Search Results (1,101)

Additive manufacturing (AM), often referred to as 3D printing, has seen significant advances over the last few years. Through extensive research covering a wide range of industries from automotive and aerospace to healthcare, AM comes with the advantage of reduced manufacturing costs and ease of transition from design to real prototype. This review paper navigates the landscape of the AM process to highlight the latest findings in terms of process, materials, and applications by analyzing publications between 2022 and 2025. A particular focus is given to the integration of new materials including high-performance polymers and bio-based composites, types of printing materials that can enhance the performance and durability of 3D printing processes. In addition, the paper examines advances in printing technologies, including multi-material and large-format printing, as well as the integration of artificial intelligence for process optimization and quality control. Considering these advances, critical challenges such as the productivity, high cost, limited material options, and ethical concerns over intellectual property are also addressed. By synthesizing current trends and assessing future directions, while considering a critical view, this study aims to inform researchers and industry stockholders about the evolving additive manufacturing landscape and the opportunities and obstacles on the horizon. Full article

The development of advanced wound dressing materials with enhanced antibacterial properties is critical for improving patient outcomes and reducing infection risks. This study introduces a novel bio-based aerogel composed of copper-crosslinked alginate and hyaluronic acid, synthesized using supercritical gel drying techniques. Alginate and hyaluronic acid polymers are widely used in the pharmaceutical and medical industries because of their nontoxicity, biodegradability, and biocompatibility. This study aimed to create an aerogel that could be used as a potential wound dressing material by crosslinking hyaluronic acid and alginate with copper. The bio-based aerogel was prepared by ionic gelation and supercritical gel drying. The prepared materials were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), BET surface area analysis, and energy-dispersive X-ray fluorescence (XRF). Moreover, the aerogel wound dressing properties were evaluated in terms of fluid uptake and antibacterial activity against S. aureus and E. coli. The physicochemical characterization of the prepared aerogels revealed their unique structural and morphological features, which are influenced by copper ion concentration and crosslinking time. Regarding their wound dressing evaluation, both aerogel and hydrogel were found to have antibacterial properties when tested on S. aureus with inhibition zones of (36 mm, 23 mm) and E. coli (31.6 mm, 21 mm) for hydrogel and aerogel, respectively. Also, excellent fluid uptake was found to reach up to 743%. These findings underscore the potential of copper-crosslinked alginate–hyaluronic acid aerogels as innovative wound dressing materials that combine superior antibacterial efficacy with excellent fluid management, paving the way for improved wound healing solutions. Full article

The extraction of cellulose from underutilized forest residues can diversify bio-based material supply chains and reduce pressure on commercial pulps. In this study, cellulose was isolated from Tibouchina lepidota (Bonpl.) Baill pruning residues through an alkaline–acid–oxidative protocol, and its suitability for polymeric applications was evaluated. Two granulometric fractions (250 µm and 125 µm) were used; the yields were 4.73 ± 0.12 g and 3.62 ± 0.11 g per 50 g of biomass, equivalent to 90.5% and 92.8% recovery, respectively (fractional remains as bleached pulp after removal of non-cellulosic components). Fourier Transform Infrared spectroscopy (FTIR) showed the disappearance of lignin and hemicelluloses bands and a pronounced β-glucopyranosic signal at 894 cm⁻¹, indicating high purity. Selective solubility in 17.5% NaOH classified the polymer as β-cellulose, suitable for wet spinning and film regeneration. Optical microscopy revealed smooth fibers of 25–50 µm length and 0.5–1 µm diameter, with aspect ratios ≥ 50, indicating favorable morphology for load transfer in composites. Statistical analysis (Shapiro–Wilk, F-test, and Student’s t-test) confirmed the significant influence of particle size on yield (p < 10⁻¹⁵). Overall, T. lepidota residues constitute a viable source of high-purity β-cellulose, whose molecular integrity and microstructure satisfy the requirements of sustainable polymeric manufacturing. Full article

This review paper explores the transformative potential of polymer composites and adhesives in reducing the weight of aircraft landing gear, thereby improving fuel efficiency and lowering emissions. The replacement of conventional metallic materials and mechanical fastenings with advanced thermoset/thermoplastic composites and adhesives can significantly enhance durability and performance in demanding operational environments. Unlike traditional fastening methods, the structural adhesives eliminate the weight penalties associated with mechanical fasteners, offering a lighter and more reliable solution that meets the rigorous demands of modern aerospace engineering. Furthermore, the review highlights a variety of manufacturing techniques and innovative materials, including bio-based polymers, self-healing materials, noobed composites, helicoid composites, and hybrid composites. The use of thermosets and vitrimers in adhesive bonding are presented, illustrating their ability to create robust and durable joints that enhance the structural integrity of landing gear systems. The paper also addresses current challenges, including recycling limitations and high material costs. Sustainability considerations, including the integration of self-healing materials, structural health monitoring systems, and circular economy principles, are discussed as essential for aligning the aerospace sector with global climate goals. Full article

