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Search Results (353)

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Keywords = UV-curable

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22 pages, 3894 KiB  
Article
3D-Printed Biocompatible Frames for Electrospun Nanofiber Membranes: An Enabling Biofabrication Technology for Three-Dimensional Tissue Models and Engineered Cell Culture Platforms
by Adam J. Jones, Lauren A. Carothers, Finley Paez, Yanhao Dong, Ronald A. Zeszut and Russell Kirk Pirlo
Micromachines 2025, 16(8), 887; https://doi.org/10.3390/mi16080887 - 30 Jul 2025
Viewed by 334
Abstract
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 [...] Read more.
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 article belongs to the Special Issue Advanced Biomaterials and Biofabrication)
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18 pages, 4169 KiB  
Article
Sustainable Thermoelectric Composites: A Study of Bi2Te3-Filled Biobased Resin
by Luca Ferretti, Pietro Russo, Jessica Passaro, Francesca Nanni, Saverio D’Ascoli, Francesco Fabbrocino and Mario Bragaglia
Materials 2025, 18(15), 3453; https://doi.org/10.3390/ma18153453 - 23 Jul 2025
Viewed by 290
Abstract
In this work, bio-based thermoelectric composites were developed using acrylated epoxidized soybean oil (AESO) as the polymer matrix and bismuth telluride (Bi2Te3) as the thermoelectric filler. The materials were formulated for both UV-curing and thermal-curing processes, with a focus [...] Read more.
In this work, bio-based thermoelectric composites were developed using acrylated epoxidized soybean oil (AESO) as the polymer matrix and bismuth telluride (Bi2Te3) as the thermoelectric filler. The materials were formulated for both UV-curing and thermal-curing processes, with a focus on Digital Light Processing (DLP) 3D printing. Although UV curing proved ineffective at high filler concentrations due to the light opacity of Bi2Te3, thermal curing enabled the fabrication of stable, homogeneously dispersed composites. The samples were thoroughly characterized through rheology, FTIR, TGA, XRD, SEM, and density measurements. Thermoelectric performance was assessed under a 70 °C temperature gradient, with Seebeck coefficients reaching up to 51 µV/K. Accelerated chemical degradation studies in basic media confirmed the degradability of the matrix. The results demonstrate the feasibility of combining additive manufacturing with sustainable materials for low-power thermoelectric energy harvesting applications. Full article
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21 pages, 903 KiB  
Article
Preliminary Analysis of Printed Polypropylene Foils and Pigments After Thermal Treatment Using DSC and Ames Tests
by Lukas Prielinger, Eva Ortner, Martin Novak, Lea Markart and Bernhard Rainer
Materials 2025, 18(14), 3325; https://doi.org/10.3390/ma18143325 - 15 Jul 2025
Viewed by 330
Abstract
In order to recycle plastic waste back to food contact materials (FCMs), it is necessary to identify hazardous substances in plastic packaging that pose a toxicological risk. Printing inks on plastics are not yet designed to withstand the high heat stress of mechanical [...] Read more.
In order to recycle plastic waste back to food contact materials (FCMs), it is necessary to identify hazardous substances in plastic packaging that pose a toxicological risk. Printing inks on plastics are not yet designed to withstand the high heat stress of mechanical recycling processes and therefore require hazard identification. In this study, virgin polypropylene (PP) foils were printed with different types of inks (UV-cured, water-based) and colour shades. Thermal analysis of printed foils and pigments was performed using differential scanning calorimetry (DSC). Samples were then thermally treated below and above measured thermal events at 120 °C, 160 °C, 200 °C or 240 °C for 30 min. Subsequently, migration tests and miniaturised Ames tests were performed. Four out of thirteen printed foils and all three pigments showed positive results for mutagenicity in miniaturised Ames tests after thermal treatment at 240 °C. Additionally, pre-incubation Plate Ames tests (according to OECD 471) were performed on three pigments and one printed foil, yielding two positive results after thermal treatment at 240 °C. These results indicate that certain ink components form hazardous decomposition products when heated up to a temperature of 240 °C. However, further research is needed to gain a better understanding of the chemical processes that occur during high thermal treatment. Full article
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20 pages, 3251 KiB  
Review
Chemical Functionalization of Camelina, Hemp, and Rapeseed Oils for Sustainable Resin Applications: Strategies for Tailoring Structure and Performance
by Elham Nadim, Pavan Paraskar, Emma J. Murphy, Mohammadnabi Hesabi and Ian Major
Compounds 2025, 5(3), 26; https://doi.org/10.3390/compounds5030026 - 10 Jul 2025
Viewed by 294
Abstract
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. [...] Read more.
