Search Results (94)

Electrospun nanofiber membranes (ESNFMs) are exceptional biomaterials for tissue engineering, closely mimicking the native extracellular matrix. However, their inherent fragility poses significant handling, processing, and integration challenges, limiting their widespread application in advanced 3D tissue models and biofabricated devices. This study introduces a novel and on-mat framing technique utilizing extrusion-based printing of a UV-curable biocompatible resin (Biotough D90 MF) to create rigid, integrated support structures directly on chitosan–polyethylene oxide (PEO) ESNFMs. We demonstrate fabrication of these circular frames via precise 3D printing and a simpler manual stamping method, achieving robust mechanical stabilization that enables routine laboratory manipulation without membrane damage. The resulting framed ESNFMs maintain structural integrity during subsequent processing and exhibit excellent biocompatibility in standardized extract assays (116.5 ± 12.2% normalized cellular response with optimized processing) and acceptable performance in direct contact evaluations (up to 78.2 ± 32.4% viability in the optimal configuration). Temporal assessment revealed characteristic cellular adaptation dynamics on nanofiber substrates, emphasizing the importance of extended evaluation periods for accurate biocompatibility determination of three-dimensional scaffolds. This innovative biofabrication approach overcomes critical limitations of previous handling methods, transforming delicate ESNFMs into robust, easy-to-use components for reliable integration into complex cell culture applications, barrier tissue models, and engineered systems. Full article

This review examines the chemical functionalization of Camelina, hemp, and rapeseed oils for the development of sustainable bio-based resins. Key strategies, including epoxidation, acrylation, and click chemistry, are discussed in the context of tailoring molecular structure to enhance reactivity, compatibility, and material performance. Particular emphasis is placed on overcoming the inherent limitations of vegetable oil structures to enable their integration into high-performance polymer systems. The agricultural sustainability and environmental advantages of these feedstocks are also highlighted alongside the technical challenges associated with their chemical modification. Functionalized oils derived from Camelina, hemp, and rapeseed have been successfully applied in various resin systems, including protective coatings, pressure-sensitive adhesives, UV-curable oligomers, and polyurethane foams. These advances demonstrate their growing potential as renewable alternatives to petroleum-based polymers and underline the critical role of structure–property relationships in designing next-generation sustainable materials. Ultimately, the objective of this review is to distill the most effective functionalization pathways and design principles, thereby illustrating how Camelina, hemp, and rapeseed oils could serve as viable substitutes for petrochemical resins in future industrial applications. Full article

As a large class of natural organic compounds, vegetable oil is generally composed of 95% fatty acid triglycerides and very few complex non-triglycerides. It has many advantages, such as sufficient yield, low price, distinct structural characteristics, and biodegradability. UV curing technology is known as a new method for the green industry in the 21st century due to its high efficiency, economy, energy conservation, high adaptability, and environmental friendliness. Therefore, UV-curable resins based on UV-curing technology has attracted widespread attention, converting epoxy soybean oil, castor oil, tung oil and other vegetable oils into high-performance plant oil-based UV-curable resins with higher molecular weight, multi-rigid ring and high reactivity, and the curing performance has been greatly improved, and the technology has been widely used in the field of polymer materials such as coatings, inks and adhesives. In this article, the recent research progress on this topic was summarized, and emphasis was put on the research on the resins from soybean oil and castor oil. Full article

The growing demand for sustainable materials with tunable thermal and structural properties has driven the development of composites reinforced with natural fibers in additive manufacturing (AM) technologies. This study investigates the thermal and chemical behavior of polymer composites produced via Digital Light Processing (DLP), an AM technique based on vat photopolymerization that stands out for its high resolution, dimensional control, and superior speed compared to methods such as FDM and SLA. Samples were manufactured with a UV-curable acrylate resin reinforced with jute fibers (Corchorus capsularis) in mass fractions of 0%, 2%, 2.5%, and 3% in solid geometries (CS-). TGA indicated a 4% reduction in the initial degradation temperature with increasing fiber content, from 326.3 °C (CS-0) to 313.2 °C (CS-3.0). TMA revealed a reduction of up to 19% in the coefficients of thermal expansion, indicating greater dimensional stability. The DMA indicated a 16.9% decrease in the storage modulus with 3% fibers, evidencing changes in the viscoelastic response. FTIR detected additional bands at 3340 cm⁻¹ and 1030 cm⁻¹, related to O–H and polysaccharides, confirming a fiber–matrix chemical interaction. These results demonstrate the potential of jute as a sustainable reinforcement in photopolymerizable resins, paving the way for ecological and functional applications in 3D-printed composites. Full article

