UV-curing Technology Research Articles

Tannic acid-grafted Polylactic acid films: A nonmigrating antibacterial packaging for chilled fresh meat

Antimicrobial packaging can prolong the shelf life of fresh food, but those active antimicrobial substances may leach into the food and affect its quality. To avoid this phenome, the CC double bond was first incorporated into the chemical structure of polylactic acid (PLLA) and tannic acid (TA) to prepare poly(L-LA-co-butyrate itaconate) (PLBI) and photoactive tannic acid (pTA). Then pTA-grafted PLBI (pTA-g-PLBI) films were fabricated using UV curing technology. Results showed that pTA was successfully grafted onto the surface of PLBI film and formed a uniform layer. The pTA-g-PLBI films exhibited good bacteriostatic effects of 86 %, 90 %, and 96 % on E. coli, P. fluorescens, and S. aureus, respectively. Additionally, pTA-g-PLBI packaging reduced the relative abundance of Shewanella, Psychrobacter, and Pseudomonas in chilled pork and delayed the deterioration of pork for more than 5 days.

Optimization of UV-Curable Polyurethane Acrylate Coatings with Hexagonal Boron Nitride (hBN) for Improved Mechanical and Adhesive Properties.

Polymer coatings are widely used in industries for protection, decoration, and specific applications, typically including volatile organic compounds (VOCs) to achieve low viscosity. The growing environmental concerns and the anticipated limits on fossil feedstock have driven the coating industry towards eco-friendly alternatives, with UV-curing technology emerging as a promising solution due to its energy efficiency, low-temperature operation, reduced VOC emissions, and high curing speed. Polyurethane acrylates (PUAs) are critical in UV-curable formulations, offering excellent flexibility, impact strength, optical, and adhesion properties. However, UV-cured PUA coatings face limitations in thermal stability and tensile strength, which can be addressed by incorporating fillers. This study investigates the effects of multi-functionalized hexagonal boron nitride (hBN) nanoparticles on the mechanical, thermal, optical, and adhesion properties of UV-cured PUA films and coatings for pre-coated metals. The results demonstrated that incorporating hBN nanoparticles enhanced the mechanical and thermal properties of the nanocomposite films, with optimal performance observed at 0.5% hBN loading. Despite the improved properties, the FTIR spectra indicated that the low concentration of hBN did not produce significant changes, potentially due to the overshadowing signals from the difunctional polyurethane acrylate.

Construction of fiber-reinforced composites with high-thickness: Achieving enhanced interfacial and mechanical properties through upconversion particles assisted near-infrared photopolymerizaton

Glass fiber reinforced polymer-based composites prepared by photocuring technology offer notable advantages. However, the traditional UV curing technology faces challenges in balancing curing efficiency, penetration depth, and mechanical properties when producing high-thickness fiber-reinforced composites. This study introduced a new method for crafting thick glass fiber reinforced composites via upconversion particle-assisted near-infrared photopolymerization (UCAP). Near-infrared (NIR) radiation had superior penetration in glass fiber composites system, effectively curing of specimens exceeding 20 mm in thickness. Through micro-CT and atomic force microscopy, it was verified that UCAP specimens had fewer interfacial defects and a wider interphase, making contribution to enhanced interlaminar and interfacial shear strength. Additionally, uniform curing effectively alleviated stress concentration under external forces, resulting in a 78.5 % increase in flexural strength and a 32.1 % increase in impact toughness for UCAP specimens compared to UV-cured ones. This approach facilitated rapid outdoor curing of large-sized glass fiber composites with sustained structural stability, showcasing the potential application of UCAP in high-performance glass fiber composites rapid prototyping.

High stretchable and self-adhesive multifunctional hydrogel for wearable and flexible sensors

Ionic conductive hydrogel has recently garnered significant research attention due to its potential applications in the field of wearable and flexible electronics. Nonetheless, the integration of multifunctional and synergistic advantages, including reliable electronic properties, high swelling capacity, exceptional mechanical characteristics, and self-adhesive properties, presents an ongoing challenge. In this study, we have developed an ionic conductive hydrogel through the co-polymerization of 4-Acryloylmorpholine (ACMO) and sodium acrylate using UV curing technology. The hydrogel exhibits excellent mechanical properties, high conductivity, superior swelling capacity, and remarkable self-adhesive attributes. The hydrogel serves as a highly sensitive strain sensor, enabling precise monitoring of both substantial and subtle human motions. Furthermore, the hydrogel demonstrates the capability to adhere to human skin, functioning as a human-machine interface for the detection of physiological signals, including electromyogram (EMG) signals, with low interfacial impedance. This work is anticipated to yield a new class of stretchable and conductive materials with diverse potential applications, ranging from flexible sensors and wearable bio-electronics to contributions in the field of artificial intelligence.

