Preparation and properties of UV‐curable fluorinated polyurethane acrylates

A series of UV‐curable polyurethane acrylates (PUA0, FPUA3, FPUA6, FPUA 9 FPUA12, FPUA15, where the numbers indicate the wt % of perfluoroalkyl acrylate), were prepared from a reactive oligomer [4,4 ?‐dicyclohexymethanediisocyanate(H12MDI)/ poly(tetramethylene glycol)(PTMG)/2‐hydroxyethyl methacrylate (HEMA): 2/1/2 molar ratio, prepolymer:40 wt %] and diluents [methyl methacrylate (MMA, 20 wt %)/ isobornyl acrylate (IBOA, 40–25 wt %)/heptadecafluorodecyl methacrylate (PFA, 0–15 wt), total diluents: 60 wt %]. This study examined the effect of PFA/IBOA weight ratio on the properties of the UV‐curable polyurethane acrylates for antifouling coating materials. The as‐prepared UV‐curable coating material containing a 15 wt % PFA content in diluents (MMA/IBOA/PFA) form a heterogeneous mixture, indicating that a PFA content of approximately 15 wt % was beyond the limit of the dilution capacity of diluents for the oligomer. In the wavelength range of 400–800 nm, the UV‐cured PUA0 film sample was quite transparent (transmittance%: near 100%). On the other hand, the transmittance% of the FPUA film sample decreased markedly with increasing PFA content. XPS showed that the film‐air surface of the UV‐cured polyurethane acrylate film had a higher fluorine content than the film‐glass dish interface. As the PFA content increased from 0 to 12 wt %, the surface tension of the UV‐cured urethane acrylates decreased from 26.8 to 15.6 mN/m, whereas the water/methylene iodide contact angles of the film–air surface increased from 90.1/63.6° to 120.9/87.1°. These results suggest that the UV‐curable polyurethane acrylates containing a PFA content up to 12 wt % have strong potential as fouling‐release coating materials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40603.     

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

Polyurethane–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.     

Synthesis of waterborne polyurethane containing alkoxysilane side groups: Study on spacer linkages

Environmentally friendly waterborne polyurethanes (WPUs) modified by moisture‐curable alkoxysilane have been much studied nowadays. In this work, a new diol‐bearing pendant urea‐propyl trimethoxysilane (APD‐Si) was synthesized and used as the chain extender in the preparation of a silicone‐modified WPU dispersion. Both the formation of hybrid networks based on the condensation of trimethoxysilane groups and the enhanced microphase separation of the hard and soft segments have been found to rely on the strong hydrogen‐bonding capability of the urea‐containing spacers, which link the alkoxysilane groups with the backbone of WPU. Because of the synergism of chemically bonded silsesquioxane and physically hydrogen bonded hard domains serving as crosslinking points, the mechanical properties of the hybrid films of WPU are improved, especially the modulus and yield strength. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46628.     

Preparation and properties of UV‐curable fluorinated polyurethane acrylates containing crosslinkable vinyl methacrylate for antifouling coatings

To obtain highly effective antifouling coatings, a series of UV‐curable polyurethane acrylates containing diluents [heptadecafluorodecyl methacrylate (PFA, 6 wt %)/isobornyl acrylate (IBOA, 34 wt %)/methyl methacrylate (MMA, 20‐5 wt %)/vinyl methacrylate (VMA, 0–15 wt %)] were prepared. This study examined the effect of bulky MMA (20‐5 wt %)/crosslinkable VMA (0–15 wt %) weight ratio on the properties of the UV‐curable polyurethane acrylates. The fluorine concentration in UV‐cured film surface increased with increasing VMA content up to 9 wt % and then decreased. The T_gα, transparency, elasticity, and mechanical properties of the UV‐cured film samples increased with increasing VMA content. The water/methylene iodide contact angles and surface tension of samples increased from 107/79 to 121/91° and decreased from 17.8 to 12.7 mN/m with increasing VMA content up to 9 wt % and then decreased/increased, respectively. From these results, it was found that the optimum VMA content was 9 wt % to obtain a high‐performance antifouling coating. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42168.     

