Polyurethane Acrylate Research Articles

Poisson Effect‐Assisted Replication Lithography for Rapid Fabrication of Three‐Dimensional Microstructures

Demands for micro‐ and nano‐fabrication techniques have been increasing over recent decades due to their foundational importance in fields such as electronics, sensors, displays, biotechnologies, and energy technologies. Still, the rapid and efficient fabrication of complex 3D microstructures has long been a challenge due to the inherent limitations of conventional imprint lithography and the slow fabrication speed of maskless lithography systems using femtosecond lasers. This study introduces a novel lithographic replication method for the rapid replication of intricate 3D microstructures with closed‐loops by leveraging the Poisson effect‐driven lateral deformation of soft molds. Specifically, the suggested technique employs an elastomeric soft mold, engraved with negative cavity parts of the target structure separated by intentional gaps. Lateral deformation of the material allows the separated cavities to assemble for replication of target microstructure and defectless release from the soft mold. In addition to the experimental demonstrations of the proposed method using well‐known materials like polydimethysliloxane (PDMS) for the soft mold and UV‐curable polyurethane acrylate (PUA) for replication, essential considerations such as material selection and master mold design are discussed. The presented method not only broadens the capabilities of imprint lithographic techniques but also holds promise for the large scale, continuous fabrication of complex 3D microstructures.

Synthesis and properties of waterborne polyurethane acrylate emulsions with high bio‐based content

AbstractThe bio‐based hydrophilic monoglycerol succinate was synthesized and reacted with bio‐based raw materials including polyols, pentamethylene diisocyanate, 1,4‐butanediol, to prepare the waterborne polyurethane acrylate (Bio‐WPUA) emulsions with high bio‐based content. The effect of bio‐based polyol categories including poly(trimethylene ether glycol), poly(tetrahydrofuran), and castor oil on the properties of Bio‐WPUA and its films were studied. The structure, thermal stability, crystallinity, contact angle, and mechanical properties of Bio‐WPUA film were characterized with fourier infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, X‐ray diffraction, contact angle analyzer, and mechanical tensile testing. It was found that Bio‐WPUA film containing poly(trimethylene ether glycol) as the soft‐segmented display good tensile stress, thermal stability, and water resistance with 1.38% of the water absorption rate, while Bio‐WPUA containing castor oil polyol as the soft‐segmented had good tensile strain and low‐temperature film‐forming properties with excellent film properties. The bio‐carbon content of Bio‐WPUA was high up to 40% according to ASTM D6866‐22, and possesses good physical mechanical and chemical resistance performance. The results provide theoretical guidance for the synthesis of polyurethane emulsions with bio‐based materials instead of petroleum‐based materials.

No‐organic solvent, no‐fluorinated waterborne superhydrophobic coatings based on SiO2 and IBTS

AbstractWaterborne superhydrophobic coatings have attracted widespread attention. However, organic solvents, fluorine‐containing compounds, and complex operational technologies hinder superhydrophobic coatings development severely. Herein, A simple method of preparing water‐based superhydrophobic coatings by one‐step spraying without organic solvent and fluorine is reported. The particles of silicon dioxide (SiO2) was modified by isobutyltriethoxysilane (IBTS), then combined with waterborne acrylic polyurethane (WPUA) and phenolic resin (PF), baked at 110°C to fabricate superhydrophobic coatings. According to the contact Angle (CA), hardness, adhesion, and other parameters, the ratio of SiO2 and PF of the composite coatings was optimized. Results showed that the superhydrophobicity and physical properties of the coating are the most exceptional at the content of SiO2 is 0.6 g, and the PF is 25%. In addition, related experimental results show that the coatings have good water resistance and self‐cleaning ability, the special nano/micro structure of the coatings also endows it excellent abrasion resistance. Exceptional hydrophobicity and physical properties meeting the actual application conditions of superhydrophobic coatings. Therefore, the simple method for preparing superhydrophobic coatings has great application prospects.