The adhesion of printing inks to printing substrates is a complex process influenced by both the physical and chemical properties of the printing substrate and of the printing ink. Synthetic paper, being a polymer with no absorption capability, limits the interaction between the ink and substrate, leading to lower adhesion values. On synthetic paper, the thicker polymer resin layer covering the microcapsules results in a more stable ink film and lighter print coloration. In contrast, UV-curable ink applied to bulky and recycled papers, which have porous structures, exhibits more dynamic interactions. The polymer resin in the ink penetrates the paper’s pores, forming a stronger bond with the paper fibers and improving adhesion quality. Surface roughness also plays a significant role in ink adhesion. Rough surfaces increase contact between ink and paper, enhancing mechanical adhesion by allowing the ink to “lock” into the surface’s irregularities. The surface energy (SFE) at the interphase between paper and ink is also a key factor. Low SFE promotes better wetting and ink absorption, improving adhesion. Ink penetration into the printing substrate is crucial for achieving high-quality adhesion. Full article

Additive manufacturing (AM) has the potential to revolutionize the fabrication of continuous carbon fiber-reinforced polymer composites (CCFRPCs). Among AM techniques, direct ink writing (DIW) with ultraviolet (UV) curable resin shows promise for creating CCFRPCs with high manufacturing speed, high fiber volume fraction, and low energy consumption. However, issues such as incomplete curing and weak interfacial bonding, particularly in dense fiber bundles, limit the mechanical performance. This study addressed these challenges using pre-impregnated systems (PISs), which is a process developed to impregnate dry fiber bundles with partially cured resin before being used for DIW printing, to enhance resin-fiber adhesion and fiber–fiber bonding within fiber bundles. By optimizing resin viscosity and curing conditions in the PIS process, samples treated by PIS achieved improved mechanical properties. Tensile and bending tests revealed significant performance gains over non-PIS treated samples, with tensile stiffness increasing by at least 39% and bending stiffness by 45% in 3K fiber bundles. Tensile samples with thicker fiber bundles (6K and 12K) exhibited similar improvements. On the other hand, while all samples exhibit enhanced mechanical properties under bending deformation, the improvement of flexural stiffness and strength with thicker fiber bundles is shown to be less significant than those with 3K fiber bundles. Overall, composites made with PIS-treated fibers can enhance mechanical performance compared with those made with non-PIS-treated fibers, offering the scaling capability of printing thicker fiber bundles to reduce processing time while maintaining improved properties. It emphasizes the importance of refining the pre-processing strategies of large continuous fiber bundles in the AM process to achieve optimal mechanical properties. Full article

The introduction of side-emitting lenses into white light-emitting diodes (LEDs) has enabled thin panel lighting technology based on LED technology, but also presents the disadvantage of low color rendering due to insufficient red components in the spectra of typical white LEDs. Additional application of remote quantum dot (QD) components such as QD films or caps presents the issues of increased numbers of components and higher costs. In this study, we incorporated red QDs directly into a lens placed on white LEDs and analyzed the effects of QD lenses on the optical characteristics of a lighting device through experiments and simulations. By incorporating red CdSe/ZnS QDs into UV-curable resin to fabricate QD lenses and applying them to white LEDs, we significantly improved the color rendering index and were able to adjust the correlated color temperature over a wide range between 2700 and 9900 K. However, as the concentration of QDs in the lens increased, scattering by the QD particles was enhanced, strengthening the Lambertian distribution in the intensity plot. Following the development of optical models for QD lenses under experimental conditions, comprehensive optical simulations of white LED lighting systems revealed that increasing the device height proved more effective than modifying TiO₂ scattering particle concentration in the diffuser plate for mitigating QD-induced bright spots and enhancing illumination uniformity. Full article

