studies, analysing 50 bio-composite materials, showed that 44% were optimized for thermal insulation and 40% for sub-structural applications. These materials also exhibit biodegradability and recyclability, critical attributes for sustainable construction. However, challenges such as scalability and durability remain as the key barriers to widespread adoption. In this review, the viability of bio-composites as sustainable alternatives to traditional materials is highlighted and research priorities are identified, particularly in scaling production technologies and enhancing durability testing methods, to advance their application in sustainable building practices. Full article

This paper presents the preparation and study of the properties of alginate materials, which were obtained on the basis of sodium alginate, activated carbon, cellulose, and calcium chloride. Alginate–carbon (AlgCa + C) and alginate–cellulose (AlgCa + Cel) composites, as well as pure calcium alginate (AlgCa) for comparative purposes, were obtained. Their textural (nitrogen adsorption/desorption isotherms), morphological (scanning electron microscopy), thermal (thermal analysis), and acid–base (pH drift method) properties, as well as the swelling index, were investigated. Additionally, to determine the adsorption properties, comprehensive equilibrium and kinetic studies of the adsorption of sodium salts of ibuprofen (IBP), diclofenac (D), and naproxen (NPX) from aqueous solutions on biocomposities were carried out. Adsorption isotherms were fitted using the Marczewski–Jaroniec isotherm equation (R² = 0.941–0.988). Data on the adsorption rate were analyzed using simple kinetic equations, of which the best quality of fit was obtained using the multi-exponential equation (R² − 1 = (3.9 × 10⁻⁴)–(6.9 × 10⁻⁴)). The highest obtained adsorption values were reached in systems with alginate–carbon composite and were 1.23 mmol/g for NPX, 0.81 mmol/g for D, and 0.43 mmol/g for IBP. The AlgCa + C material was characterized by a large specific surface area (1151 m²/g), a high degree of swelling (300%) and high resistance to high temperatures. Full article

This study focused on examining the reinforcement of milkweed fibers in polylactic acid (PLA) bio-composites used for dashboards in car interiors. Milkweed fiber is a natural fiber with a hollow structure that provides tremendous thermal insulation and noise resistance properties. Firstly, the milkweed fibers were blended with PLA fibers in a weight ratio of 75:25 using an air-laying process. Then, several layers of nonwoven material were compressed in a hydraulic press to obtain bio-composites. Finally, three bio-composites were obtained with different numbers of layers. The density, microstructure, thermal conductivity, sound transmission loss (STL), mechanical properties, dynamic mechanical analysis (DMA), and contact angles of the bio-composites were evaluated. The microstructure analysis revealed that some milkweed fibers collapsed due to the high-pressure molding process, which does not affect the bio-composite properties. The bio-composite with a higher number of nonwoven layers presented a poor interface between PLA and milkweed fibers, thus making it less homogeneous. This bio-composite showed a decrease of 5% in thermal conductivity values and a 19% increase in STL values. In addition, it exhibited a 160% increase in specific flexural strength and a 335% increase in specific flexural modulus compared to samples with a lower number of nonwoven layers. Therefore, it offers the best mechanical-property-to-density ratio, with values that conform to the specifications required for automotive dashboards. Full article

Zinc oxide (ZnO) particles were successfully synthesized through the green method using aloe vera extract and zinc nitrate (1:1). The structure, morphology and properties of the biosynthesized ZnO (bioZnO) particles were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), time of flight secondary ion mass spectrometry (TOF-SIMS) and thermogravimetry (TG). The morphology and the size of ZnO particles were elucidated by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS). Then, the ability of bioZnO to activate sulfur curing of natural rubber (NR) was tested and compared to commercial ZnO traditionally used as vulcanization activator. The bioZnO showed similar activity in the vulcanization process to commercial ZnO. NR composites containing bioZnO were pro-ecological in nature and exhibited better mechanical characteristics and durability against thermo-oxidative aging than NR with commonly used micrometric ZnO. Moreover, NR vulcanizates containing bioZnO showed good mechanical properties in dynamic conditions and satisfactory thermal stability. The present research is new and in addition to the analysis of biosynthesized ZnO particles, the effect of the activator in the vulcanization process of the NR elastomer and its influence on the properties of the final products were additionally discussed. Full article

