UV-curable Waterborne Polyurethane Acrylate Research Articles

Biomimetic high water adhesion superhydrophobic surface via UV nanoimprint lithography

Imitating nature and comprehending its workings is a means for human beings to advance the development of functional materials. In this study, UV nanoimprint lithography technology was utilized to successfully replicate the micro-nano hierarchical structure (micro-papillae and nano-wax tube crystals) present on the surface of the natural fresh lotus leaf. A series of UV-curable waterborne polyurethane acrylate (UV-WPUA) surfaces with special wetting and superhydrophobic properties were obtained. The polydimethylsiloxane negative stamp with lotus leaf’s structure was obtained through a stamp replica molding method, and then the UV-WPUA resin covered with the negative stamp was exposed to 172 nm Xe2* excimer and medium-pressure mercury lamps to mimic the micro-nano hierarchical structure of the lotus leaf. The UV-WPUA surfaces displayed high water adhesion superhydrophobic properties, with a water contact angle reaching 160.8° and water adhesive force of 140.0 μN, and exhibiting excellent self-cleaning performance. The results indicate that higher the UV intensity, the more accurately the surface replicates the micro-nano hierarchical structure of the lotus leaf, resulting in larger water contact angle and higher adhesive force. This study paves the way for the advancement of functional surfaces through the simulation of natural materials.

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%.

A novel UV-curable waterborne polyurethane-acrylate coating based on green polyol from hydroxyl telechelic natural rubber

A novel UV-curable waterborne polyurethane-acrylate (WPUA) was firstly prepared based on hydroxyl telechelic natural rubber (HTNR) via sequential emulsion polymerization. The WPUA was composed of HTNR, Hexamethylene diisocyanate (HDI), 2-hydroxyethyl acrylate (HEA), and the content of hydroxymethyl propionic acid (DMPA) was studied for effects on particle size, stability, and morphology of the new series of WPUA dispersions. The WPUA had a good stability at a total solids content of about 20%. Particle size and dispersion stability slightly decreased with DMPA content. The WPUA gave a good film formation and can provide good wettability with high surface free energy. The mechanical and thermal properties of WPUA film were improved by UV-curing. The effects of photoinitiator (Darocur1173) content were investigated. The UV-cured WPUA films showed better mechanical properties and less water absorption than the not cured WPUA film. Also, the surface wetting was the improvement in the water resistance of the coating on the substrate. In addition, the thermal properties by TGA and the dynamic properties by DMTA slightly increased with photoinitiator dose level due to the higher crosslink density and decreasing the molecular weight between crosslink (Mc) caused the Tg shift to a higher temperature.

Synthesis and characterization of UV-curable waterborne Polyurethane–acrylate modified with hydroxyl-terminated polydimethylsiloxane: UV-cured film with excellent water resistance

In this paper, a series of UV-curable waterborne polyurethane–acrylate (WPUA) emulsions were synthesized by using isophorone diisocyanate (IPDI) as the hard segment, polybutylene adipate glycol (PBAG) and different dosages of hydroxyl-terminated polydimethylsiloxane (HTPDMS) as the soft segment, 2,2-dimethylolpropionic acid (DMPA) as hydrophilic chain extender, and pentaerythritol triacrylate (PETA) as the blocking agents. The properties of the WPUA emulsions were then characterized by using Fourier transform infrared spectrometry, Zeta potential analysis, dynamic light scattering, and UV-cured films were characterized through Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, scanning electron microscope, UV–vis spectrophotometer, and thermogravimetric analysis, as well as by measuring the contact angle of water, testing the water absorption. The results indicated that with increasing HTPDMS content in the WPUA, the particle size of the emulsion was increased significantly, while the absolute value of Zeta potential was increased slightly. The resistance of WPUA cured film to water was increased. The ultimate water absorption declined from 11.12 % to 6.81 % and the equilibrium time of water absorption extended from 50 h to more than 100 h. When the HTPDMS content of WPUA was 10.0 wt%, the water contact angle of the cured film was the largest at 114°, which indicated that the surface of the cured film has been changed from a hydrophilic surface to a hydrophobic one. Thermogravimetric analysis results showed that the initial decomposition temperature of WPUA film gradually increased with adding of HTPDMS, performing better thermal stability.