Surface and bulk properties of waterborne polyurethane modified with fluorinated siloxane

Two series of polyester and polyether waterborne polyurethanes (WPUs) modified with poly[(3,3,3‐trifluoropropyl)methylsiloxane] (PTFPMS) were synthesized by prepolymerization method and the effect of PTFPMS on surface and bulk properties were investigated by a variety of experimental methods. FTIR and DSC results showed that the polyester WPU has better compatibility between soft segments and hard segments than polyether WPU in bulk and the degree of phase separation increased in polyester WPU but decreased in polyether WPU with increasing PTFPMS. ARXPS analysis revealed the migration of PTFPMS to WPU surface and the migration ability of Si element was better than F element. AFM images demonstrated that the surface of WPU films became rougher as PTFPMS content increased. The enrichment of PTFPMS with low surface energy and roughened surface imparted good hydrophobicity and oleophobicity to WPU films and polyether WPU has better surface properties compared with polyester WPU. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46473.     

Effects of preparation method on microstructure and properties of UV‐curable nanocomposite coatings containing silica

UV‐curable nanocomposites were prepared by the blending method or the in situ method with nanosilica obtained from a sol–gel process. The microstructure and properties of the nanocomposite coatings were investigated using ²⁹Si‐NMR cross‐polarization/magic‐angle spinning, transmission electron microscopy (TEM), Fourier transform IR (FTIR), differential scanning calorimetry (DSC), and UV–visible (UV–vis) spectra, respectively. The NMR and TEM showed that during the blending method, tetraethyl orthosilicate (TEOS) completely hydrolyzed to form nanosilica particles, which were evenly dispersed in the polymer matrix. However, for the in situ method, TEOS partially hydrolyzed to form some kind of microstructure and morphology of inorganic phases intertwisted with organic molecules. FTIR analysis indicated that the nanocomposites prepared from the in situ method had much higher curing rates than those from the blending method. DSC and UV–vis measurements showed that the blending method caused higher glass‐transition temperatures and UV absorbance than the in situ method. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1119–1124, 2005     

Chain‐extended polyurethane–acrylate ionomer for UV‐curable waterborne coatings

Conventional and chain‐extended UV‐curable waterborne polyurethane–acrylate (PUA) ionomers were prepared from diisocyanate, polyethylene glycol (PEG), dimethylolpropionic acid, and hydroxyethyl methacrylate, and identified with FTIR spectra and 500‐MHz ¹H‐NMR spectra. The number‐average molecular weight (M_n) and polydispersity of chain‐extended PUA were determined by gel permeation chromatography. For the synthesis of chain‐extended PUA, water was employed as the chain extender. The two kinds of PUA prepolymer could be easily dispersed in water in the form of self‐emulsified latex after the carboxyl group attaching to the backbone of PUA was neutralized with tertiary amine. The effects of M_n of PEG, carboxyl content, and type of diisocyanate on the interfacial tension and rheological behavior of PUA dispersions were investigated. The chain‐extended PUA prepolymer could photopolymerize to a greater extent than the conventional PUA, as indicated by differential photocalorimetry. The photopolymerization kinetics of chain‐extended PUA, based on different substrates, were also investigated. The differential scanning calorimetry analysis for the photo‐cured films from PUA dispersions suggested that lower M_n of PEG tended to favor phase mixing between soft and hard segment phases, and higher M_n of PEG would provoke phase separation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1818–1831, 2002; DOI 10.1002/app.10384     

Preparation,mechanical properties of waterborne polyurethane and crosslinked polyurethane‐acrylate composite

The waterborne polyurethane (PU) prepolymer was first prepared based on isophorone diisocyanate, polyether polyol (NJ‐210), dimethylol propionic acid (DMPA), and hydroxyethyl methyl acrylate via in situ method. The crosslinked waterborne polyurethane‐acrylate (PUA) dispersions were prepared with the different functional crosslinkers. The chemical structures, optical transparency, and thermal properties of PU and PUA were confirmed by Fourier transform infrared spectrometry, ultraviolet–visible spectrophotometry, and differential scanning calorimetry. Some physical properties of the aqueous dispersions such as viscosity, particle size, and surface tension were measured. Some mechanical performances and solvent resistance of PUA films were systemically investigated. The experimental results showed that the particle sizes of the crosslinked PUA aqueous dispersions were larger than the PU and increased from 57.3 to 254.4 nm. When the ratios of BA/St, BA/TPGDA, and BA/TMPTA were 70/30, PUA films exhibited excellent comprehensive mechanical properties. The tensile strength and elongation at break of the film were 2.17 MPa and 197.19%. When the ratio of BA/St was 30/70, the film had excellent water resistance and was only 6.47%. The obtained PUA composites have great potential application such as coatings, leather finishing, adhesives, sealants, plastic coatings, and wood finishes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Processing‐structure‐property relationship in rigid polyurethane foams