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
(This article belongs to the Special Issue Compounds–Derived from Nature)
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25 pages, 5693 KiB  
Review
Research Progress on Vegetable Oil-Based UV-Curing Resins
by Wei Wang, Zhengru Hu and Wen Lei
Polymers 2025, 17(14), 1890; https://doi.org/10.3390/polym17141890 - 8 Jul 2025
Viewed by 475
Abstract
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 [...] Read more.
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
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21 pages, 5905 KiB  
Article
Tellurium-Doped Silanised Bioactive Glass–Chitosan Hydrogels: A Dual Action for Antimicrobial and Osteoconductive Platforms
by Matteo Bergoglio, Ziba Najmi, Federica Ferla, Alessandro Calogero Scalia, Andrea Cochis, Lia Rimondini, Enrica Vernè, Marco Sangermano and Marta Miola
Polymers 2025, 17(12), 1651; https://doi.org/10.3390/polym17121651 - 13 Jun 2025
Cited by 1 | Viewed by 760
Abstract
UV-cured methacrylated chitosan (MCHIT) hydrogels were achieved in the presence of silanised tellurium-doped silica bioactive glass (BG-Te-Sil) to produce an antimicrobial and osteoconductive scaffold for tissue engineering applications. Methacrylation of chitosan enabled efficient crosslinking, and the curing process was evaluated by means of [...] Read more.
UV-cured methacrylated chitosan (MCHIT) hydrogels were achieved in the presence of silanised tellurium-doped silica bioactive glass (BG-Te-Sil) to produce an antimicrobial and osteoconductive scaffold for tissue engineering applications. Methacrylation of chitosan enabled efficient crosslinking, and the curing process was evaluated by means of Fourier-transform infrared spectroscopy (FTIR) and photorheology analyses. Compressive testing on crosslinked hydrogels showed that the silanised, bioactive, doped glass increased the hydrogel’s elastic modulus by up to 200% compared to unreinforced controls. Antibacterial assays against Staphylococcus aureus ATCC 43300 revealed a significant (p < 0.05) reduction in bacterial metabolic activity for hydrogels containing 50 wt% of the Te-doped bioactive glass. In vitro cytocompatibility with human bone-marrow mesenchymal stem cells demonstrated sustained viability and uniform distribution at 72 h (live/dead staining, AlamarBlue). Under H2O2-induced oxidative stress, reinforced hydrogels downregulated pro-inflammatory genes (TNF-α, IFN-γ, IL-1β, and PGES-2). These results suggest that the presence of the silanised bioactive glass can significantly enhance mechanical stability, antibacterial properties, and anti-inflammatory responses without affecting cytocompatibility, making these hydrogels promising for tissue engineering applications. Full article
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24 pages, 4310 KiB  
Article
Thermal and Chemical Characterization of Digital Light Processing (DLP)-Manufactured Polymer Composites Reinforced with Jute Fibers
by Raí Felipe Pereira Junio, José Carlos Ferreira Fontes, Douglas Santos Silva, Bernardo Soares Avila de Cêa, Sergio Neves Monteiro and Lucio Fabio Cassiano Nascimento
Polymers 2025, 17(11), 1504; https://doi.org/10.3390/polym17111504 - 28 May 2025
Cited by 1 | Viewed by 470
Abstract
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 [...] Read more.