Thiol‐Ene Photo Crosslinked PUA‐PUMA‐Based Flexible Gel Polymer Electrolyte for Lithium‐Ion Batteries

AbstractCrosslinked polymer films, formed via sol–gel and UV photocrosslinking, serve as gel polymer electrolytes (GPEs) in lithium‐ion batteries. Combining polyurethane acrylate (PUA), polyurethane methacrylate (PUMA), pentaerythritol tetrakis (3‐mercaptopropionate) (PETMP), and 3‐mercaptopropyl trimetoxysilane (MPTMS) yields flexible membranes, enhancing stability and liquid electrolyte compatibility. The resulting GPE displays higher ionic conductivity (1.46 × 10−3 S cm−1) than Celgrad2500, with PUA‐PUMA's hydrophilicity and PETMP's SH groups preventing leakage. GPPF1, the developed GPE, offers improved ionic conductivity, a stable electrochemical window up to 3.8 V, and heightened safety for versatile energy storage systems.

A Novel Polyfunctional Polyurethane Acrylate Derived from Castor Oil-Based Polyols for Waterborne UV-Curable Coating Application.

Because of its unique molecular structure and renewable properties, vegetable oil has gradually become the focus of researchers. In this work, castor oil was first transformed into a castor oil-based triacrylate structure (MACOG) using two steps of chemical modification, then it was prepared into castor oil-based waterborne polyurethane acrylate emulsion, and finally, a series of coating materials were prepared under UV curing. The results showed that with the increase in MACOG content, the glass transition temperature of the sample was increased from 20.3 °C to 46.6 °C, and the water contact angle of its surface was increased from 73.85 °C to 90.57 °C. In addition, the thermal decomposition temperature, mechanical strength, and water resistance of the samples were also greatly improved. This study not only provides a new idea for the preparation of waterborne polyurethane coatings with excellent comprehensive properties but also expands the application of biomass material castor oil in the field of coating.

High-Performance Dental Resins Containing a Starburst Monomer

Dimethacrylate-based chemistries feature extensively as resin monomers in dental resin–based materials due to their distinguished overall performance. However, challenges endure, encompassing inadequate mechanical attributes, volumetric shrinkage, and estrogenicity. Herein, we first synthesized a novel resin monomer, 9-armed starburst polyurethane acrylate (NPUA), via the grafting-onto approach. Compared to the primary commercial dental monomer 2,2-bis [p-(2′-hydroxy-3′-methacryloxypropoxy) phenyl] propane (Bis-GMA) (with a viscosity of 1,174 ± 3 Pa·s and volumetric shrinkage of 4.7% ± 0.1%), the NPUA monomer achieves the lower viscosity (158 ± 1 Pa·s), volumetric shrinkage (2.5% ± 0.1%), and cytotoxicity (P < 0.05). The NPUA-based resins exhibit the higher flexural strength, flexural modulus, hardness, and hydrophobicity and lower volumetric shrinkage, water absorption, and solubility compared to the Bis-GMA (70 wt%)/TEGDMA (30 wt%) resins. The NPUA-based composites exhibit significantly higher flexural strength, flexural modulus, and hardness and lower volumetric shrinkage (171.4 ± 3.0 MPa, 12.6 ± 0.5 GPa, 2.0 ± 0.2 GPa, and 3.4% ± 0.2%, respectively) compared to the Bis-GMA group (120.3 ± 4.7 MPa, 9.4 ± 0.7 GPa, 1.5 ± 0.1 GPa, and 4.7% ± 0.2%, respectively; P < 0.05). This work presents a viable avenue for augmenting the physicochemical attributes of dental resins.

