Curable Polyurethane Research Articles

Erratum: Effect of Hydrophilic Bentonite as a Filler on Curing Performance of Pigmented UV Curable Polyurethane Acrylate Coating

Erratum: Effect of Hydrophilic Bentonite as a Filler on Curing Performance of Pigmented UV Curable Polyurethane Acrylate Coating

Synthesis and characterization of UV‐curable polyurethane acrylates derived from trimethylolpropane and hydroxyethyl methacrylate: Effect of 2‐hydroxyethyl methacrylate (HEMA) content on thermal stability, gloss properties, and microstructure

Synthesis and characterization of <scp>UV</scp>‐curable polyurethane acrylates derived from trimethylolpropane and hydroxyethyl methacrylate: Effect of 2‐hydroxyethyl methacrylate <scp>(HEMA)</scp> content on thermal stability, gloss properties, and microstructure

Preparation and Application of UV Curable Waterborne Organosilicon Acrylic Polyurethane with Controllable Silicon Content

Preparation and Application of UV Curable Waterborne Organosilicon Acrylic Polyurethane with Controllable Silicon Content

Highly flexible liquid metal/photocurable polymer electrodes via direct laser patterning

A highly flexible electrode was fabricated using eutectic gallium-indium (eGaIn) liquid metal combined with an ultraviolet (UV)-curable polyurethane acrylate (PUA) polymer. The eGaIn liquid metal electrodes prepared by a negative-type direct patterning technique using a UV pulse laser can eliminate the need for complex photolithography masks. The optimal UV pulsed laser peak fluence was ∼1.43 J/cm2 to pattern and sinter the eGaIn/PUA composite electrode simultaneously. The laser-patterned eGaIn/PUA composite electrode under the optimal laser condition exhibited a remarkable electrical conductivity of 6.33 × 105 S/m with a patterning resolution of ∼40 μm. Moreover, the resistance of the electrode only deteriorated by 0.95% after 50,000 cycles of severe cyclic folding at a peak strain of 2.5% with a bending radius of 1 mm, demonstrating its exceptional flexibility and durability. These easily patterned eGaIn flexible electrodes via direct laser patterning techniques hold great promise for applications in wearable and flexible electronic devices that require extreme flexibility.

Encouragement of Graphite and Graphene Oxide Particles on Corrosion Protection Properties for Polyurethane Palm Oil Based UV Curable Coating

This research explores the impact of derivative graphite additives in enhancing the corrosion prevention system of UV curable polyurethane coatings based on palm oil. UV irradiation technique was used in this study to produce cured protection coating. Two types of particles, respectively graphite and graphene oxide were used to understand the differential of both particles in physicomechanical behaviour of the curable coating. The study delves into the formulation and characterization of these coatings, assessing their effectiveness in preventing corrosion. The polymerisation effect by UV irradiation and influence of filler (graphene oxide and graphite) on physical properties of coating were studied by using Fourier Transform Infrared Spectroscopy (FTIR) and gel content together with hardness test. Besides that, X-ray Diffraction (XRD) and Field emission scanning electron microscopy (FESEM) were used to investigate the morphology of curable coating. Meanwhile Electro impedance spectroscopy (EIS) and contact angle measurement were carried out to investigate the related behaviour on corrosion protection properties. All the results were concluded to explain the role of graphite and graphene oxide in curable coating crosslink network. The finding in this study indicates that tortuosity structured which formed by graphite and graphene oxide in UV curable coating matrix were successfully retard corrosion rate per year on mild steel from 31.24 mpy to 43.91 x 10-6 mpy. This work aims to provide valuable insights into the development of eco-friendly and efficient corrosion protection solutions in the realm of coatings and materials science.

Open time studies of cold curing polyurethane adhesives using a standardized spatula test setup suitable for near-production conditions

The presented studies introduce a new set-up and method to analyse the maximum open time of cold curing adhesives in a production environment. By using this new set-up, a manual spatula test, Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) and a rheological method, the curing reaction of two cold curing two component polyurethane adhesives, were investigated. Furthermore, the effect of different joining times on the bonding behaviour were investigated using single lap shear samples.The lap shear tests showed that the prior problem for industrial applications is the dimensional accuracy rather than the adhesion to the substrates as all samples showed cohesive or substrate near cohesive failure even when joined after the maximum open time. All used methods showed a coherent curing behaviour for both adhesives. However, the derived times as well as their accuracies vary depending on the used method. Using the easy manual spatula test, the open time is determined by the sensory feelings of the testing person while pressing a wooden spatula into the adhesive bead and is often used in industrial applications. However, the accuracy lies only within 10–20 s especially for slow curing adhesives. In comparison, the ATR-FTIR method, which is based on the decrease of the isocyanate group during the reaction, showed shorter times, whereas longer times were determined by observing the complex viscosity increase of the rheological measurements. Even though the ATR-FTIR and rheological measurements showed reproducible times due to the required laboratory environment and testing procedure, they are therefore not suitable for production conditions. As the introduced new method is based on the manual spatula test, it is suitable for the production environment with the advantage of a good reproducibility. Furthermore, with this method decreasing maximum open times were observed for increasing bead cross sections.