A UV-curable silicone acrylate anti-smudge coating containing tertiary amines and Ti with the ability to prevent oxygen inhibition

UV curing technology has numerous advantages such as a fast curing speed, environmental friendliness, energy conservation, and thus it is widely used in industrial production and out daily life. Free-radical polymerization is the primary mechanism for UV curing technology. However, free-radical polymerization is susceptible to oxygen inhibition, which leads to incomplete curing when this approach is employed in the air. This paper describes a new silicone acrylate prepolymer, four double bonds and a tertiary amine group at each end of the prepolymers can effectively solve the oxygen inhibition. We synthesized an alkoxymethacryloxy titanium monomer (Ti-MA). This monomer was mixed with the prepolymer and UV cured, which resulted in improved coating properties. The results showed that the double bond conversion of the prepolymer reached 90.66 ± 0.5 % at 20 s, and the residual adhesion rate also exceeded 90 %. The hardness of the coating could reach pencil hardness level 4H with the addition of Ti-MA, and the water contact angle reached 104.5 ± 0.2°, as well as excellent anti-smudge and anti-fingerprint properties. This study provides a new method to solve the oxygen inhibition problem, which has a broad application prospect in the field of coatings.

Characteristics of phosphorus‑nitrogen based flame-retardant monomers for UV-curable coatings on battery PET pouches

In this study, photocurable monomers containing phosphorus–nitrogen groups were employed alongside UV curing technology to develop flame-retardant (FR) coatings pouch-type battery cells made from polyethylene terephthalate (PET). Three different monomers were synthesized: a phosphorus-containing urethane acrylate monomer (DUPPO), a phosphorus–nitrogen-containing urethane acrylate monomer (DA-Pi-U), and a phosphazene-containing phenyl methacrylate crosslinker (CP-PMA). These monomers, recognized for their flame-retardant properties, were utilized in binary and ternary coating formulations that were effectively cured via a UV-curing process. The molecular architectures of the synthesized monomers were verified through 1H and 31P nuclear magnetic resonance spectroscopy. The rheological curing behavior of the coating solutions was assessed using an oscillatory rheometer. In addition, the reactivity of the FR coating system was examined via Fourier transform infrared spectroscopy. The thermal and flame-retardant characteristics of the FR coatings were confirmed through thermogravimetric analysis, Raman spectroscopy, limiting oxygen index measurements, and scanning electron microscopy. The ternary FR coating system with CP-PMA exhibited superior thermal stability, flame retardancy, crosslinking density, and mechanical robustness, making it suitable for PET pouches. Furthermore, optimal coating conditions for the slot coating process were determined using a viscocapillary model, enhancing practical applicability in industrial settings.

“One for two” strategy to construct an organic-inorganic polymer colloid for flame-retardant modification of flax fabric and rigid polyurethane foam

Polymeric materials such as fabric and foam have high flammability which limits their application in the field of fire protection. To this end, an organic-inorganic polymer colloid constructed from carboxymethyl chitosan and ammonium polyphosphate was used to improve the flame retardancy of flax fabric (FF) and rigid polyurethane foam (RPUF) based on a “one for two” strategy. The modification processes of FF and RPUF relied on pad-dry-cure method and UV-curing technology, respectively, and the modified FF and RPUF were severally designated as CMC/APP-FF and RFR-RPUF. Flame retardancy studies showed that CMC/APP-FF and RFR-RPUF exhibited limiting oxygen index values as high as 39.4 % and 42.6 %, respectively, and both achieved self-extinguishing behavior when external ignition source was removed. Thermogravimetric analysis and cone calorimetry test confirmed that CMC/APP-FF and RFR-RPUF had good charring ability and demonstrated reduced peak heat release rate values of 90.1 % and 10.8 %, respectively, distinct from before they were modified. In addition, condensed phase analysis showed that after burning, CMC/APP-FF became an integration char structure, whereas RFR-RPUF turned into a sandwiched char structure. In summary, the “one for two” strategy reported in this work provides a new insight into the economical fabrication of flame-retardant polymeric materials.