Synthesis and characterization of ureidopyrimidinone-functionalized polyurethane acrylates and their hybrid nanocomposites for UV coating applications

In this study, ureidopyrimidinone moieties (UPy), capable of physical crosslinking via quadruple hydrogen bonding, were successfully incorporated into UV-curable polyurethane acrylate prepolymers. First, a hydroxyl-terminated unsaturated ester monomer was synthesized and reacted with isophorone diisocyanate to create a hydroxyl-terminated UV-curable urethane oligomer (U–OH). Then, isocyanate-terminated building blocks (UPy moieties and an acrylate-based photosensitive monomer) were synthesized and used in various ratios to functionalize U–OH for the preparation of a series of UV-curable UPy-containing polyurethane acrylate (PUA) resins. The resulting products were structurally characterized using 1H NMR and FTIR spectroscopy. Furthermore, organic–inorganic hybrid nanocomposites were obtained by introducing silane coupling agents into PUA resins using the sol–gel process. A series of UV-curable UPy-containing PUA coatings and hybrid nanocomposites were prepared, and their synergistic effect on coating properties was investigated. The dynamic mechanical analysis revealed that the Tg of the samples increased with increasing UPy content, although the mechanical properties remained largely unaltered, as shown by the stress–strain test. The studies also demonstrated that the hybrid nanocomposites exhibited higher decomposition temperatures and better thermal stability compared to pure PUAs. All the coatings exhibited good transparency in the visible region. An optical microscope was used to investigate the self-healing property by scratching the plexiglass panels with a razor blade. Among the other samples, the coating with the highest percentage of UPy content exhibited the best self-healing ability after heat treatment at 90 °C for 10 min.Graphical abstract

Biomimetic design of micro- and nano-wrinkle wood surface via coating reinforced with hyperbranched polymer grafted cellulose nanofibers for skin-tactile performance

Inspired from human skin, micro- and nano-wrinkled wood surface with skin-tactile performance was designed and developed using a waterborne UV-curable polyurethane acrylate coating and cellulose nofibers (CNF). To further improve the properties, the CNF was diacetylated to D-CNF and further grafted with a hyperbranched polymer containing rich end amino groups (HB-CNF). The surface structure and chemical reactions were characterized, and the skin-tactile performance of the coating was comprehensively investigated. The HB-CNF exhibited excellent dispersion in the coating, and extensive reactions occurred between the two through the –NH2 and terminal –NCO groups, resulting in much improved mechanical properties and durability. Micro-wrinkles with a width of approximately 12–15 μm and a height of 8–14 μm were created, and nano-protrusions of wrinkles ranging from to 50–100 nm were obtained. The coated surface was hydrophobic and exhibited high resilience after compression, with a gloss of 3.3 GU at an incident angle of 60° and a static friction coefficient of 0.26, both of which were similar to those of human skin. The results presented an effective strategy for high-performance wood products with a good feeling, which is helpful to improve the market competitiveness and meet the people's pursuit of a better life.

Digital light 3D printing of artificial bone with star-shaped polycaprolactone-based polyurethane acrylate

Advanced medical materials and manufacturing technologies are highly in demand in artificial bones. Herein, a four-arm star-shaped polycaprolactone polyurethane acrylate (FPCLA) was designed and synthesized. The photosensitive character of FPCLA contributed to the rapid prototyping and personalized customization under digital light processing (DLP) 3D printing technology. The FPCLA was prepared by introducing unsaturated double bonds into polycaprolactone tetraethyl alcohol (PCLT). We characterized the physico-chemical properties of the material through FTIR, H-NMR, GPC, DSC and SEM. Cell behaviors on material were observed in vitro. In addition, we employed a DLP 3D printer to evaluate the feasibility of FPCLA to fabricate artificial bone model. The photocuring star polycaprolactone was confirmed in detail by detection method. SEM analyses demonstrated that FPCLA has good tenacity. The material can be used to fabricated artificial bone with a diameter of 3.02 mm at its narrowest by DLP 3D printing technology. The cell survival rates of CCK-8 and Live/Dead fluorescence staining experiments were both above 90%, which indicated safety and feasibility of such new-generation artificial bone made of synthetic polymers.