Coatings can achieve the property of changing color with temperature variations by adding thermochromic microcapsules, which can bring a variable surface to the substrate. Ultraviolet ray (UV)-cured primers have the advantages of a fast curing rate, low-temperature curing, and low pollution. Thermochromic microcapsules can expand the application range of UV primers. Thermochromic microcapsules were synthesized through an orthogonal test, using crystal violet lactone, bisphenol A, and decanol as the core materials in a 1:4:50 mass ratio, with urea formaldehyde resin as the wall material. The effects of the addition of batches of the urea, the mass ratio of the formaldehyde solution to the urea, the hydrophilic–lipophilic balance (HLB) value of the emulsifier, and core-to-wall mass ratio on microcapsules yields, encapsulation rates, thermochromic color differences (ΔE), and formaldehyde releases during synthesis were investigated. The results were normalized, with the thermochromic ΔE as the primary reference for analysis. The results indicate that the HLB value of the emulsifier was the key factor that affected the microcapsule performance. In a single-factor test, the HLB value was adjusted within the range of 6.00 to 10.00. It was found that when the HLB value was 10.00, the microcapsules exhibited the best comprehensive performance, with a yield of 43.29%, an encapsulation rate of 45%, a thermochromic ΔE of 4.60, and a formaldehyde concentration released of 1.310 mg/L. The 11# microcapsules with the optimal morphology and better comprehensive performance were compared with the best 14# microcapsules. Different amounts of these microcapsules were added to the UV primer to investigate the effects of the 11# and 14# microcapsules on the mechanical and optical properties of the UV primer. The main component of the UV primer was polyurethane acrylic resin, propylene glycol diacrylate, and hexanediol diacrylate. When 14# microcapsules were added to the UV primer at a concentration of 10%, the primer exhibited the best comprehensive performance, with a fracture elongation of 17.44%, a roughness of 0.15 μm, and a visible light transmittance of 83%. Microcapsule technology was used to modify UV primers, endowing them with thermochromic properties and expanding the application range of thermochromic microcapsules. Full article

Double-base (DB) propellants, renowned for their superior performance and cost-effectiveness, are extensively utilized in both rocketry and artillery applications. During the 3D printing process of double-base propellants, auxiliary solvents play a crucial role in plasticizing the DB propellant mixtures. Consequently, the printed propellants are prone to significant shrinkage and dimensional instability as a result of solvent evaporation post-printing. To address these challenges, we have innovated a UV-assisted material extrusion 3D printing technique that preserves the intended geometries of the DB propellant. The results of our printing trials indicate that incorporating an energetic UV-curable resin as a modifier into the DB propellant paste is highly effective. Ultimately, we successfully fabricated a porous propellant cylinder featuring a periodic woodpile structure. Additionally, the internal structure, mechanical properties, combustion characteristics, and in-barrel ballistic performance of the printed propellants have been thoroughly characterized. Our findings underscore that the UV-assisted material extrusion additive manufacturing process confers exceptional properties to the DB propellant. Full article

Radiative cooling is a passive cooling strategy that dissipates heat externally through the atmospheric window (8–13 μm). This study presents a radiative cooling film with a simple and cost-effective fabrication process. The film was fabricated by mixing SiO₂ hollow microspheres with a UV-curable resin, employing a photopolymerization-induced phase separation method. The resulting gradient refractive index structure enhanced thermal radiation emissivity. At an optimal silica-to-resin mass ratio of 1:1.5 and a film thickness of 1.1 mm, the film achieved a solar reflectivity of 85% and an emissivity of 91% within the atmospheric window. Outdoor experiments conducted in both summer and winter demonstrated stable cooling performance. Under a solar irradiance of 796.9 W/m² (summer), the film reduced surface temperature by 10 °C compared to ambient air and 20 °C compared to an uncoated glass substrate, achieving a radiative cooling power of 76.7 W/m². In winter (solar irradiance of 588.8 W/m²), the film maintained a significant cooling effect, though with reduced efficiency due to lower solar exposure. Furthermore, long-term stability tests over six months showed that the film retained high solar reflectivity and infrared emissivity, indicating good durability. Overall, the developed radiative cooling films demonstrate excellent optical properties, structural stability, and cooling efficiency, making it a promising candidate for real-world radiative cooling applications. Further studies on environmental resilience and optimization under diverse climatic conditions are necessary for broader deployment. Full article

This study presents a novel self-healing mechanism for porcelain ceramics using UV-curable resin to address the inherent brittleness of ceramic materials. A biomimetic double-layered structure was designed, consisting of a high-density outer layer for mechanical strength and a highly porous inner layer for resin storage. The porous layer, achieved through nylon microparticle addition and subsequent volatilization during sintering, reached a porosity of 67%. As confirmed by FT-IR spectroscopy and EDS analysis, UV-curable acrylic resin was successfully incorporated into the porous structure. Three-point bending tests demonstrated efficient healing with a recovery rate of 56% after 5 min of UV irradiation. Both cured resin weight and post-healing bending strength increased logarithmically with UV irradiation time. The bending strength after healing was strongly dependent on the cured resin weight and polymerization depth within the specimen, as evidenced by the correlation between increased polymerization area and higher bending strength. This approach offers a promising solution for developing more reliable and durable ceramic materials, which will be particularly beneficial for aerospace and medical applications where maintenance cost reduction and extended product life are crucial. Full article