Facile fabrication of robust and universal UV‐curable polyurethane composite coatings with antibacterial properties

AbstractThe colonization of bacteria and biofilm formation on the surface of medical devices is one of the main causes of nosocomial infections. The development of antimicrobial functional materials with robust and universal properties has been a hot research topic in this field. In this paper, a novel type of polyurethane composite coating was developed by a complementary combination of polyurethane and antibacterial agents. A photocurable anionic waterborne polyurethane was first synthesized using polycarbonate diol (PCDL), isophorone diisocyanate (IPDI), 2,2‐dimethylolpropionic acid (DMPA), and hydroxyethyl acrylate (HEA) as raw materials. Polyurethane composite coatings were prepared by associating cationic antibacterial agents with polyurethane molecules through electrostatic assembly, hydrophobic interactions and hydrogen bonding, and the mechanical properties, adhesion, and antibacterial properties of the polyurethane composite coatings were studied. The results showed that the polyurethane composite coatings had good mechanical properties, and the introduction of cationic antibacterial agents significantly improved the antibacterial ability of the polyurethane material. The antibacterial efficiency of polyurethane against E. coli and S. aureus reached 99% and exhibited durable antibacterial performance as well. Moreover, the polyurethane composite coatings showed excellent adhesion to a variety of substrates, demonstrating their potential application as a universal antimicrobial coating in the medical field.Highlights Construction of polyurethane composite with electrostatic self‐assembly method. Surface coating technology with fast curing, robustness, and universality. Excellent mechanical and antibacterial properties of composite coatings.

Enhanced hydrophobic performance of UV-curable palm oil polyurethane by fluoroacrylate monomer

Driven by the versatility of crosslinked complex network formed by the reaction of double bonds during photopolymerization, ultraviolet (UV) curable palm oil polyurethane (POPU) was modified by the addition of fluoroacrylate monomer to increase its hydrophobicity properties. Fourier transform infrared spectroscopy showed a successful attachment of the fluoro group to POPU. Fluoroacrylate palm oil polyurethane (FPOPU) also showed good hydrophobic properties as FPOPU-6% has the highest contact angle which is 108.22°. In the sliding angle test, FPOPU-2% provided the highest roll-off properties with the lowest angle of incline which was 16.6°. The addition of fluoroacrylate at 6% also lowered the water absorption properties of POPU from 4.94% to 3.98%. To further investigate the cause of hydrophobicity increase, scanning electron microscopy and atomic force microscopy analysis were conducted. The morphology showed fluorine component migration increased the roughness of the coating by the coating’s hydrophobicity performance. Overall, fluoroacrylate monomer addition successfully improved the hydrophobic properties of POPU.

Thermally curable polyurethanes with main-chain benzoxazine and pendant carboxylic acid groups and their use as electrically insulating coatings

Thermally curable polyurethanes with main-chain benzoxazine and pendant carboxylic acid groups and their use as electrically insulating coatings

Synthesis of vanillin-based UV curable polyurethane dispersions for wood coating applications

Synthesis of vanillin-based UV curable polyurethane dispersions for wood coating applications

Facile fabrication of high performance hydrophilic anti-icing polyurethane methacrylate coatings cured via UV irradiation

In this article, high performance hydrophilic anti-icing coatings with carboxyl groups were facilely fabricated via UV curing polyurethane methacrylate prepolymers, which were prepared through polyaddition of isophorone diisocyanate (IPDI), poly(propylene glycol) (PPG), dimethylolpropionic acid (DMPA) and 2-hydroxypropyl methacrylate (HPMA) gradually in acetone (A series prepolymer) or isobornyl acrylate (IBOA) (B series prepolymer), and finally treated with triethylamine (TEA). The structures of A series prepolymer and the corresponding cured coating were confirmed via various techniques. The anti-icing performance of the cured coatings was investigated by ice freezing delay test, ice adhesion strength test, water contact angle and water absorption tests, and DSC test. Based on the testing results, the anti-icing behavior was defined as the incomplete icing of water on hydrophilic surface to weaken the interface adhesion. The ice adhesion strength firstly decreased as the DMPA content increased. At DMPA content of 5 %, the coating displayed a stable and very low ice adhesion strength of 40 kPa even after 25 times of icing (at −12 °C) and de-icing (at 25 °C) cycling. At even higher DMPA content, the ice adhesion strength improved because of the anchoring effect of the ice. Moreover, when IBOA was used as reactive diluent and participated in the polymerization with the prepolymers, the obtained B series coatings could have much improved mechanical properties, together with low ice adhesion strength. The facile fabrication process, excellent anti-icing performance and adjustable mechanical properties should make the coatings suitable for various purposes.