Adamantane-based low-dielectric-constant photocurable resin for 3D printing electronics

In this work, a novel formulation is developed to prepare photocurable polyurethane acrylate (PUA) resin with a low dielectric constant for 3D printing applications. To amend the deficient electronic properties of regular 3D printed PUA materials, a symmetric polymer structure 1,3-adamantanediol (ADO) is introduced into the PUA polymer matrix to effectively decrease the dielectric constant. A low dielectric constant (Dk = 2.26) and a low loss tangent (Df = 0.018) at 10 GHz after formulation, are significantly lower than commercial PCB materials (High Tg FR-4, Dk = 4 and Df = 0.02). The modified PUA also exhibits great mechanical properties (tensile strength 12.02 MPa and elongation break at 111.35%) and can be further metalized with adhesive copper layers (5B adhesion test). With little addition of BN powder (1 wt%), the Df of PUA resin can also be effectively reduced (Df = 0.006), and the measured values of its metalized substrate antenna parameters are proven to be within the acceptable range for 5 G devices. The PUA resin can also be printed into complex 3D structures for 5 G flexible circuit board applications with good design flexibility, and the low dielectric constant provides the opportunity to replace traditional rigid FR-4 substrates for 5 G flexible board applications.

UV-curable organic silicone grafting modified waterborne polyurethane acrylate: Preparation and properties

The organosilicon grafting copolymerization waterborne polyurethane acrylate composite coating (WPUA@KH570) with high surface properties was prepared by the UV curing method from mixing silicone monomer surface-modified ZnO (Si@ZnO) as photoinitiator to waterborne polyurethane acrylate (WPUA) emulsion. The effects of the polyurethane isocyanate index (R), the addition amount of hydrophilic chain elongator DMBA (wDMBA), the ratio of PU/PA on the stability of the synthesized WPUA emulsion were explored. The properties of the WPUA@KH570 composite coatings with different contents of organosilicon surface-modified ZnO were characterized by the particle size distribution meter, FTIR, XRD, SEM, UV–Vis–NIR spectrophotometer, contact angle (CA) and water absorption rate (WAR). The results showed that when R = 1.4, wDMBA = 0.04 and PU/PA = 0.6, the WPUA emulsion had an excellent stability. When the content of organosilicon modified ZnO reached 1.5 wt%, the CA increased to 90.6°, the WAR decreased to 15.4 %, and the absorbance reached 0.5. The WPUA@KH570 composite coating could be changed from hydrophilic to hydrophobic, which can step further promoted the surface properties, water resistance and UV absorption.

Acrylate composite polyurethane binder for steel bridge deck pavements: Process optimization by response surface methodology and microanalysis

AbstractTo better serve the steel bridge deck paving project, a novel room‐temperature curing acrylate composite polyurethane binder (APUB) was developed as a substitute for traditional asphalt binders. APUB was synthesized by the copolymerization of a custom‐made polyurethane prepolymer (BDO‐PU) and acrylate. Fourier transformed infrared and proton nuclear magnetic resonance spectroscopy analyses confirmed the presence of carbamate structures in prepolymer BDO‐PU. Utilizing tensile strength, breaking elongation and water absorption as optimization criteria, the response surface methodology was used to optimize synthesis process of APUB. The results showed that the optimized parameters for APUB synthesis include an isocyanate index (R) of 1.5, a mass ratio of methyl methacrylate to BDO‐PU of 1.1, and a curing agent content of 2.7%. These settings resulted in predicted values of 10.12 MPa for tensile strength, 123.85% for breaking elongation, and 0.075% for water absorption. Experimental validation demonstrated the consistency between the predicted and actual properties of APUB. Further microanalyses, including dynamic mechanical thermal analysis, differential scanning calorimetry, and scanning electron microscope, confirmed APUB exhibits excellent component compatibility and glass transition temperatures suitable for bridge engineering environments. Overall, APUB demonstrates outstanding tensile properties, water resistance, low energy consumption, and potential applications in the steel bridge deck pavement industry.