A bionic mimosa soft robot based on a multi-responsive PNIPAM-PEGDA hydrogel composition.

Deformation plays a vital role in the survival of natural organisms. One example is that plants deform themselves to face the sun for sufficient sunlight exposure, which allows them to produce nutrients through photosynthesis. Drawing inspiration from nature, researchers have been exploring the development of 3D deformable materials. However, the traditional approach to manufacturing deformable hydrogels relies on complex technology, which limits their potential applications. In this study, we simulate the stress variations observed in the plant tissue to create a 3D structure from a 2D material. Using UV curing technology, we create a single-layer poly(N-isopropylacrylamide) hydrogel sheet with microchannels that exhibit distinct swelling rates when subjected to stimulation. After a two-step curing process, we produce a poly(N-isopropylacrylamide)-polyethylene glycol diacrylatedouble-layer structure that can be manipulated to change its shape by controlling the light and solvent content. Based on the double-layer structure, we fabricate a dual-response driven bionic mimosa robot that can perform a variety of functions. This soft robot can not only reversibly change its shape but also maintain a specific shape without continuous stimulation. Its capacity for reversible deformation, resulting from internal stress, presents promising application prospects in the biomedical and soft robotics domain. This study delivers an insightful framework for the development of programmable soft materials.

Stretchable, stable, and structural color reversible enabled by mesoscopic regulation and design for flexible photonic crystal mechanical sensors

This paper reports a flexible mechanical sensor developed by combining an opal photonic crystal and a flexible medium through UV curing technology. Under the action of external force, the deformation of the flexible medium causes the change of the photonic crystal lattice constant, which leads to the displacement of the reflection peaks, thus realizing the detection of the deformation of the film. The flexible medium is mixed by photoinitiators and polymer monomers, and its mechanical properties are directly related to the mass fraction of photoinitiators and polymer monomers. The results show that the film can reach a maximum strain of about 180% when the mass fraction of photoinitiator is 3% and the volume ratio of the polymer functional monomers is 8:2. In addition, for the responsiveness test of the sensor under tensile, the results show that at 0%, 26%, and 78% of tensile strain, its structural color is blue-shifted sequentially, and its spectral peaks are 668 nm, 535 nm, and 488 nm, respectively. Finally, the sensor is applied to the detection of acoustic waves in air, and it is found that its spectral response peaks can be obtained for acoustic waves of different frequencies (250–650 Hz), and a spectral peak at 500 Hz. This flexible photon sensor has the potential to match the acoustic resistance of water. It will greatly expand the response research of ocean exploration in the low frequency range.

Construction of high-performance solid-state electrolytes for lithium metal batteries by UV-curing technology

With high energy density and high safety, all-solid-state lithium metal batteries (ASSLMBs) are considered the most competitive next-generation energy storage batteries. In this work, different formulations of PEGDA-based solid-state electrolytes were prepared by solution flow casting and UV-irradiated in situ polymerization. Polyethylene oxide (PEO) was introduced to solve the problem of improving the flexibility of the substrate, and a 1:5 mass ratio between them was determined. Inorganic ceramic filler Li1.25Al0.25Zr1.75(PO4)3 (LAZP) and plasticizer butanedinitrile (SCN) were introduced to improve the ionic conductivity (σ) of the electrolyte. The best performing PP15-30-SCN sample showed a 40-fold improvement in room temperature ionic conductivity over PEGDA and lithium ion mobility number of 0.43. The ASSLMBs were assembled with composite electrolytes and tested at 60 °C. The polarization of PP15-30-SCN was significantly reduced, and the battery cycled stably at current densities from 0.1 to 2 C, with an average discharge specific capacity of 111.78 mAh g−1 at 1C. The average specific capacity at 1C was 111.78 mAh g−1. Meanwhile, the capacity retention rate was more than 99% after more than 70 long cycles at 0.5C.

Low-Leakage Current Core-Shell AlGaN Nanorod LED Device Operating in the Ultraviolet-B Band.