Using 3D-printed (3DPd) polymers and their composites as shape memory materials in various smart engineering applications has raised the demand for such functionally graded sustainable materials. This study aims to investigate the viscoelastic, shape memory, and fracture toughness properties of the epoxy-based ultraviolet (UV)-curable resin. A UV-based DLP (Digital Light Processing) printer was employed for the 3D printing (3DPg) epoxy-based structures. The effect of the hydrothermal accelerated ageing on the various properties of the 3DPd components was examined. The viscoelastic performance in terms of glass transition temperature (T_g), storage modulus, and loss modulus was evaluated. The shape memory polymer (SMP) performance with respect to shape recovery and shape fixity (programming the shape) were calculated through dynamic mechanical thermal analysis (DMTA). DMTA is used to reveal the molecular mobility performance through three different regions, i.e., glass region, glass transition region, and rubbery region. The shape-changing region (within the glass transition region) between the T_g value from the loss modulus and the T_g value from the tan(δ) was analysed. The temperature memory behaviour was investigated for flat and circular 3DPd structures to achieve sequential deployment. The critical stress intensity factor values of the single-edge notch bending (SENB) specimens have been explored for different crack inclination angles to investigate mode I (opening) and mixed-mode I/III (opening and tearing) fracture toughness. This study can contribute to the development of highly complex shape memory 3DPd structures that can be reshaped several times with large deformation. Full article

Effective high-aspect-ratio molds that minimize vacuum processes are becoming increasingly important for producing metalenses and other devices. To fabricate a high-aspect-ratio structure, a metal film must be used as a mask for dry etching, typically achieved via vacuum deposition. To avoid this vacuum process, we devised a method to develop an etching mask in the air using silver ink. The manufacturing method involved filling the mold with silver ink, baking it, removing silver from the convex parts of the mold with a polyethylene terephthalate film, and placing silver from the concave parts of the mold on top of the ultraviolet (UV)-cured resin using ultraviolet-nanoimprint lithography. The transferred pattern had silver on the convex parts, which was used as a mask for the oxygen dry etching of the UV-curable resin. Consequently, high-aspect-ratio resin shapes were obtained from three types of nano- and micromolds. Additionally, a high-aspect-ratio resin with silver was used as a replica mold to form a silver pattern. This process is effective and allows high-aspect-ratio patterns to be obtained from master molds. Full article

A novel monomer, 9-bis[4-(2-hydroxyethoxy)phenyl]fluorene di(mercaptopropionate), with a highly refractive index, purity, and excellent UV-curable properties, is synthesized through an optimized Fischer esterification process, reacting 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene with 3-mercaptopropionic acid. The structural characterization of this monomer is performed using Fourier-transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, high-performance liquid chromatography, and liquid chromatography-mass spectrometry. The synthesis conditions are optimized using a design-of-experiments approach. UV-curable resins are obtained by incorporating the synthesized monomer as the thiol component. The effects of thiol content on the UV-curing behavior, refractive index, shrinkage, adhesion to the polyethylene terephthalate (PET) foil, and viscoelastic recovery are examined. The thermal properties are assessed using differential scanning calorimetry and thermogravimetric analysis. Field-emission scanning electron microscopy confirms the successful replication of the prism film. In edge-lit light-emitting diode (LED) backlight units, the prism film showed increased luminance with higher thiol monomer content in the UV-curable resin while maintaining stable color coordinates. This novel highly refractive index monomer can be utilized in luminance-enhancing prism films, thereby contributing to future innovations in the display film industry. Full article

UV-curable bio-based resins are widely used in the UV curing field. However, the current UV-curable bio-based resins for the application of nail polish still have the problems of too high viscosity and insufficiently excellent mechanical properties. In this study, a soybean oil-based acrylate photosensitive resin is synthesized by using epoxidized soybean oil as a raw material and reacting it with acrylic acid. The results show that the viscosity of soybean oil-based acrylate can achieve 8.31 Pa∙s, and the UV-cured film prepared by soybean oil-based acrylate and anhydride derivatives can obtain a tensile strength of 35.36 MPa and an elongation at break of 67.8%. In addition, the soybean oil-based acrylate is further reacted with isophorone diisocyanate to obtain soybean oil-based polyurethane acrylate, which can be thermally stable at 90 °C for 7 d. And then, the UV-cured film constructed by soybean oil-based polyurethane acrylate and anhydride derivatives are prepared, and the elongation at the break of the cured films can be up to 320%. This work provides a solvent-free approach by using biomass raw materials to form polyurethane acrylic resins, which have promising potential in the application of nail polish. Full article