Water‐based UV curable hybrid urethane‐acrylates formed by acid–base interaction between tertiary amine containing polyurethane and acrylic acid for photocoating and ink applications

AbstractUrethane acrylate hybrids are commonly used in polyurethane dispersions (PUD). PUDs are key ingredients in UV curing applications and UV curing is widely used in coatings and inks. The preparation of PUDs involves many volatiles in the form of solvents and reagents that are also carried over in the UV curing step. This article reports a process, which totally eliminates these volatile components and additionally introduces many flexibilities. The process involves acid–base interaction between tertiary amine containing polyurethane and acidic vinyl monomer like acrylic acid forming polyurethane‐acrylate (PU‐AA) hybrids in water. The developed process also overcomes the prepolymer and “endcapping” approaches used in the preparation of PUDs that restrict the molecular weight of polyurethanes. Simultaneously, because of the prevalence of large number of vinyl components in the polymer backbone through the acid–base interaction, it functions as a multifunctional acrylate similar to the reactive diluents used in UV curing applications. Thus, it helps to increase the cross‐linking density of the UV cured substrates. In general, high crosslinking density helps to improve characteristics like hardness, scratch, solvent and stain resistance of coated substrates. The process has been demonstrated to form transparent and opaque coated substrates and cured inks. This development potentially helps to shift the process from an industrial activity to do‐it‐yourself domain and has implications for the development of components for 3D printing sustainably.

Adhesive-free PDMS/PUA bilayer using selective photopolymerization for transparent, attachable, and wearable triboelectric nanogenerator

Polydimethylsiloxane (PDMS) is a widely used elastomer substrate in various fields, including wearable devices, because of its diverse advantages. However, PDMS has low stretchability and lack of adhesion, thus requires additive adhesives, such as conventional tapes, which have potential to cause skin trauma. Meanwhile, polyurethane acrylate (PUA) is also a broadly used elastomer given its various advantages, such as biocompatibility and mechanical properties. This study introduces, for the first time, a novel laser process method to form an adhesive-free PDMS/PUA bilayer film. By adjusting UV laser scanning parameters, the interfacial bonding between the PDMS and PUA can be improved without additional additives. The fabricated PDMS/PUA bilayer showed high transparency, improved mechanical properties, and adhesiveness properties. Combining with PUA (as a backbone and adhesive layer) and PDMS (as a triboelectric layer), the PDMS/PUA bilayer was further used to fabricate a transparent, attachable, and stretchable PDMS/PUA-based triboelectric nanogenerator (PP-TENG) device. The transparent attachable PP-TENG successfully detected minute human motions and functioned as a virtual piano keyboard and a virtual computer keyboard when attached to an arbitrary paper.

Composite aerogel incorporating low temperature phase change microcapsules for enhanced thermal insulation

Cryogenic transportation and storage confront significant challenges from harsh weather conditions, heightened energy consumption, and epidemic situations, compelling the need for the creation of exceptionally efficient thermal insulation materials. To address this demand, a composite phase change aerogel was designed in this study through incorporating low-temperature microencapsulated phase change microcapsules (MPCM) into a cellulose nanofiber/polyvinyl alcohol (CNF/PVA) system. The MPCM, consisting of a polyurethane-acrylate (PUA) shell and an n-tetradecane core, exhibited excellent encapsulation performance with leak-proof capability. Remarkable low-temperature phase change energy storage properties were observed, including a phase change temperature of approximately 6 °C and an impressive phase change enthalpy of 112 J/g. The MPCM also demonstrated stability during successive heating–cooling repetitions, maintaining its heat storage capacity and morphology for at least 300 cycles. These exceptional thermal characteristics endowed the resulting aerogel with effective thermal insulation and temperature retardation abilities. Meanwhile, the integration of CNF/PVA as the matrix in the composite aerogel led to minimal degradation of thermal storage performance compared to pure MPCM. Moreover, the addition of MPCM significantly enhanced the compressive strength, reaching 5.6 times that of the neat CNF/PVA aerogel. The composite aerogel showed a notably low density of 0.165 g/cm3 and could be reshaped through heating. This work provides a simple yet effective idea for designing bulk materials with low-temperature phase change capabilities, offering promising prospects in the field of thermal insulation.