Rigid polyurethane (PU) foam is used as a thermal insulating and supporting material in domestic refrigerator/freezers and it is produced by reaction injection molding (RIM) process. There is a need to improve the thermal property of rigid PU foam but this is still a challenging problem. Accordingly, this work investigates the RIM process parameters to evaluate their effects on rigid PU foam's structure and hence property. It has been found that mold temperature is a key parameter whereas curing time has negligible effect on structure of PU foam. Cell size, strut thickness, and foam density have been found very critical in controlling the thermal and mechanical properties. Upper and lower values of 30 to 32 kg/m³ density are critical to observe contribution of radiation and solid conductivity separately. Finally, PU foam with 160 µm average cell size, 16 µm strut thickness, below 10% open cell content, and 30 to 32 kg/m³ density allow obtaining better thermal insulation without significant reducing in the compressive strength. The presented work provides a better understanding of processing‐structure‐property relationship to gain knowledge on producing high‐quality rigid PU foams with improved properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44870.     

梳型UV固化水性聚氨酯树脂的制备与表征

通过引入含双键基团的中间体制备了分子链侧基、端基均含可UV固化基团的梳型水性聚氨酯树脂。采1用红外光谱仪FTIR、核磁共振仪H NMR、热重分析仪TGA等分析手段对样品的结构与性能进行了表征。分析表明,所得产品符合预期分子结构的设计,为半透明泛蓝光乳液,粒径细微均匀;固化层呈现2个快速失重温度区间。中间体的加入增强了固化层的耐溶剂性和硬度,附着力、拉伸强度和交联密度也得到提高。()()()     

High‐performance waterborne coatings based on epoxy‐acrylic‐graft‐copolymer‐modified polyurethane dispersions

Polyurethane dispersions (PUDs) have been an active area of research since the early 1940s because of legislative restrictions on the use of organic solvents in conventional solvent‐based products and also because PUDs exhibit almost the same high performance levels as solvent‐borne polyurethanes. In the present study, properties of conventional waterborne PUDs are modified with epoxy‐acrylic graft copolymer blocks. The epoxy‐acrylic graft copolymers were first modified with ethylene diamine to give amine‐terminated blocks which in turn reacted with isocyanate‐terminated prepolymer (prepolymer mixing process) to give modified PUDs. Several experimental sets were prepared with varying compositions. The experimental sets were also prepared using conventional poly(ethylene glycol) blocks and ethylene diamine chain‐extenders. The physico‐chemical properties and film characteristics of the experimental sets show the dramatic improvement in important mechanical properties of PUDs due to grafting with epoxy‐acrylic copolymer blocks. Copyright © 2004 Society of Chemical Industry     

Preparation and characterization of UV‐curable MPS‐modified silica nanocomposite coats

A series of UV‐curable nanocomposites were prepared with 3‐(trimethoxysilyl) propyl methacrylate (MPS) modified nanosilica under the initiation of 2,2‐dimethoxy‐1,2‐diphenylethan‐1‐one. It was found that MPS‐modified nanosilica together with free MPS could form transparent nanocomposite coats. As the particle size of nanosilica increased, the photopolymerization rate, final double bond conversion, and tack‐free time of nanocomposites increased while the surface roughness, glass‐transition temperature, and UV absorbance of nanocomposites decreased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2274–2281, 2005     

Preparation and characterization of hybrid thiol‐ene/epoxy UV–thermal dual‐cured systems

Hybrid thiol‐ene/epoxy coatings were prepared by combining thiol‐ene photo‐curable formulations with epoxy monomers, through a dual UV–thermal curing process. An increase in glass transition temperature and in storage modulus was observed for the hybrid thiol‐ene/epoxy coatings when compared with the pristine thiol‐ene UV‐cured system. Also, the bisphenol A moieties introduced into the hybrid networks during the dual‐curing process induced an increase in thermal stability of the cured materials. It has been demonstrated that the addition of epoxy monomer to the thiol‐ene photo‐curable system is a good strategy to follow in order to improve the final properties of thiol‐ene‐based coatings leading to a wide range of possible applications for the hybrid materials. Copyright © 2010 Society of Chemical Industry     