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
(This article belongs to the Section Polymer Composites and Nanocomposites)
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17 pages, 4659 KiB  
Article
Effects of Gamma Irradiation on Solid Propellant Conventional and UV-Cured Binders
by Stefania Carlotti, Rocco Carcione, Beatrice D’Orsi, Tommaso Lusetti, Alessandro Finazzi, Jessica Scifo, Ilaria Di Sarcina, Matteo Ferrari, Alessia Cemmi and Filippo Maggi
Aerospace 2025, 12(6), 471; https://doi.org/10.3390/aerospace12060471 - 27 May 2025
Viewed by 482
Abstract
Ionizing radiations are responsible for bond scission, radical formation, and oxidative degradation of polymer matrices. This study focuses on the effects of gamma irradiation on solid propellant binders, targeting a comprehensive chemical and mechanical characterization of different formulations. Samples were produced either by [...] Read more.
Ionizing radiations are responsible for bond scission, radical formation, and oxidative degradation of polymer matrices. This study focuses on the effects of gamma irradiation on solid propellant binders, targeting a comprehensive chemical and mechanical characterization of different formulations. Samples were produced either by conventional methods based on hydroxyl-terminated polybutadiene and standard polyaddition reaction using isocyanates, or innovative approaches involving UV-driven radical curing. The samples were irradiated for comparison and to study their evolution as a function of three absorbed doses (25, 45, 130 kGy) for preliminary characterization studies, using a 60-Co gamma source. Samples were irradiated in air at uncontrolled room temperature. The coupling of spectroscopy techniques (Fourier transform infrared—FTIR, Raman and electron paramagnetic resonance—EPR) and dynamic mechanical analysis (DMA) highlighted the key role of antioxidant agents in tailoring mechanical changes in the binder phase. The absence of antioxidants enhances radical formation, oxidation, and cross-linking. These processes lead to progressively increased rigidity and reduced flexibility as a function of the absorbed dose. Complex interactions between photocured components largely influence radical stabilization and material degradation. These findings provide valuable insights for designing novel radiation-resistant binders, enabling the development of solid propellants tailored for reliable, long-term permanence in space, and advancing the knowledge on the applicability of 3D-printed propellants. Full article
(This article belongs to the Section Astronautics & Space Science)
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16 pages, 1492 KiB  
Article
The Effect of Photoreactive Diluents on the Properties of a Styrene-Free Vinyl Ester Resin for Cured-In-Place Pipe (CIPP) Technology
by Małgorzata Krasowska, Agnieszka Kowalczyk, Krzysztof Kowalczyk, Rafał Oliwa and Mariusz Oleksy
Materials 2025, 18(10), 2304; https://doi.org/10.3390/ma18102304 - 15 May 2025
Viewed by 455
Abstract
Cured-in-place pipe (CIPP) technology is a trenchless rehabilitation method for damaged pipelines in which a resin-saturated liner (often a fiber-reinforced type) is inserted into a host pipe and cured in situ, typically using a UV light beam or steam. This study investigates the [...] Read more.
Cured-in-place pipe (CIPP) technology is a trenchless rehabilitation method for damaged pipelines in which a resin-saturated liner (often a fiber-reinforced type) is inserted into a host pipe and cured in situ, typically using a UV light beam or steam. This study investigates the influence of selected photoreactive diluents on the photopolymerization process of a styrene-free vinyl ester resin designed for the CIPP applications by evaluating the rheological properties, photopolymerization kinetics (photo-DSC), thermal characteristics (DSC), crosslinking density (gel content), and mechanical properties of thick (15 mm) UV-cured layers. The tested diluents included monofunctional (i.e., methyl methacrylate and vinyl neodecanoate), difunctional (1,6-hexanediol diacrylate, aliphatic urethane acrylates, and an epoxy acrylate), and trifunctional monomers (trimethylolpropane triacrylate, pentaerythritol triacrylate, and trimethylolpropane ethoxylate triacrylate). The key findings demonstrate that the addition of pentaerythritol triacrylate (the most attractive diluent) increases the flexural strength (+6%) and deflection at strength (+28%) at the unchanged flexural modulus value (ca. 2.1 GPa). The difunctional epoxy acrylate caused an even greater increase in the deflection (+52%, at a 5% increase in the flexural strength). Full article
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12 pages, 13721 KiB  
Article
Description of Paper–UV-Curable Thermochromic Ink Interactions with Surface-Free Energy Measurements
by Marina Vukoje, Rahela Kulčar and Tomislav Cigula
Macromol 2025, 5(2), 22; https://doi.org/10.3390/macromol5020022 - 6 May 2025
Viewed by 764
Abstract
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 [...] Read more.