UV LED curable epoxy soybean-oil-based waterborne PUA resin for wood coatings

An environmentally friendly waterborne wood coating with a rapid curing speed and good mechanical properties was investigated. Acrylated epoxidized soybean oil (AESO) and pentaerythritol triacrylate (PETA) were introduced to a UV-curable waterborne polyurethane acrylate (PUA) resin, which realize the fast curing of the coating under a 395-nm UV LED light source. The emulsion and film were characterized by particle size, FTIR, 1H-NMR and the mechanical properties. The result showed that the mechanical properties of the film were optimal with AESO content 45%, which tensile strength, elongation at break and modulus of elasticity were 27.53 MPa, 26.35%, and 293.62 MPa, respectively. The particle size of the emulsion was smaller than 50 nm. It displayed a good stability and a uniform distribution. The glass transition temperature was 123.3 °C. The hardness, the adhesion force, the water absorption rate, the gloss and the abrasion loss were 6H, Level 1, 9.9%, 22.1°, and 0.002 g, respectively. After pre-drying and UV LED irradiation, the wood coating cured quickly in a short time. The epoxy soybean-oil-based waterborne PUA resin indicated highly promising in the field of wood coatings.

Research on the Performance of Series Waterborne Polyurethane Acrylate Modified Epoxy Acrylates

In this study, a series of bifunctional-based UV curable waterborne polyurethane acrylate modified epoxy acrylate (UV-WPUA) was prepared by using 2,4-toluene diisocyanate (TDI), Epoxy resin (E51) and polyethylene glycol (PEG) as the main materials. Waterborne resin and UV curing film with content of C-O-C were obtained by using polyethylene glycols with different molecular weights. The infrared spectra (FT-IR) demonstrated the presence of C=C and epoxy bond in the UV curing film chains. In addition, the molecular weight of the oligomer, and glass transition temperature, gelation rate and thermogravimetric analysis of the films were investigated.

Synthesis, mechanical properties and iron surface conservation behavior of UV-curable waterborne polyurethane-acrylate coating modified with inorganic carbonate

The performances of UV-curable waterborne polyurethane-acrylate (WPUA) composite modified with nano calcium carbonate (NCA) were highlighted in this work. The γ-methacryloxy propyl trimethoxyl silane (KH-570) and polysorbate 80 (Tween-80) were used to enhance interfacial interaction between NCA and WPUA matrix. Transmission electron microscopy (TEM), particle size analysis and Fourier transfer infrared (FT-IR) spectrometry were employed to examine the micromorphology and the variation of function group of modified nano calcium carbonate (MNCA). Three different WPUA oligomers were investigated to obtain the optimized R value (the molar ratio of –NCO:–OH) via in situ polymerization and anion self-emulsification process. Results showed that WPUA displayed excellent film-forming ability and mechanical properties when R value was 2.2:1.0. These UV-curable WPUA films modified with MNCA (UV-MNCA/WPUA) were prepared through environmentally friendly UV-curable technology and investigated by thermogravimetric (TG) analysis, scanning electron microscope (SEM), X-ray diffractometer (XRD) and FT-IR. UV-MNCA/WPUA-3-3 film had the best overall performances with MNCA-2 and UV-WPUA at the mass ratio of 3.6%. Finally, the experimental results demonstrated that the as-obtained UV-curable coating had outstanding conservation effect to iron surface, providing a promising way for protection of iron cultural relics.

Preparation and properties of UV‐curable waterborne polyurethane–acrylate emulsion

ABSTRACTPolyurethane–acrylate oligomer terminated with multiple unsaturated bonds was prepared using isophorone diisocyanate, (IPDI), methylene diphenyl diisocyanate, and polyols as monomers, using 2,2‐dimethylol propionic acid as hydrophilic chain extender, together with pentaerythritol triacrylate (PETA) as end‐capper. The UV‐curable waterborne polyurethane–acrylate (UV‐WPUA) composite emulsion was obtained by mixing the PUA oligomer with certain content of reactive diluents and then dispersing the mixture in water. The molecular structure of the polyurethane prepolymer, PUA oligomer, and UV‐cured polymer was investigated by Fourier transform infrared spectroscopy. The influence of the composition and content of the diluents and end‐capper on UV‐WPUA properties, including the emulsion stability, thermal property, water resistance, adhesion, hardness, glossiness of polymer film were studied. The results show that the WPUA emulsion has excellent stability, and the UV‐cured film features good hardness and remarkable water resistance when PETA is used as end‐capper and the end‐capping ratio of the polyurethane prepolymer is 70% and dipentaerythritol hexaacylate/dipropylene glycol diacrylate (mass ratio 1:1) is used as diluent. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45208.