Preparation of multifunctional thiol‐ and acrylate‐terminated polyurethane: A comparative study on their properties in UV curable coatings

The multifunctional thiol‐ and acrylate‐terminated polyurethane (PU) has been successfully prepared for using as the main resin in the UV curable coatings. The structure and molecule weight of prepared PUs were analyzed by fourier transformed infrared spectroscopy (FTIR) and gel permeation chromatography, respectively. The results showed that the different terminal multifunctional groups have been grafted onto the PU and their difference in molecule weight was significant. Used as the main resin in coatings, the curing kinetic and percentage conversion of the different UV curing coatings system were investigated by real‐time FTIR method, and the effects of terminal functional groups and photoinitiator on the final conversion percentage and conversion rate were also compared. It is observed that the thiol‐terminated PU had higher conversion speed and final conversion percentage due to the remarkable effect of mercapto groups on reducing oxygen inhibition during UV curing process. The shrinkage, viscosity, and adhesion of UV curable coatings with thiol‐ and acrylate‐terminated PUs were also investigated and compared, and the results indicated that the former exhibited lower shrinkage and higher adhesion performances than the latter, along with the lower viscosity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40740.     

Development of acrylated soybean oil‐based UV‐curable coatings with high impact strength from low viscosity oligomer

In recent years, more and more attention has been paid to bio‐based materials due to their sustainability and environmental friendliness. The combination of biomass and ultraviolet (UV) curing technology can reduce the dependence on petroleum products and emissions of volatile organic compounds. In this article, a new environment‐friendly UV‐curable coating with good performances was successfully prepared from acrylated soybean oil (ACSO). ACSO was obtained at low temperature without catalyst and inhibitor by reacting soybean oil‐based polyol with acryloyl chloride and characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance. It was found that the UV‐curable oligomer of ACSO had lower viscosity and better ductility, compared to acrylated epoxidized soybean oil (AESO). The properties of UV‐cured films prepared by ACSO were studied and compared with films from AESO. The results showed that the ACSO‐based films were significantly improved in the adhesion and impact resistance. Furthermore, the addition of styrene could enhance the hardness and impact resistance of films. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45698.     

Acrylic-ester-polyol based novel two-component polyurethane clear coat: Evaluation of performance characteristics

In the current study, a combination of acrylic polyol (AP) and ester polyol (EP) were synthesized and reacted at variable ratios with hexamethylene diisocyanates and isophorone diisocyanates to prepare a transparent two-component polyurethane (PU) coating formulation. The formations of the polyol system, isocyanate system, and the PU systems were confirmed by ¹H nuclear magnetic resonance and Fourier-transform infrared spectroscopy. Transparency of the coatings was examined using haze, and gloss measurement, which showed acrylic-ester-polyurethane (aePU-5 and aePU-6) have 91.5% and 91.8% transparency and gloss of 90.3 and 90.7 GU respectively. The thermal properties like T_g and the thermal stability of the coatings were verified using differential scanning calorimetry, and thermogravimetric analysis respectively which was found to increase with increasing EP content and decreasing AP content which may be ascribed to improved compatibility of copolymers, and homogeneity in PU along with enhanced crosslinking density. The degree of adhesion of coating with the substrate was validated from lap-shear, and cross-cut tape test which showed improved performance at AP:EP ratio of 60:40. The coatings were found to exhibit resistance toward pencil hardness with aePU-5 and aePU-6 having the optimum resistance of 9H. The surface morphology and topography were observed under scanning electron microscopy, and atomic force microscopy, respectively. The outcome confirms the higher smoothness of the surfaces subjected to the increase in EP content. The PU system with 40 wt% AP content and 60 wt% EP designated as aePU-5 was found to exhibit optimum performance.     