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
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13 pages, 5284 KiB  
Communication
Electrohydrodynamically Printed Microlens Arrays with the High Filling Factor near 90%
by Linkun Zhong, Weixuan Liu, Hongbo Gong, Ye Li, Xueqian Zhao, Delai Kong, Qingguo Du, Bing Xu, Xiaoli Zhang and Yan Jun Liu
Photonics 2025, 12(5), 446; https://doi.org/10.3390/photonics12050446 - 5 May 2025
Viewed by 387
Abstract
Microlens arrays (MLAs) are essential for light collection, extraction, and high-resolution imaging. However, most reported MLAs have a limited filling factor. Here, we demonstrate MLAs using three different UV-curing optical adhesives based on the electrohydrodynamic inkjet (E-jet) printing technique. The highest filling factor [...] Read more.
Microlens arrays (MLAs) are essential for light collection, extraction, and high-resolution imaging. However, most reported MLAs have a limited filling factor. Here, we demonstrate MLAs using three different UV-curing optical adhesives based on the electrohydrodynamic inkjet (E-jet) printing technique. The highest filling factor of 89.91% is achieved. By controlling the curvature of the microlens via the surface treatment of the substrate, a series of MLAs with different numerical apertures can be obtained. With the high-consistency printing technique, the demonstrated high filling factor MLAs could be potentially useful to improve the performance of optical imaging and sensing systems. Full article
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24 pages, 4250 KiB  
Article
Interactions and Curing Dynamics Between UV-Triggered Epoxy Acrylate Binder, Curing Agents and Photoinitiators
by Ji-min Choi, Sang Jang and Keon-Soo Jang
Polymers 2025, 17(9), 1252; https://doi.org/10.3390/polym17091252 - 4 May 2025
Viewed by 850
Abstract
This study investigated the interaction between UV-triggered curing binders and photoinitiators, focusing on their thermal, mechanical, and morphological properties. Using epoxy acrylate as the matrix and three potential photoinitiators with varying phosphorus contents, UV curing systems were fabricated and analyzed. 2-hydroxy-2-methyl-1-phenyl-1-propanone (HMPP), 2,4,6-trimethyl [...] Read more.
This study investigated the interaction between UV-triggered curing binders and photoinitiators, focusing on their thermal, mechanical, and morphological properties. Using epoxy acrylate as the matrix and three potential photoinitiators with varying phosphorus contents, UV curing systems were fabricated and analyzed. 2-hydroxy-2-methyl-1-phenyl-1-propanone (HMPP), 2,4,6-trimethyl benzoyl diphenyl phosphine oxide (TPO), and their mixture were utilized as photoinitiators. We observed that the curing process significantly reduced residual double bonds within the first 5 s of UV irradiation time. The glass transition temperature (Tg) increased with curing time due to enhanced network density. For instance, in the MyA–TPO formulation, Tg of the cured sample tended to increase to 67.3 °C for 3 s to 79.8 °C for 15 s. Mechanical analysis revealed that HMPP facilitated the formation of robust network structures. Notably, the MyA–HMPP formulation exhibited a tensile strength of 63 MPa and a Young’s modulus of 21 MPa, indicating excellent mechanical strength. SEM imaging confirmed these findings, illustrating distinct fracture morphologies that correlated with mechanical performance. These results provide insights into optimizing UV-curable materials for applications requiring high precision and durability. In particular, the combination of high Tg, superior tensile strength, and uniform fracture morphology indicates excellent thermal stability, mechanical integrity, and crack resistance—critical requirements in semiconductor packaging. These properties, along with rapid UV curing, support the suitability of the proposed systems for advanced applications such as system-in-package (SiP) and 3D integration. Full article
(This article belongs to the Special Issue Advanced Epoxy-Based Materials, 5th Edition)
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15 pages, 3082 KiB  
Article
New Test Methods for Extractables in No-Wipe Topcoat Gel Polish: Extraction and Quantitation of Uncured Monomers After UV Curing
by Laurisa London-Dawodu, Xuejun J. Yin and Sunan Yuvavanich
Cosmetics 2025, 12(3), 89; https://doi.org/10.3390/cosmetics12030089 - 1 May 2025
Viewed by 793
Abstract
Background: Nail gels are decorative fingernail coatings based on (meth)acrylates that are photopolymerized on the nail surface. After polymerization, these coatings typically retain an uncured layer of monomers at the air interface due to oxygen inhibition, which may pose a risk of skin [...] Read more.