Photoinitiability of triblock copolymer PDMS-b-(PMAEBB-co-PDMAEMA)2 as a macro-photoinitiator prepared via RAFT polymerization

In this study, we prepared a novel triblock copolymer, PDMS-b-(PMAEBB-co-PDMAEMA)2 (tri-PI) bearing side-chain benzophenone (BP) and coinitiator amine, as a macro-photoinitiator via reversible addition-fragmentation chain transfer (RAFT) copolymerization of the polymerizable photoinitiator 2-(methacryloyloxy)ethyl-2-benzoylbenzoate (MAEBB) and the unsaturated coinitiator amine 2-(dimethylamino)ethyl methacrylate (DMAEMA) with a bifunctional polydimethylsiloxane (PDMS) macro-chain transfer agent (macro-CTA). The structure of synthesized copolymer was confirmed by Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR), differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). The effects of the photoinitiator/coinitiator ratio, concentration, and photoinitiator systems on the photopolymerization kinetics of tri(propylene glycol) diacrylate (TPGDA) were investigated by real-time FT-IR. The mobility of the tri-PI chain segments was proven by X-ray photoelectron spectroscopy (XPS), and the surface morphology of TPGDA curing coatings was studied by scanning electron microscopy (SEM). Results showed that tri-PI strongly suppressed the effect of oxygen inhibition on the photopolymerization system. Tri-PI was also used in the curing of UV-curable waterborne polyurethane acrylate (UV-WPUA) resin to determine its versatility.

The utilization of carbon nitride to reinforce the mechanical and thermal properties of UV-curable waterborne polyurethane acrylate coatings

Abstract The waterborne polyurethane-acrylate (WPUA and Wsi-PUA) oligomers were prepared by anionic self-emulsifying method, using isophorone diisocyanate (IPDI), polyethylene glycol (PEG), dimethylol propionic acid (DMPA), vinyl hydroxyl silicone oil (VHSO) and hydroxyethyl methyl acrylate (HEMA) as raw materials. Then, a series of UV-curable waterborne Wsi-PUA–C 3 N 4 composites containing different content of g-C 3 N 4 were obtained with oligomer and photoinitiator Darocur 1173. FTIR, XRD, TEM, SEM, and TGA were employed to investigate the structure, morphology and thermal property of the Wsi-PUA–C 3 N 4 composite films. The effect of g-C 3 N 4 content on the performance was also investigated. The mechanical performance, water resistance and gel content of UV-PUA films were measured. It was found that with g-C 3 N 4 particle was introduced into Wsi-PUA oligomer, the hardness, tensile strength, gel content, water resistance and thermal stability of composite films were significantly augmented. Moreover, when the content of g-C 3 N 4 was 1.0 wt.%, the UV-curable film had the best mechanical property. The obtained composite is promising for a number of applications, e.g., for protecting the surfaces of metal and wood.

Preparation and properties of castor oil/pentaerythritol triacrylate-based UV curable waterborne polyurethane acrylate

Abstract Castor oil (CO)/pentaerythritol triacrylate (PETA)-based UV curable waterborne polyurethane acrylate (UV-WPUA) was prepared by using isophorone diisocyanate (IPDI), poly(caprolactone diol) (PCL) and dimethylolbutyric acid (DMBA) as the main materials. A series of emulsions and films with different content of CO were obtained. The infrared spectra, together with the nuclear magnetic resonance spectroscopy, demonstrated the presence of CO and PETA in the UV-WPUA chains. The surface roughness of the curing film was measured by atomic force microscope. In addition, the effects of CO content on particle size, thermal properties, glass transition temperature and tensile performance of the emulsions and films were investigated. With the content of CO increasing from 1.72 to 8.58 wt%, the particle size of the UV-WPUA emulsion increased and the particle size distribution gradually widened. The appearance of the emulsions transformed from blue transparent into opaque and the stability decreased gradually. Water resistance, glass transition temperature for soft segment and thermal performance of the films were improved. The tensile strength of the films firstly increased and then decreased.