Despite the considerable potential of AlGaN-based ultraviolet-B light-emitting diodes (UV-B LEDs) in various applications such as phototherapy, UV curing, plant growth, and analytical technology, their development is still ongoing due to low luminescence efficiency. In this study, we introduced a novel epitaxial growth mechanism to effectively control the height and thickness of AlGaN multiple wells (MWs) on AlGaN nanorod structures using horizontal reactor-based metal-organic chemical vapor deposition (MOCVD). By adjusting the H2 carrier gas flow rate, we could control the growth boundary layer's thickness, successfully separating the AlGaN well and p-AlGaN layer from the substrate. Cathodoluminescence (CL) measurements confirmed the stability of the core-shell AlGaN quantum wells as a highly stable nonpolarized structure, with the wavelength peak remaining almost unchanged under various injection currents. Furthermore, transmission electron microscopy (TEM) provided clear evidence of differentiation, highlighting the distinct formation of the 275 nm AlGaN core and the 295 nm AlGaN shell structure. The developed AlGaN MW structure, characterized by these rectification features, not only demonstrated a significantly improved electroluminescence (EL) peak intensity but also exhibited a much lower leakage current compared to the conventional core-shell AlGaN structure. The newly proposed growth mechanism and advanced nonpolarized core-shell AlGaN structure are expected to serve as excellent alternatives for substantially enhancing the efficiency of the next generation of high-efficiency UV LEDs.

Low volume shrinkage, high bio-based, and UV-curable coatings from castor oil-based reactive diluent via a one-step reaction

UV-curing technology possesses the advantages of fast curing, and cured at room temperature, which has been developed rapidly in recent years. However, the volume shrinkage usually occurs during the UV-curing polymerization process, seriously hindering its application. In this paper, a low volume shrinkage, high bio-based contents, and UV-curable resins was fabricated from the raw materials of castor oil, and cardanol. A three functional castor oil-based reactive diluent (COSH) was synthesized using a one-step method of thio-ene click reaction, and the COSH was blended with cardanol-based PUA (CNPUA) oligomer with different content, and prepare bio-based UV-curable materials. The comparative investigation were conducted on the thermal, and mechanical properties with petroleum-based diluents of trimethylolpropane triacrylate (TM), and trimethylolpropane tris (3-mercaptopropionate) (TMSH), respectively. As the content of COSH increased to 40%, the bio-based content of the CNPUA/COSH reached to the highest value of 60.0%, and the viscosity and volume shrinkage of CNPUA/COSH exhibited the lowest data of 1651 mPa·s, and 13.3%, respectively. The COSH not only had good dilution ability, but also possessed excellent anti volume shrinkage ability, and the mechanism of the anti shrinkage COSH was also explored. In addition, the three long carbon chain structures of the COSH endowed the cured coating excellent adhesion of 1 level, and pencil hardness of 3 H-4 H, as well as the flexibility of 2 mm. Lastly, the kinetics of the resulting resins were studied using real-time infrared spectroscopy (RT-IR). This study provides a feasible method for preparation of oil-based reactive diluents, and a new strategy for constructing the sustainable UV-curable materials with high performance.

To Shed Light on the UV Curable Coating Technology: Current State of the Art and Perspectives

The industrial application of UV curable coatings is being widely commercialized at a rapid pace with very diversified product markets. UV curing has existed for many years now, but the new commercial opportunities emerging for sustainable, and climate friendly technologies have driven demand for photo-curable coating systems. It is primarily attributed to its environmentally friendly solvent-free and energy-efficient method. Precedented UV light curable coatings are being commercialized and numerous lamp sources are being extensively studied. In such an era of predominant research evolving the UV curing technology horizon, we attempt to outline the state of the art, opportunities, and challenges. This contribution attempts to highlight, in a comprehensive way, sustainable UV coating on the basis of recent research advancements, existing challenges and prospective scope in this field. With a set of prerequisite foundational knowledge into UV curable coatings and mechanisms, the review has meticulously looked at the recent research advancements. This review contribution attempts to focus on three aspects: the known science behind UV curing coatings, coupled with the recent advancements, and future opportunities.