Foams, as a type of porous materials, have found broad functional and structural application in heat and sound insulation, the mitigation of mechanical vibrations and impacts, packaging, etc. This paper aims to comprehensively review recently developed biobased foams (BBFs) with a comparison with their counterparts—namely, synthetic polymer foams—in terms of their foaming methods, physical and mechanical properties, and broad applications. A brief introduction to general foams, polymeric foams, and BBFs is provided, followed by a comparison of the related foaming methods; physical, mechanical, and chemical properties; and current and prospective applications. Several main polymer foaming methods (e.g., physical, chemical, and mechanical foaming) and their unique features are further examined in detail. The structure-related properties of polymeric foams (e.g., mass density, thermal conductivity, and rate effects in mechanical responses) are discussed, and the fundamental linearly viscoelastic models are summarized to account for the simple rate effect in the mechanical moduli of polymeric foams under varying loading rates. Furthermore, specific focus is placed on the foaming processes and material properties of sustainable BBFs (e.g., soybean-based, corn-based, and starch-based foams) and their potential to substitute conventional synthetic polymer foams. The technical challenges in processing BBFs are discussed, and the most promising applications of BBFs are then considered. Full article

Driven by the growing demand for sustainable materials, spent coffee grounds have emerged as a promising bio-based reinforcement in polymer composites, particularly for additive manufacturing applications. As a readily available byproduct of the coffee industry, spent coffee grounds contain cellulose, hemicellulose, lignin, proteins, and oils, making them attractive fillers for both thermoplastic and thermoset matrices. Incorporating spent coffee grounds into composites supports waste valorization, cost reduction, and environmental sustainability by transforming organic waste into functional materials. This review first examines the issue of spent coffee ground waste, addressing its environmental footprint and disposal challenges. It then explores the composition and properties of spent coffee grounds. The paper provides a comprehensive overview of composites based on spent coffee grounds for 3D printing, covering processing methods, potential applications, and current challenges in additive manufacturing. Special attention is given to the preparation and processing of these composites, including key steps such as drying, grinding, sieving, and surface modification to enhance compatibility with polymer matrices. Various additive manufacturing techniques influence the printability, processability, and mechanical performance of such composites. While spent coffee grounds offer notable sustainability advantages, challenges such as weak interfacial adhesion, moisture sensitivity, and reduced mechanical properties necessitate optimized processing conditions, surface treatments, and tailored material formulations. This review highlights recent advancements and outlines future research directions, emphasizing the need for stronger interactions between spent coffee grounds and polymer matrices, improved recyclability, and scalable additive manufacturing solutions to establish spent coffee grounds as a viable and eco-friendly alternative for 3D printing applications. Full article

Plastic pollution has emerged as a critical environmental challenge due to the widespread accumulation of petrochemical plastics in natural ecosystems. Conventional waste management strategies, including mechanical recycling and incineration, have demonstrated limited efficiency in addressing the persistence of plastics such as polyethylene, polypropylene, polyethylene terephthalate, and polyvinyl chloride. While incineration eliminates plastic material, it does not promote circularity and may generate toxic emissions. As a sustainable alternative, microbial biodegradation involves bacteria, fungi, and actinomycetes capable of degrading synthetic polymers through enzymatic processes. This review provides a comprehensive overview of microbial degradation of major plastics such as polyethylene, polypropylene, polyethylene terephthalate, and polyvinyl chloride, highlighting key strains, degradation rates, and enzymatic mechanisms. Importantly, biodegradation research also informs the development of in situ remediation technologies and supports new recycling strategies. Advances in protein engineering and synthetic biology are discussed for enhancing degradation efficiency. However, scaling biodegradation to environmental conditions remains challenging due to variable temperature, pH, microbial competition, and potentially toxic intermediates. Despite these limitations, microbial biodegradation represents a promising ecofriendly approach to address plastic waste and promote a biobased circular economy. Future work should integrate microbial processes into existing recycling infrastructure and design robust consortia guided by omics tools. Full article