The effect of PETA/PETTA composite system on the performance of UV curable waterborne polyurethane acrylate

ABSTRACTUV curable waterborne polyurethane acrylate based on pentaerythritol triacrylate (PETA)/pentaerythritol tetraacrylate (PETTA) composite system was prepared by using polycaprolactone glycol (PCL), isophorone diisocyanate (IPDI), β‐cyclodextrin (β‐CD) and 2,2‐dimethylol butanoic acid (DMBA) as the main materials. Besides, PETA was used as capping agent and PETTA was used as reactive diluent. By varying the additive amount of PETA and PETTA, a series of emulsions and films were obtained. The molecular structure was characterized by infrared spectra and a series of performance tests such as particle size, contact angle, tensile properties, UV curing performance, differential scanning calorimetry and thermogravimetric analysis were conducted. The result showed that more compact network structure was formed by introducing PETTA with higher reactivity into the polyurethane molecule under UV irradiation and many performances were improved as a whole. However, there existed phase separation to a certain extent. Especially when the content of PETTA was higher than 83.33%, the effect of compatibility became more prominent. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41262.

Preparation, characterization and properties of UV-curable waterborne polyurethane acrylate/SiO2 coating

The UV-curable waterborne polyurethane acrylate (UV-WPUA) oligomer was first prepared based on isophorone diisocyanate (IPDI), polyether polyol (NJ-220), dimethylol propionic acid (DMPA), and hydroxyethyl methyl acrylate (HEMA) via an in situ method. With the different content tetraethoxysilane (TEOS) and 3-glycidyloxypropyltrimethoxysilane (GLYMO) as coupling agents, a series of waterborne UV-WPUA/SiO2 oligomers were prepared by the sol–gel process. The physical and mechanical properties of the UV-WPUA and UV-WPUA/SiO2 hybrid coating materials were measured. The UV-WPUA and WPUA/SiO2 hybrid materials were characterized using FTIR spectra, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD) measuring apparatuses to determine their structures, thermal properties, surface morphologies, etc. The results showed the SiO2 particles of the hybrid materials had wide dispersion, forming a good interfacial bonding layer on surfaces. The tensile strength, water resistance, and thermal properties of the hybrid materials were better than those of the UV-WPUA. The resulting UV-WPUA/SiO2 hybrids are promising for a number of applications, e.g., for high-performance water-based UV-curable coatings.

Synthesis and characterization of UV-curable waterborne polyurethane acrylate possessing perfluorooctanoate side-chains

The dispersion of UV-curable waterborne polyurethane acrylate possessing perfluorooctanoate side-chains (FPUA) terminated with pentaerythritol triacrylate (PETA) was synthesized by incorporating fluorine groups into the side chains of the polyurethane macromolecular from condensation polymerization by using perfluorooctanoate glycerate (OF-diols) as chain extender, while the polyurethane macromolecular was synthesized from isophoronediisocyanate (IPDI), dimethylol propionic acid (DMPA), and poly (propylene glycol) (PPG) etc. The chain extender was prepared from 2,2-dimethyl-1,3-dioxolane-4-methyl perfluorooctanoate (OF-diols-pg) by acid hydrolysis with trifluoroacetic acid. The structure of FPUA was characterized by FTIR, NMR, elemental analysis, UV–vis and Mass spectra, and the properties of the synthesized FPUA emulsion were also discussed. The effect of fluorine content on the UV-curing dynamics was studied and the UV-curing speed decreased with increment in fluorine content. Contact angle measurements shown that the hydrophobic property of the surface greatly increased by incorporation of fluorine into the polyurethane chain. In addition, scanning electron spectroscopy (SEM) analysis was applied to characterize the morphology of the fracture surface of the UV-cured FPUA which became phase-mixed after annealing.