Castor oil‐based UV‐curable polyurethane acrylate resins for digital light processing (DLP) 3D printing technology

AbstractIn this work, a novel UV‐curable polyurethane acrylate (PUA) oligomer was developed from castor oil (CO). Reaction monitoring and structures of the PUA oligomer were characterized by Fourier transform infrared (FTIR) and 1H nuclear magnetic resonance (NMR). Subsequently, a series of UV‐curable resins were prepared by combining PUA with different reactive diluents, and their effect on thermal and mechanical properties was investigated. From the overall characterization trend, it was observed that the formulation containing trimethylolpropane triacrylate (TMPTA) showed the highest mechanical strength and thermal stability. Whereas the formulation containing isobornyl acrylate (IBOA) showed the least performance, and dipropyleneglycol diacrylate (DPGDA) showed properties ranging between TMPTA and IBOA. Furthermore, incorporating 1% TiO2 into the formulation increases the resin's viscosity and mechanical properties without disturbing its thermal stability. This work offered a simple method to prepare vegetable oil‐based high‐performance PUA resins that could be used in the 3D printing industry for general‐purpose prototyping applications to make architectural models, automotive components, and medical components.

Optimizing the Superhydrophobicity of the Composite PDMS/PUA Film Produced by a R2R System

Maintaining the surface of solar cell panels free from contaminants to ensure their efficiency is a time-consuming and tedious task. Therefore, several methods of fabricating artificial transparent superhydrophobic surfaces have been reported to overcome that problem. However, most of the proposed fabrication methods are unscalable due to their complexity. Herein, a facile and cost-effective roll-to-roll system to fabricate a highly flexible and optically transparent polydimethylsiloxane/polyurethane acrylate superhydrophobic (FTPPS) film was proposed. The superhydrophobicity of the film was achieved by the combination of the surface roughness─the ultraviolet curable polyurethane acrylate (PUA) microstructures and the low surface energy material coating─the thin polydimethylsiloxane layer coated on PUA structures using capillary force. The superhydrophobicity of the FTPPS film was carefully optimized using various designs of PUA micro-post and the material properties of the film were examined systematically by different characterization techniques. The highest measured static water contact angle (WCA) of the FTPPS film is 153.3° ± 1.8 and its lowest water sliding angle is ∼9.5° ± 0.2. Moreover, the film still exhibited high WCAs of more than 142° even after being impacted multiple times by an adhesive probe or sand grains. This result demonstrates the high mechanical durability and flexibility of the as-fabricated superhydrophobic film. Finally, the potential application of the film as a protective cover for solar cells was also illustrated through the consistent photovoltaic conversion efficiency of the solar cell module covered by the film compared to that of the uncovered solar panel.

Preparation and Properties of UV and Aziridine Dual–Cured Polyurethane Acrylate Emulsion

For the UV–curable waterborne polyurethane acrylate (WPUA) emulsion, the free carboxylic groups in the molecular chains introduced by hydrophilic monomers are the inherent disadvantage. We prepared UV and aziridine dual–cured WPUA (UV/AZ–WPUA) emulsion that the carboxylic groups can be crosslinked by the trifunctional aziridine crosslinking agent, trimethylolpropane tris(2-methyl-1-aziridinepropionate) (Sac–100). The effects of Sac–100 content on the gel fraction, tensile properties, hardness, wear resistance, water resistance, and surface morphology of the cured films and coatings were investigated. The results show that, with the increase of the Sac–100 content, the gel fraction, tensile strength, elongation at break, and toughness of the films increase first and then decrease and the wear weight loss and water absorption ratio gradually decrease; in addition, Sac–100 also has an effect on the surface roughness of the coatings. Through comprehensive evaluation, it is considered that the optimum Sac–100 content is 4 wt% in UV/AZ–WPUA system. With the optimum Sac–100 content, the gel fraction of the coating film is 89.78 wt%, the tensile strength is 34.58 MPa, the elongation at break is 343.64%, the toughness is 65.08 MJ/m3, the wear loss is 4.7 mg, and the equilibrious water–absorption ratio is 11.63 wt%. Compared with the UV–cured film without Sac–100, the tensile strength, toughness, and hardness of the dual–cured films increase by 155.4%, 129.3%, and 25.7%, respectively, and the water absorption ratio decreases by 27.1%.