Fabrication of photocurable liquid-like easy-cleaning coatings based on a polydimethylsiloxane-modified silicone resin

Smooth liquid-like surfaces formed by flexible polymer brushes or alkyl monolayers exhibit great potential as easy-cleaning coatings. However, solvent-free, and easily curable coating formulations that are environmentally-friendly, omniphobic, low-cost, and durable liquid-like surfaces are still lacking. This paper reports the synthesis of a polydimethylsiloxane (PDMS) modified silicone resin additive for the preparation of easy-cleaning photocurable liquid-like coatings. A highly-branched silicone resin (MAP) containing PDMS and acrylate groups was synthesized by acid hydrolysis condensation and then added to polyurethane acrylate (PUA) to prepare UV-curable coatings. The coatings with only 1 wt% MAP addition exhibited hydrophobicity and oleophobicity, as well as dust and graffiti resistance due to their low surface tension and the self-migration of PDMS chains in the MAP resin. Meanwhile, the coating surface was smooth, highly transparent, and showed excellent abrasion resistance because the highly-branched structure of MAP was conjugated with many acrylate groups. This enhanced the compatibility of the MAP resin with PUA and strengthened the cross-link density of the coating. Consequently, the photocurable easy-cleaning coating provides a facile strategy for preparing environmentally friendly and mechanically robust anti-smudge coatings.

Flexible and transparent nanohole-patterned films with antibacterial properties against Staphylococcus aureus.

In this paper, we explore the development of a multi-functional surface designed to tackle the challenges posed by Staphylococcus aureus (S. aureus), a common opportunistic pathogen. Infections caused by S. aureus during surgical procedures highlight the need for effective strategies to inhibit its adhesion, growth, and colonization, particularly on the surfaces of invasive medical devices. Until now, most existing research has focused on nanopillar structures (positive topographies). Uniform nanopillar arrays have been shown to control bacterial behavior based on the spacing between nanopillars. However, nanopillar structures are susceptible to external friction, impact, and force, making it challenging to maintain their antibacterial properties. Therefore, in this study, we investigate the antibacterial behavior of nanohole structures, which offer relatively superior mechanical robustness compared to nanopillars. Moreover, for applications in medical devices such as laparoscopes, there is a pressing need for surfaces that are not only transparent and flexible (or curved) but are also equipped with antibacterial properties. Our study introduces a scalable multi-functional surface that synergistically combines antibacterial and anti-fog properties. This is achieved by fabricating thin films with variously sized holes (ranging from 0.3 μm to 4 μm) using polyurethane acrylate (PUA). We assessed the activity of S. aureus on these surfaces and found that a 1 μm-diameter-hole pattern significantly reduced the presence of live S. aureus, without any detection of dead S. aureus. This bacteriostatic effect is attributed to the restricted proliferation due to the confined area provided by the hole pattern. However, the persistence of some live S. aureus on the surface necessitates further measures to minimize bacterial adhesion and enhance antibacterial effectiveness. To address this challenge, we coated the zwitterionic polymer 2-methacryloyloxyethyl phosphorylcholine (MPC) onto the nanohole pattern surface to reduce S. aureus adhesion. Moreover, in long-term experiments on surfaces, the MPC-coated effectively inhibited the colonization of S. aureus (18 h; 82%, 7 days; 83%, and 14 days; 68% antibacterial rate). By integrating PUA, MPC, and nanohole architectures into a single, flexible platform, we achieved a multi-functional surface catering to transparency, anti-fogging, and anti-biofouling requirements. This innovative approach marks a significant advancement in surface engineering, offering a versatile solution applicable in various fields, particularly in preventing S. aureus contamination in invasive medical devices like laparoscopes. The resultant surface, characterized by its transparency, flexibility, and antibacterial functionality, stands out as a promising candidate for mitigating S. aureus-related risks in medical applications.