Developing high-performance bio-based epoxy resins as sustainable alternatives to petroleum-derived bisphenol A (BPA) epoxies for recyclable carbon fiber-reinforced polymers (CFRPs) is pivotal in materials research. Herein, the bio-based bisphenol monomer BDEF was synthesized from the lignin derivative 4-propylguaiacol. The derived epoxy monomer BDEF-EP was cured with adipic acid to form a bio-based vitrimer. Stress relaxation synergistically accelerates through intrinsic dynamic carboxylic acid ester exchange and enhanced chain mobility from the flexible propyl structure. At 220 °C, this vitrimer shows rapid stress relaxation (τ* < 30 s) and repairs ~90% of surface scratches in 30 min. It exhibits tensile and flexural strengths of 69 MPa and 105 MPa, respectively. BDEF-EP’s low viscosity reduces diluent needs in composite fabrication, lowering costs and improving efficiency. The resulting bio-based CFRP achieves tensile and flexural strengths of 543 MPa and 414 MPa, respectively, which are comparable to commercially available petroleum-derived CFRP. In addition, CFRP containing dynamic crosslinked networks demonstrates degradable recyclability in ethylene glycol solvent, preserving the surface morphology and chemical structure of recovered carbon fibers. The results demonstrate that this bio-based epoxy vitrimer has promising potential for developing sustainable, degradable, and recyclable CFRP composites. Full article

This study investigates the structural transformation from the γ-phase into the α-phase in bio-based nylon 5,6 fibers during in situ uniaxial stretching, using X-ray diffraction (XRD) and density functional theory (DFT) calculations. Initially, nylon 5,6 films exhibited a well-defined γ-phase crystalline structure, and the as-spun fibers also retained a γ-phase-dominant structure with partial coexistence of α-phase components. Due to the lattice similarity between the γ- and α-phases, phase separation was challenging in the direction perpendicular to the fiber axis (ab-plane). However, the analysis of the (004) diffraction peaks along the fiber axis (c-axis) enabled the quantitative evaluation of each crystalline component. As the stretching progressed, the α(004) peak intensity gradually increased, indicating a continuous γ-to-α structural transition. Furthermore, DFT calculations revealed that the α-phase has lower energy than the γ-phase, supporting the thermodynamic favorability of the phase transition during elongation. These results provide a comprehensive understanding of the crystalline structure and transformation mechanism in environmentally friendly nylon fibers from both experimental and theoretical perspectives, and offer foundational insights for developing nylon materials with desirable properties through the precise control of crystal phase structures. Full article

Active packaging supports sustainable development by extending food shelf life and reducing spoilage, contributing to global food security. In this study, cellulose dialdehyde was synthesized and blended with polyvinyl alcohol in varying ratios to produce composite films. The incorporation of dialdehyde cellulose into films tended to increase puncture strength and Young’s modulus, decrease elongation, reduce water solubility, and enhance resistance to water vapor transmission because of crosslinking. Carbon quantum dots were subsequently incorporated into composite films to enhance their antibacterial property. This represents a novel combination of a natural bio-based crosslinker and fluorescent nanomaterials in a single packaging system. Carbon quantum dots were synthesized by an electrochemical method and incorporated as functional agents. The addition of carbon quantum dots influenced the mechanical properties of the films due to interactions between polymers and carbon quantum dots. This interaction also slightly reduced the antibacterial effectiveness of the films, consisting of dialdehyde cellulose and PVA in ratios of 3:1 and 4:0. Nevertheless, the composite films maintained sufficient antimicrobial activity against common foodborne bacteria, including Staphylococcus aureus, Escherichia coli, and Salmonella Typhimurium. Overall, the findings demonstrate that multifunctional material made from dialdehyde cellulose, polyvinyl alcohol, and carbon quantum dots are a promising alternative to conventional plastic packaging. Full article

The recycling of polypropylene (PP) packaging films modified with biobased additives: biochar derived from the pyrolysis of natural fibers and diatomaceous earth was investigated. The aim was to assess the impact of these modifiers on the processing, rheological, mechanical, and thermal properties of the recycled material. The processing behavior was evaluated through extrusion with granulation to determine industrial applicability. Rheological properties, including viscosity and melt flow index (MFI), were measured to characterize flow behavior. Mechanical performance was assessed through tensile strength, hardness, three-point bending, and impact resistance tests. Thermal properties were analyzed using thermogravimetric analysis (TGA), Vicat softening temperature (VST), and differential scanning calorimetry (DSC). The results demonstrate that incorporating biochar and diatomaceous earth can modify and, in selected cases, enhance the processing and performance characteristics of recycled PP films, though their impact on thermal behavior is parameter-specific. While diatomaceous earth slightly increased the onset of thermal degradation (T₅), both fillers caused a slight decrease in the VST, indicating reduced heat resistance under load. Diatomaceous earth was found to effectively improve stiffness and impact strength, while biochar reduced viscosity and promoted finer crystalline structures. Both additives acted as nucleating agents, increasing crystallization temperatures, with diatomaceous earth additionally delaying thermal degradation onset. These findings highlight the potential of using sustainable, waste-derived additives in polymer recycling, supporting the development of environmentally responsible materials within circular economy frameworks. Full article