Synthesis and characterization of interpenetrating polymer networks (IPNs) based on UV curable resin and blocked isocyanate/polyols

Interpenetrating polymer networks (IPNs) are a non-bonded combination of two or more cross-linked polymers and have superior mechanical properties. Herein we synthesized a series of IPNs by a sequential UV-thermal dual-curing method, which is consisted of UV curable resin network and polyurethanes (PU) network. Blocked isocyanate (BI), polyols, and UV curable resin solutions were mixing completely, the resulting mixture was exposed to UV light to obtain a single network. Then the double network was formed via thermally triggered reaction of deblocking-isocyanate and polyols. The effect of polyol hydroxyl number (from two to six) on properties of IPNs was systematically studied. The results exhibit that pentaerythritol as polyol can be dual-cured by UV and heating to give the highest tensile strength (17.5 MPa), of a 21% increase compared to unheated sample. Furthermore, a series of semi-interpenetrating networks (semi-IPNs) were obtained by using polytetramethylene ether glycol (PTMEG) instead of the polyols. The results showed that introducing interpenetrating or semi-interpenetrating networks exhibit improved mechanical properties of the UV curable resin. Besides, the deblocking temperature of BI is just appropriate for the 3D-printing temperature.

Combustion behavior of end-sealed nitroamine propellant by photocurable composite deterrents

In this work, energetic composite composed of UV curable polyurethane acrylate and RDX was used as deterrent coating for 19-perforated nitroamine propellants plasticized by nitroglycerin and 1, 5-diazido-3-nitrazpentane (DIANP). The nitroamine propellant was end-sealed with the photocurable energetic composite material by using spraying and UV curing method. Combustion behaviors including burning progressivity and temperature sensitivity were studied by performing closed bomb test on propellants with 0.74%, 1.01% and 1.15% deterrent. The inner structure detection revealed that the deterrent penetrated into the perforations during coating process. The end-sealed propellant with blocked perforations exhibited inhibition of initial gas generation rate, which was demonstrated by dynamic vivacity curves. It is inspiring that the propellants coated with 1.01% and 1.15% deterrent presented excellent consistency according to the dynamic vivacity curves between 20 °C and 50 °C. Moreover. it can be indicated that the plugs in perforations conduced to temperature independence property of propellant under ambient temperature. This benefit contributes to improvement of the firing safety at high temperatures.

Synthesis and characterization of bio-based UV curable polyurethane coatings from algal biomass residue

Synthesis and characterization of bio-based UV curable polyurethane coatings from algal biomass residue

Influence of the Reaction Injection Moulding Process on the Thermomechanical Behaviour of Fast Curing Polyurethane

In this contribution, the influence of the reaction injection moulding process on the thermomechanical material behaviour of aliphatic hexamethylene diisocyanate (HDI) based fast curing polyurethane is demonstrated. Uniaxial tensile tests, temperature-frequency dependent dynamic mechanical thermal analysis (DMTA) and Differential Scanning Calorimetry (DSC) are used to show the differences in properties for ten different sets of process parameters. The mould and resin components temperature, the mass flow during the filling process and the residence time during the reaction process of the polyurethane are varied in several stages. Further experiments to determine the molar mass of the molecular chain between two crosslinking points of the polyurethane are used to explain the process influences on the thermomechanical properties. Thus, a direct correlation between manufacturing and material properties is shown. In addition, the mutual effect of the different parameters and their overall influence on the material behaviour is presented.

UV-curable self-matting waterborne polyurethane acrylate coating via self-wrinkled surface during curing in open-air.

This study developed and evaluated a series of ultraviolet (UV) curable self-matting waterborne polyurethane acrylate (UV-WPUA) coatings based on the self-wrinkled surface during UV-curing in the open-air. This method is simple, efficient, eco-friendly, and it does not require complicated or expensive equipment. The FT-IR spectrum indicates that the peaks of C[double bond, length as m-dash]C in UV-WPUA have disappeared after UV irradiation. The gloss value of the UV-WPUA cured film can be affected by the wrinkles on the surface of the film and adjusted it by controlling the content of the photoinitiator in the liquid coating, since the content influences the dimensions of the wrinkles. As the height of the wrinkle increased, the gloss value of the UV-WPUA cured film decreased, and when the incident angles are 20° and 60°, the gloss values are less than 3 GU and 5 GU, respectively. Moreover, the cured film has a maximum water contact angle of 109°, which is affected by wrinkles and positively correlated with the surface roughness of the film. Furthermore, the cured film has excellent properties of thermal stability, tensile strength, pencil hardness, cross-cut adhesion and resistance to abrasion properties, making it well suited for the furniture, leather, and textile applications.

UV curing polyurethane–acrylate composites as full filling thermal interface materials

Thermally enhanced and insulating polyurethane acrylate composites can be used as fully filled TIMs by pre-filling and then UV curing.