The concept and feasibility of producing liposomes by rehydrating engineered lipid nanoconstructs are demonstrated in this study. Nanoconstructs of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) were produced using a microfluidic delivery probe integrated with an atomic force microscope. The subsequent rehydration of these POPC constructs led to the formation of liposomes, most of which remained adhered to the surface. The size (e.g., diameter) of the liposomes could be tuned by varying the lateral dimension of the lipid constructs. Hierarchical liposomal structures, such as pentagons containing five liposomes at the corners, could also be designed and produced by depositing lipid constructs to designated locations on the surfaces, followed by rehydration. This new means allows for regulating liposomal sizes, distributions, and compositions. The outcomes benefit applications of liposomes as delivery vehicles, sensors, and building blocks in biomaterials design. The ability to produce hierarchical liposomal structures benefits numerous applications such as proto-cell development, multiplexed bio-composite materials, and the engineering of local bio-environments. Full article

The buildup of abandoned plastics in the environment and the need to optimize agricultural waste utilization have garnered scrutiny from environmental organizations and policymakers globally. This study presents an assessment of the thermal decomposition of date seeds (DS), polypropylene homopolymer (PP), and their composites (DS/PP) through experimental measurements, machine learning convolutional deep neural networks (CDNN), and kinetic and thermodynamic analyses. The experimental measurements involved the pyrolysis and co-pyrolysis of these materials in a nitrogen-filled thermogravimetric analyzer (TGA), investigating degradation temperatures between 25 and 600 °C with heating rates of 10, 20, and 40 °C.min⁻¹. These measurements revealed a two-stage process for the bio-composites and a decrease in the thermal stability of pure PP due to the moisture, hemicellulose, and cellulose content of the DS material. By utilizing machine learning CDNN, algorithms and frameworks were developed, providing responses that closely matched ($R^2~0.942$) the experimental data. After various modelling modifications, adjustments, and regularization techniques, a framework comprising four hidden neurons was determined to be most effective. Furthermore, the analysis revealed that temperature was the most influential parameter affecting the thermal decomposition process. Kinetic and thermodynamic analyses were performed using the Coats–Redfern and general Arrhenius model-fitting methods, as well as the Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose model-free approaches. The first-order reaction mechanism was identified as the most appropriate compared to the second and third order F-Series solid-state reaction mechanisms. The overall activation energy values were estimated at 51.471, 51.221, 156.080, and 153.767 kJ·mol⁻¹ for the respective kinetic models. Additionally, the kinetic compensation effect showed an exponential increase in the pre-exponential factor with increasing activation energy values, and the estimated thermodynamic parameters indicated that the process is endothermic, non-spontaneous, and less disordered. Full article

Agriculture faces numerous challenges: infectious diseases through phytopathogens and soil nutrient deficiencies hinder plant growth, reducing crop yields. Biopolymer nanocomposites offer promising solutions to these challenges. In this work, we synthesize and characterize novel bionanocomposites (ι-CG-Mn) of manganese (hydr)oxide nanoparticles (approx. 3 to 11 nm) embedded in the matrix of the natural polysaccharide ι-carrageenan (ι-CG). Using spectroscopic methods we verify the presence of the nanoparticles in the polymer matrix while leaving the polysaccharide structural characteristics unaffected. Elemental analysis determines the mass content of metal ions in the ι-CG-Mn to be approx. 1 wt%. Electron microscopy techniques show the supramolecular organization of the ι-CG-Mn and the homogeneous nanoparticle distribution in the polymer matrix, while thermal analysis reveals that the bionanocomposite maintains high thermal stability. Moreover, the co-incubation of the phytopathogen Clavibacter sepedonicus with ι-CG-Mn inhibits the pathogen growth by 67% compared to the control. Our bionanocomposites demonstrate (1) strong bactericidal activity and (2) potential as microfertilizers that stimulate agricultural plant growth through the dosage of metal ions. These properties arise from the bioactivity of the widely available, naturally sulfated polysaccharide biopolymer matrix, combined with the antimicrobial effects of manganese (hydr)oxide nanoparticles, which together enhance the efficacy of the biocomposite. The non-toxic, biocompatible, and biodegradable nature of this biopolymer satisfies the high environmental demands for future biotechnological and agricultural technologies. Full article