Analyze the shaping characteristics of micro-cylindrical-post in manufacturing process of a superhydrophobicity film

Superhydrophobic films (SHF) have recently increased in routine due to their non-wettable capacity. Superhydrophobicity can be occurred by making a micro-structural-post on materials with the surface having a low energy level. Thus, the shaping characteristics of the micro-structural-post should be considered. This paper analyzes the influence and evaluates the characteristics of micro-cylindrical-post having different parameters to the superhydrophobicity of PUA film. Firstly, the structure and characteristics of Polyurethane Acrylate (PUA) material are introduced. Moreover, the manufacturing process to create the micro-cylindrical-post on PUA film is illustrated. Finally, the influence of the different shaping parameters of micro-cylindrical-post on the superhydrophobicity of PUA film is evaluated and analyzed.

A photocurable polyurethane elastomer for digital light processing with comprehensive reusability based on dynamic hindered urea bonds

Digital Light Processing (DLP) 3D printing has emerged as a highly promising technique, enabling the fabrication of intricate geometric structures with ease and precision, without the need for complex mold-making processes. However, the printed objects are typically crosslinked photopolymers that cannot be reshaped, reprocessed and recycled. Herein, we successfully synthesize a dynamic soft polymer crosslinker containing hindered urea bonds (HUBs) composed of polyurethane acrylate prepolymer and tri-functional for recyclable DLP 3D printing. Contributing to the dynamic thermal response of HUBs, the printed objects can be recycled in the initial printing inks at 80 °C in 2h and the obtained recycled ink can be reprinted by DLP achieving a low viscosity and high printing resolution. In addition, the printed objects can be reprocessed by hot-press at 110 °C for 30 min upon a pressure of 5 MPa. By a reasonable proportion of monomer and crosslinker, a series of photocured elastomers were successfully prepared, in which mechanical properties could be tailored by changing the content of the crosslinker. The resulting products exhibited some fascinating attributes, such as excellent fatigue resistance, thermodynamic stability, and transparency. Significantly, the resin can regain initial 3D printing capability after undergoing solvent recycling, which maintains its printing resolution and excellent mechanical properties. This innovative design strategy not only alleviates environmental impact but also plays a pivotal role in developing the DLP 3D printing industry by tackling the long-standing issue of resin recyclability.

The novel preparation of waterborne acrylic polyurethane-silica organic-inorganic interpenetrating network coatings

In this paper, a waterborne acrylic polyurethane-silica organic-inorganic interpenetrating network (IPN-WAPU-nSiO2) coating was prepared using filling hydroxyethylation modified nano-silica with 10 nm diameter (HEM-nSiO2) into waterborne acrylic polyurethane paint. Fourier transform infrared spectroscopy (FT-IR) confirms that HEM-nSiO2 can react with isocyanate to form amino ester bonds, which enhances the compatibility with acrylic polyurethane matrix and the microstructural morphology demonstrates that nano sized silicon are completely integrated into the IPN-WAPU-nSiO2 coating, which forms a significant difference from the composite waterborne acrylic polyurethane-silica (c-WAPU/nSiO2) coating prepared from filling 10 nm diameter of silica. The resulting IPN-WAPU-HEM-nSiO2 coating filling 0.1 wt% of HEM-nSiO2 has outstanding wear resistance, toughness and excellent resistance to salt spray for over 360 h with 15 μm thickness. Tafel curve and electrochemical impedance spectroscopy (EIS) reveal the outstanding corrosion protection: the |Z|0.01Hz of IPN-WAPU-HEM-nSiO2 (3wt‰) coating remains 4.61 × 109 Ω·cm2 after soaking in 3.5 wt% NaCl solution in 60 °C for 60 days, which is caused by the very dense coating with unique organic-inorganic IPN structure.