Preparation and Properties of UV-Curable Waterborne Polyurethane Acrylate/MXene Nanocomposite Films

In this study, waterborne polyurethane acrylate (WPUA)/MXene nanocomposite films with varying MXene loadings were fabricated using UV-curing technology, where MXene (Ti3C2Tx) was employed as a nanofiller. The microstructure and chemical structure of the WPUA/MXene nanocomposite films were examined by XRD and FTIR, respectively. The water contact angle testing demonstrated that the incorporation of MXene into the nanocomposite films led to an increase in their hydrophilic properties. The tensile strength, the elongation at break, and Young’s modulus of the WPUA/MXene nanocomposite coatings exhibited an initial increase followed by a decrease with increasing MXene loadings. Compared to the pure WPUA film, the tensile strength and elongation at break of nanocomposites with 0.077 wt% MXene loading reached their maximum values, which increased by 39.9% and 38.5%, respectively. Furthermore, the glass transition temperature and the thermal stability were both enhanced by MXene to some extent. This study introduces a novel method for utilizing MXene in UV-curable waterborne coatings.

Designing layered V2O3@C with stable oxygen defects via UV-curing technology for high‑performance Zn-ion hybrid supercapacitors

Zn‑ion hybrid supercapacitors (ZHSCs) have attracted enormous interest recently due to the perfect integration of superb energy density and power density. However, they are still bottlenecked by the low specific capacities of inadequate carbon cathodes. Herein, a layered carbon cathode embedded with oxygen-deficient V2O3 (Od-V2O3@C) is prepared via a UV-curving technology, which endows the super uniform anchoring of Od-V2O3 into the carbon matrix. The stabilities of the crystal phase and oxygen vacancies of Od-V2O3 are significantly improved due to the Od-V2O3 being tightly immobilized in the carbon. Density functional theory (DFT) calculations reveal that introduced oxygen defects enhance the electronic conductivity and reduce the adsorption energy of Zn2+, thus increasing the storage performance. The Od-V2O3@C features both reversible faradic reactions and electric double‑layer capacitance, leading to a large capacity of 200.3 mA h g−1 even at 20 A g−1 with a long cycle life (remains 80.6% after 12,000 cycles). Impressively, the ZHSC delivers an exceptional high energy density of 195.0 Wh kg−1 (363.1 W kg−1) and a power density of 13959.4 W kg−1 (162.9 Wh kg−1). This work provides a novel strategy to construct advanced carbon-coated ultra-small metal-oxides compounds, which can be applied to other energy storage fields.

SOx-modified porous carbon as a highly active electrocatalyst for efficient H2O2 generation.

A SOx-decorated porous carbon electrocatalyst that exhibits excellent 2e- oxygen reduction reaction activity is synthesized using UV-curing technology in combination with a pyrolysis process. The H2O2 selectivity using the SOx-porous C shows 95.1% at 0.4 V and delivers a H2O2 production rate of 604.2 mmol gcat-1 h-1. Density-functional theory calculations reveal the reasons for the improvement of catalytic performance.

A solvent-free and scalable method to prepare alkali soluble soybean oil-based epoxy acrylic resin for photoresist application

The raw materials of commercial resin for photoresists nearly all come from petroleum resources. To follow the policy of “green chemistry”, it is urgent to employ renewable, biodegradable, green biomass resources instead of petroleum for the construction of photoresist resin. In this study, the alkaline soluble biobased epoxy acrylic resins are successfully prepared via a ring-opening reaction of epoxidized soybean oil (ESO) with the modified acrylic precursor (MMHEA), followed by diisocyanate modifying to introduce a small amount of polyurethane. The structures of the precursor and product resin are characterized and determined by FT-IR and 1 H NMR analysis. Subsequently, the properties of the resins and the related UV-curable coating films are tested detailedly. The results show that the product resin modified by diisocyanate possesses significantly improved viscosity (higher than 123 Pa s), and the UV-curable coating film containing hexamethylene diisocyanate has a moderate crosslinking density of 1443.18 mol m -3 and the excellent mechanical performances with the tensile strength of 20.40 ± 0.53 MPa, elongation at break of 30.74 ± 1.00% and toughness of 4.44 ± 0.11 MJ m -3 . Moreover, the UV-curable coating films can dissolve completely in 10 wt% NaOH solution at room temperature within 40 min. The prepared product resin is in line with the requirements of photoresist, which can be used in the printed circuit boards. This study develops and provides a solvent-free and one-pot method to prepare biobased epoxy acrylic resins, which are suitable to use as photoresist resin. The use of biomass raw materials and green UV-curing technology follows the principles of green chemistry. And the preparation method of biobased functionalized resins with universal applicability can be easily extended to use in large-scale industrial resin production construction. • A renewable polyfunctional resin was prepared from epoxy soybean oil. • The UV-curable resin with alkali solubility can be used for the photoresist. • Good toughness, thermal stability and crosslinking density properties of resin. • The utilization rate can reach 100% by solvent-free and one-pot method. • The resin can be used in large-scale industrial production applications.