Background: Nail gels are decorative fingernail coatings based on (meth)acrylates that are photopolymerized on the nail surface. After polymerization, these coatings typically retain an uncured layer of monomers at the air interface due to oxygen inhibition, which may pose a risk of skin sensitization unless removed. No-wipe topcoats are formulated to address this issue by curing fully; however, no standard test method exists to verify a complete cure. This study presents a method to quantify residual uncured traces of several common nail gel monomers extracted from polymerized commercial no-wipe nail gels. Method: Commercially available no-wipe nail gels were formed into films of controlled thickness and polymerized using a standard UV-curing nail lamp. Solvent extraction was employed to eliminate residual uncured monomers, namely diethylene glycol dimethacrylate (DEGDMA), isobornyl acrylate (IBOA), and 2-hydroxyethyl methacrylate (HEMA). These monomers were quantified utilizing GC-FID and HPLC techniques. Method validation was conducted with samples of known monomer identity and concentration, thereby establishing specificity, linearity, precision, and detection limits. Results: Validated test protocols were established for the analysis of residual uncured traces of three commonly used monomers in nail gel coatings. In all instances, levels of monomer residue in a cured gel coating were found to range from 56 µg/g to 800 µg/g. Tests conducted on commercial products indicated that levels of these monomers fell within the expected normal ranges for such products. Conclusions: Through the utilization of two chromatographic techniques, three analytical methods were established for the simultaneous determination of ingredient concentrations and residual monomer quantities in unreacted bulk formula and cured UV-gel film. These methods and the resultant data facilitate the evaluation of curing completeness, which is essential for product development and safety assessments. Full article
(This article belongs to the Section Cosmetic Technology)
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18 pages, 5271 KiB  
Article
Advancing High-Performance Composites in Additive Manufacturing (AM) Through Pre-Impregnation and Direct Ink Writing for Scalable 3D Printing
by Yuanrui Wang, Yuchen Ding, Kai Yu and Guoying Dong
J. Compos. Sci. 2025, 9(5), 218; https://doi.org/10.3390/jcs9050218 - 29 Apr 2025
Viewed by 997
Abstract
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 [...] Read more.
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
(This article belongs to the Special Issue Additive Manufacturing of Advanced Composites, 2nd Edition)
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11 pages, 3846 KiB  
Article
2K UV- and Sunlight-Curable Waterborne Polyurethane Coating Through Thiol-Ene Click Reaction
by Zichen Ling, Haoran Wang and Qixin Zhou
J. Compos. Sci. 2025, 9(5), 217; https://doi.org/10.3390/jcs9050217 - 29 Apr 2025
Viewed by 615
Abstract
Waterborne polyurethane (WPU) coatings have gained significant attention in the industry due to their low environmental impact and excellent properties. Furthermore, the UV-curing system reduces energy costs and enhances curing efficiency. Hence, exploring the UV-curable WPU system is essential for advancing the next [...] Read more.
Waterborne polyurethane (WPU) coatings have gained significant attention in the industry due to their low environmental impact and excellent properties. Furthermore, the UV-curing system reduces energy costs and enhances curing efficiency. Hence, exploring the UV-curable WPU system is essential for advancing the next generation of coatings. In this study, a 2K WPU system was developed by functionalizing isocyanate-terminated polyurethane with thiol and vinyl groups. The coating was cured under UV light through a thiol-ene click reaction, and the effects of photoinitiator content on the coating performance were investigated. The feasibility of sunlight curing for this WPU coating was also assessed. The results showed that while photoinitiator content had a slight impact on UV-cured WPU coatings, it significantly affected sunlight-cured WPU. Also, with the appropriate photoinitiator content, sunlight-cured WPU could achieve comparable performance to UV-curable ones. Full article
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