UV-curable waterborne polyurethane-acrylate: preparation, characterization and properties

The waterborne polyurethane-acrylate (PUA) oligomer was firstly prepared based on isophorone diisocyanate (IPDI), polyether polyol (NJ-210), dimethylol propionic acid (DMPA) and hydroxyethyl methyl acrylate (HEMA) via in situ and anionic self-emulsifying method. The UV-curable polyurethane-acrylate (UV-PUA) was obtained with oligomer, monomers (BA and TPGDA) and photoinitiator Darocur 1173. FT-IR, DSC and TGA were employed to investigate the structures and thermal properties of the UV-PUA films. The effects of BA/TPGDA ( R) value, the content of Darocur 1173 and the UV curing time on the performances were investigated. Some mechanical performances, solvent resistance and the gel content of UV-PUA films were measured. When the ratio of BA/TPGDA was 5/5, the UV-PUA film had the best solvent (water, alkali and ethanol) resistances. Besides, with the ratio of the BA/TPGDA increasing, the surface drying time increased. When the content of Darocur 1173 was 4%, the gel content achieved the maximum while the surface drying time achieved the minimum. The obtained UV-curable polyurethane-acrylates are promising as oligomers for UV-curable coatings, plastics, inks and adhesives.

UV-curable waterborne polyurethane acrylate modified with octavinyl POSS for weatherable coating applications

UV-curable waterborne polyurethane acrylate (WPUA) modified with octavinyl polyhedral oligomeric silsesquioxane (OVPOSS) was prepared via photopolymerization between OVPOSS and WPUA. Structural and morphological features of WPUA/OVPOSS coatings were assessed using Fourier transform infrared spectroscopy, transmission electron microscopy and X-ray diffraction. Thermal properties of the WPUA/OVPOSS hybride coatings have been improved over the pure waterborne polyurethane acrylate analyzed by thermal gravimetric analysis. Performance of the coatings was also evaluated using water absorption, hardness, contact angle, X-ray photoelectron spectroscopy (XPS). The data showed that the WPUA/OVPOSS coatings possessed better water resistance and thermal oxidative stability in comparison with pure WPUA.

Effect of average functionality on properties of UV-curable waterborne polyurethane-acrylate

A series of ultraviolet (UV) curable waterborne polyurethane-acrylate (WPUA) with different average functionalities were synthesized in new methods. The chemical structures of WPUA were confirmed by Fourier-transform infrared spectroscopy (FT-IR) and the effect of average functionality on properties of WPUA was systemically investigated. It was found that the average functionality had a positive effect on the water resistance and tensile strength of WPUA, to make optimal formation of WPUA molecule chains available, whereas the increasing of average functionality decreased the viscosity and extension of WPUA samples. Besides, through the investigation on the UV curing kinetics, it was found that the average functionality too high or too low was unfavorable for the increase of unsaturation conversion. The morphology and microstructure of WPUA films were also comprehensively discussed with WAXD patterns and fractured surface observed from SEM images.

UV curable waterborne polyurethane acrylate dispersions based on hyperbranched aliphatic polyester: effect of molecular structure on physical and thermal properties

AbstractA novel waterborne hyperbranched polyurethane acrylate for aqueous dispersions (WHPUDs) based on hydroxy‐functionalized hyperbranched aliphatic polyester Boltorn™ H20 was investigated. The effects of structural composition and crosslinking density have been studied in terms of swellability by water, thermal degradation, viscosity changes as well as transmission electron microscopy (TEM) morphology. The swell ratio showed an increasing trend with the higher concentration of ionic group, which is due to the increased total surface area of particles. The results of thermogravimetric analysis (TGA) for cured WHPUD films indicated good thermal stability with no appreciable weight loss until 200°C. The activation energies were evaluated and were found in the range 154–186 kJ mol−1. It was observed that an increase in hard segment content provoked the increases in thermal degradation temperature and activation energy of waterborne dispersions. The transmission electron photographs revealed that the average particle sizes of aqueous dispersions were in the range 30–125 nm. Owing to the enlargement of the stabilization site, the particle size decreased as the content of carboxyl group and degree of neutralization increased. The viscosity of WHPUDs increased rapidly with increasing the degree of neutralization. Moreover, water showed a favorable viscosity reduction effect. Copyright © 2004 John Wiley & Sons, Ltd.