Preparation of siloxymethyl-modified silicone acrylate prepolymers with UV/moisture dual curability for applications in anti-smudge and anti-fingerprint coatings

UV-curing technology is an efficient, energy-saving and eco-friendly technology, which has been widely used in industrial production and daily life. However, UV curing is difficult to achieve with thick coatings, coloured coatings, and shadowed regions of coatings, which greatly limits the applicability of this process. As reported herein, UV/moisture dual curable siloxymethyl-modified silicone acrylate (SMSA) prepolymers were synthesized through the two-step sequential hydrosilylation of pentaerythritol tetraacrylate (PETTA), hydride-terminated polydimethylsiloxane (H-PDMS) and trimethoxysilane (TMOS). The prepolymer contains UV-curable acrylate groups and moisture-curable siloxymethyl groups, and thus it can be readily cured via exposure to UV light, moisture, or a combination of UV light and moisture. Combining the advantages of UV and moisture curing, the prepolymer is capable of curing rapidly and overcomes the problem of UV curing about shadowed areas and thick coatings. This combined UV/moisture dual curing process also solves the problem of oxygen inhibition and poor adhesion of conventional UV-curable silicone materials. The properties of UV/moisture dual cured coatings were characterized and found to exhibit excellent transparency, heat resistance, as well as hydrophobicity. The transparencies of these coatings are over 93% even the thicknesses are up to 100 µm. The coatings remain stable when temperatures reach up to 296.5 and 317.2 °C. The water contact angles of coatings are between 97° and 103°, and surface energies of the coatings vary from 25.43 to 21.27 mN/m. The UV/moisture dual cured coatings also have excellent resistance to smudge and fingerprints. Therefore, they will be suitable for the preparation of anti-smudge and anti-fingerprint coatings.

Usage of UV-Curable Soybean Oil Based Coating Formulations for Pretreated Cotton Fabrics

This study aims to design an alternative way for the laminated fabric manufacturing with a cleaner production method, by using a bio-based coating formulation and time/cost saving, environmentally friendly UV-curing technology, compared to the conventional petroleum based, heat and solvent requiring laminating process. For this purpose, acrylated epoxidized soybean oil oligomer was synthesized and included in coating formulations for the application on cotton fabrics via UV-curing. The obtained oligomer was characterized by FTIR and 1H NMR spectroscopies. In order to enhance the bonding between the fabric and coating layer, fabrics were pretreated by sodium hydroxide, pectinase enzyme, and a commercial washing agent prior to the coating process. The effects of pretreatment methods on the wettability, tensile and peel strength, and abrasion resistance of the fabrics were all examined before/after coating process. Enzyme pretreatment revealed promising results by increasing the surface roughness, fibrillation, and hydrophilicity of the cotton fabrics.

Facile fabrication of biobased porous material via the photocuring technique and a template-assisted approach for oil/water separation

In this study, we developed a facile, low-cost and eco-friendly approach to prepare a sustainable, porous, polymeric sorbent for oil/water separation by using photocurable soybean oil-based urethane methacrylate and inexpensive salt porogen as raw materials. By combining UV curing technology and a salt template-assisted method, a biobased porous sorbent with good hydrophobicity, lipophilicity, and recyclability was prepared. The effects of particle size and content of salt porogen on the density, morphology, porosity and surface wettability of porous sorbent were analyzed and discussed in detail to optimize the preparation conditions. Due to its unique three-dimensional porous structure and large specific surface area, the prepared biobased porous material exhibits the ability of rapid organic solvent absorption and could serve as sorbents that effectively realized the separation of oil/water mixtures. Moreover, all of the key materials are almost low cost and available in large quantities, meaning that this biobased porous material is expected to be used in oil/water separation on a large scale.