Preparation and property of waterborne UV‐curable chain‐extended polyurethane surface sizing agent: Strengthening and waterproofing mechanism for cellulose fiber paper

Waterborne UV‐curable polyurethane (UWPU) dispersions with different hydrophilicity and functionalities were prepared by varying the content of dimethylol butanoic acid (DMBA) and pentaerythritol triacrylate (PETA). And linear and cyclic chain extenders with different functionalities were also incorporated into the UWPU backbone, including isophorone diamine (IPDA), diethylene triamine (DETA), and ethylene diamine (EDA). Effects of DMBA content, PETA content, photoinitiator content, UV curing time, chain extender on the properties of UWPU dispersions and films, as well as the properties of the unsized and sized paper were investigated. The water resistance and mechanical properties of sized paper were greatly relied on the particle size, the molecular weight, the croslinking density, and penetrability of UWPU. UWPU dispersion chain extended with IPDA (IPDA‐UWPU) displayed smaller particle size than that of UWPU. The paper sized with IPDA‐UWPU was endowed with best water resistance, tensile strength, folding strength and surface strength. XPS depth analysis revealed that IPDA‐UWPU exhibited better penetrability into the paper substrate than UWPU. SEM and AFM demonstrated that the smoothness of sized paper was improved, and the bond strength between fibers was enhanced. The obtained UWPU could be directly used as an effective and fast drying surface sizing agent for cellulose fiber paper. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42354.     

Behavior of UV‐cured print inks on LDPE and PBAT/TPS blend substrates during curing,postcuring, and accelerated degradation

During radiation curing, a reactive formulation is converted into a highly crosslinked coating film by means of polymerization reactions. This three‐dimensional (3D) network is resistant to external degrading factors as it cannot be undone by any physical–chemical means. In this study, various ultraviolet (UV)‐curable ink formulations with different pigments were developed. The behavior of the UV‐curable inks was evaluated during UV curing in a photocalorimeter or in a UV tunnel. Inks were exposed to accelerated aging in an accelerated weathering chamber and their physical–chemical properties were investigated. The presence of residual fractions of unreacted species trapped in the 3D network formed during UV curing interferes with the degradation of the main structure during exposure in the weathering chamber. The ink formulations that did not easily absorb UV light increased in gloss and hardness, indicating that residual crosslinking is taking place at the same time that degradation is occurring. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41116.     

Characterization of UV‐curable reactive diluent containing quaternary ammonium salts for antistatic coating

Reactive diluent with quaternary ammonium salts (RDQ) for UV‐curable antistatic coating was synthesized by reacting glycidyl methacrylate (GMA) and piperazin with dropping the methansulfonic acid. In order to compare the curing behavior of RDQ with commercial monomers, the photopolymerization of RDQ, 1,6‐hexandiol diacrylate (HDDA) and 1,6‐hexandiol dimethacrylate (HDDMA) were studied by using real‐time IR spectroscopy. Surface properties such as surface resistance, pencil hardness, and solvent resistance of the cured films containing RDQ were investigated. When used as a reactive diluent in the UV‐curable coating formulation, the RDQ imparted excellent antistatic properties to the final material. The results of an Fourier transform infrared/attenuated total reflectance (FTIR/ATR) depth profile analysis show that RDQ molecules are more concentrated near the surface within a micrometer‐thick layer, indicating that existence of the ionic components in the surface layer is responsible for antistatic property. Film cured from the formulation containing 12 wt % of RDQ showed the best mechanical properties with reasonable surface properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 132–137, 2002; DOI 10.1002/app.10273     

Preparation and evaluation of epoxy methacrylate UV‐curable coatings containing phthalazinone

Epoxy methacrylate resin (EMA) UV‐curable coatings exhibit high reactivity, low viscosity and excellent chemical resistance in environmentally friendly coatings. A novel EMA containing phthalazinone moieties for high temperature resistant UV‐curable coatings was synthesized. The formulations were cured with hexanediol diacrylate (HDDA) and trimethylol propane triacrylate (TMPTA) as reactive diluents promoted by a photoinitiator, and then interpenetrating polymer networks were generated. The mechanical, chemical and thermal properties of the clear coatings were characterized using Chinese National Standard methods (GB). EMA was used with UV radiation curing in combination with 6.7 wt% of HDDA and 13.4 wt% of TMPTA, and the properties of the cured films were as follows: pencil hardness of 5 H, 30% NaOH resistance for 30 days, 15% HCl resistance for 10 days, 3% NaCl resistance for 30 days and 5% weight loss temperature of 300.5 °C. EMA UV‐curable coatings containing phthalazinone exhibit excellent chemical and thermal stability, and could be potential candidates for UV‐curable zero volatile organic compound coatings applied in the fields of salt spray corrosion, strong radiation and high‐temperature resistance. Copyright © 2009 Society of Chemical Industry