This study explores the valorization of Colocasia esculenta roots (flesh and peels) as a source of biopolymers by isolating and characterizing starch and cellulose nanofibers. Fresh roots were sourced from the Colombian Caribbean, and a bromatological analysis was conducted to determine their composition. Starch was extracted from the flesh (yield: 16.2 ± 0.5%) and characterized by a low amylose content (14.6 ± 0.9%) and a gelatinization temperature of 77.6 ± 0.3 °C. Granules showed spherical and polyhedral shapes and smooth, fissure-free surfaces. The median granule size (D50 = 12.2 ± 0.18 µm) exceeded several values reported for Colocasia esculenta from other regions. Cellulose nanofibers were isolated from peel byproducts (yield: 10.0 ± 1.4%), displaying dense fibrillar networks with diameters of 15–25 nm and lengths around 80 nm. FTIR analysis confirmed the presence of characteristic functional groups in both materials. Thermogravimetric analysis showed thermal degradation peaks at 320 °C for starch and 330 °C for nanocellulose. These findings demonstrate that Colocasia esculenta, an underutilized crop in the Colombian Caribbean, represents a promising and sustainable raw material for the development of bio-based polymers with suitable physicochemical, structural, and thermal properties. Full article

Fiber-reinforced composites (FRCs) have emerged as transformative alternatives to traditional marine construction materials, owing to their superior corrosion resistance, design flexibility, and strength-to-weight ratio. This review comprehensively examines the current state of FRC technologies in marine deck and underwater applications, with a focus on manufacturing methods, durability challenges, and future innovations. Thermoset polymer composites, particularly those with epoxy and vinyl ester matrices, continue to dominate marine applications due to their mechanical robustness and processing maturity. In contrast, thermoplastic composites such as Polyether Ether Ketone (PEEK) and Polyether Ketone Ketone (PEKK) offer advantages in recyclability and hydrothermal performance but are hindered by higher processing costs. The review evaluates the performance of various fiber types, including glass, carbon, basalt, and aramid, highlighting the trade-offs between cost, mechanical properties, and environmental resistance. Manufacturing processes such as vacuum-assisted resin transfer molding (VARTM) and automated fiber placement (AFP) enable efficient production but face limitations in scalability and in-field repair. Key durability concerns include seawater-induced degradation, moisture absorption, interfacial debonding, galvanic corrosion in FRP–metal hybrids, and biofouling. The paper also explores emerging strategies such as self-healing polymers, nano-enhanced coatings, and hybrid fiber architectures that aim to improve long-term reliability. Finally, it outlines future research directions, including the development of smart composites with embedded structural health monitoring (SHM), bio-based resin systems, and standardized certification protocols to support broader industry adoption. This review aims to guide ongoing research and development efforts toward more sustainable, high-performance marine composite systems. Full article

Two series of environmentally friendly polymer blends of bio-based poly(ethylene 2,5 furanoate) (PEF) and poly(butylene 2,5 furanoate) (PBF) with epoxidized natural rubber (epNR) have been prepared. Both bio-based polyesters were synthesized from dimethyl furan-2,5-dicarboxylate (DMFDC) and 1,2-ethylene glycol (EG) or 1,4-butylene glycol (BG) by a two-stage melt polycondensation process. The miscibility of the components in the blend was assessed using calculations based on Hoy’s method. The chemical interactions, presence of functional groups, miscibility, and possible reactions or cross-linking between polyesters and epNR were analyzed by Fourier Transform Infrared Spectroscopy (FTIR). A significant influence of epNR addition on the melt flow index (MFI), limited viscosity number (LVN), and apparent cross-link density values was also demonstrated. Phase transition temperatures and associated thermal phenomena in polyester/epNR blends were evaluated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Oxidation onset temperature (OOT) tests were performed to obtain valuable information about the thermal-oxidative stability of the blends. Tensile tests revealed that the addition of epNR to PEF increases flexibility but at the same time reduces stiffness and tensile strength, especially at higher contents of epNR. In the case of PBF, a gradual decrease in tensile strength and elastic modulus is observed with increasing epNR content. Additionally, hardness tests showed that the addition of epNR leads to a decrease in hardness for both PEF- and PBF-based compositions. Full article

Food packaging is an essential part of the food industry. Packaging materials are indispensable in ensuring product safety, enhancing consumer experience, and supporting sustainable practices. This review provides an update on the role of bio-based polymers, including polylactic acid (PLA), polyhydroxyalkanoates (PHAs), starch-based polymers, and cellulose-based polymers (cellulose acetate (CA), cellulose sulphate (CS), carboxymethyl cellulose (CMC), nanocellulose (NC), and methylcellulose (MC)) for food packaging applications. Properties as mechanical, barrier and antimicrobial, as well as their eco-friendly behavior, are also summarized. The advantages and disadvantages of using bio-based polymers in food packaging are discussed. Present review also addresses the challenges associated with their preparation and highlights the potential future prospects of bio-based polymers for packaging applications. Full article