UV‐curable,oxetane‐toughened epoxy‐siloxane coatings for marine fouling‐release coating applications

BACKGROUND: UV‐curable coatings are promising candidates for environmentally friendly marine fouling‐release coatings. Cationic UV‐curable epoxy‐siloxane release coatings show good release performance but suffer from poor coating mechanical properties. A difunctional oxetane monomer, DOX, was co‐photopolymerized with an epoxy‐siloxane oligomer at loading levels from 10 to 40 wt% to obtain toughened fouling‐release coatings. RESULTS: The DOX‐toughened coatings showed enhanced cationic photopolymerization activity, solvent resistance and modulus. DOX‐toughened coatings (10 and 20 wt%) exhibited higher impact resistance. The DOX‐toughened coatings showed no leachate toxicity and the coatings were hydrophobic and non‐toxic to biofilm growth when analyzed with marine bacteria and algae. In general, 10 and 20 wt% DOX‐toughened coatings exhibited better marine bacteria and algae fouling‐release performance among the DOX‐toughened coatings. Pseudo‐barnacle shear release stress for the DOX‐toughened coatings increased with increasing DOX content. Live barnacle reattachment assay showed that 10 and 20 wt% DOX‐toughened coatings had comparable barnacle removal stress to commercial silicone reference coatings. CONCLUSIONS: DOX‐toughened (10 and 20 wt%) UV‐curable epoxy‐siloxane coatings exhibited enhanced mechanical properties and better overall marine fouling‐release performance among the toughened UV‐curable release coatings studied. Copyright © 2008 Society of Chemical Industry     

Preparation and performance on polycarbonate of B/F/Si‐containing hybrid coatings

A series of UV‐curable B/F/Si‐containing hybrid coatings was prepared by the anhydrous sol‐gel technique. The chemical structure of the coatings was characterized by FTIR, RTIR, and ¹HNMR techniques. The UV‐curable coatings were applied to polycarbonate substrates. The physical and mechanical properties of the UV‐cured coatings, such as pendulum hardness, pencil hardness, contact angle, gel content, MEK rubbing test values, tensile strength, abrasion resistance, and gloss, were examined. Thermal gravimetric analysis (TGA) was done. The relative flammability of the hybrid coatings was tested by the limiting oxygen index (LOI) method. Results of all analyses conducted on the free films and coatings are discussed. J. VINYL ADDIT. TECHNOL., 19:39–46, 2013. © 2013 Society of Plastics Engineers     

Effects of small molecular weight silicon‐containing acrylate on kinetics,morphologies, and properties of free‐radical/cationic hybrid UV‐cured coatings

A series of UV‐curable, silicon‐containing mixtures were prepared by adding different micro amounts of small molecular weight silicon‐containing acrylate KH570 to an interpenetrating polymer network system composed of cycloaliphatic polyurethane acrylate, trimethylolpropane triacrylate, cycloaliphatic epoxy resin, free‐radical photoinitiator Irgacure 754 and cationic photoinitiator Irgacure 250 with a weight ratio of 15 : 15 : 65 : 1 : 4. Hybrid coatings with different addition amounts of KH570 (0.2, 0.6, 1.0 wt %) were cured from the mixtures by UV‐initiated free‐radical/cationic dual curing technique. Final reactant conversions and photopolymerization rates of the hybrid UV‐cured coatings were improved with the increase of KH570 content, as evaluated by conversion profiles. The morphologies and microstructures were characterized by scanning electron micro‐scopic, atomic force micrographic, and fourier transform infrared spectrophotometer measurements. Thermal, mechanical, and surface properties of the hybrid UV‐cured coatings were investigated. The increase in KH570 content caused a decrease in mechanical properties besides the breaking elongation. Thermo‐gravimetric analysis revealed that the incorporation of silicon into cross‐linked network structure resulted in high thermal stability. The surface properties of hybrid UV‐cured coatings, such as hardness, contact angle, flexibility, and glossiness were also examined. It is found that transparent hybrid coating with the addition of 1.0 wt % KH570 exhibited a relatively higher contact angle as a direct result of a relatively higher hydrophobic surface. These researches showed that micro amounts of small molecular weight silicon‐containing acrylate could greatly influence the morphologies of liquid nitrogen quenching cross sections and properties of hybrid UV‐cured coatings and could be used to modify UV‐cured coatings for some superior properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40655.     

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     

Synthesis and characterization of flame retarding UV‐curable organic–inorganic hybrid coatings

UV‐curable, organic–inorganic hybrid materials were synthesized via sol–gel reactions for tetraethylorthosilicate, and methacryloxypropyl trimethoxysilane in the presence of the acrylated phenylphosphine oxide resin (APPO) and a bisphenol‐A‐based epoxy acrylate resin. The sol–gel precursor content in the hybrid coatings was varied from 0 to 30 wt %. The adhesion, flexibility, and hardness of the coatings were characterized. The influences of the amounts of inorganic component incorporated into the coatings were studied. Results from the mechanical measurements show that the properties of hybrid coatings improve with the increase in sol–gel precursor content. In addition, thermal properties of the hybrids were studied by thermogravimetric analysis in air atmosphere. The char yield of pure organic coating was 32% and that of 30 wt % silicate containing hybrid coating was 30% at 500°C in air atmosphere. This result demonstrates the pronounced effect of APPO on the flame retardance of coatings. Gas chromatography/mass spectrometry analyses showed that the initial weight loss obtained in thermogravimetric analysis is due to the degradation products of the photoinitator and the reactive diluent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1906–1914, 2006     

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     

Stabilized dispersions of titania nanoparticles via a sol–gel process and applications in UV‐curable hybrid systems

Organic–inorganic hybrid UV‐curable coatings were synthesized through blending UV‐curable components and stabilized titania sol prepared via a sol–gel process of tetrabutyl titanate (TBT) with three different stabilizers, acetylacetone (Acac), isopropyl tri(dioctyl)pyrophosphato titanate coupling agent (TTPO) and a polymerizable organic phosphoric acid (MAP). The size and the dispersion of titania particle in the UV‐cured organic matrix were dominated by the properties of these stabilizers. A cured hybrid film with titania particle size around 20 nm was obtained when TTPO was utilized as protection agent for the sol. It is interesting that the hardness and flexibility of the photocured hybrid films were improved simultaneously, in contrast to results with neat organic UV‐curable formulations. Copyright © 2006 Society of Chemical Industry     

UV curable soybean‐oil hybrid systems based on thiol‐acrylate and thiol‐ene‐acrylate chemistry

In this study, epoxidized soybean oil was modified to prepare acrylated epoxidized soybean oil (AESO) and vinyl/acrylate ended soybean oil (VASO), which were blended with mercaptopropyl polyhedral oligomericsilsequioxane (POSS‐SH) to prepare UV curable thiol‐acrylate and thiol‐ene‐acrylate hybrid coatings. Photopolymerization processes of the coatings were measured and the results showed that addition of POSS‐SH obviously increased the conversion of double bond. The physical and mechanical properties of all cured samples were investigated, which indicated that the pencil hardness, tensile strength, and fracture toughness were significantly improved by POSS‐SH. Moreover, with increasing POSS‐SH content, the water contact angles of cured samples were increased, and the water resistance was greatly improved. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42095.     

Effect of hyperbranched acrylates on UV‐curable soy‐based biorenewable coatings

Utilization of biorenewable components in UV‐curable coating formulations is both economically and environmentally beneficial, particularly when compared to their petrochemical‐based counterparts. To produce UV‐curable coatings of high biorenewable content with enhanced performance, acrylated epoxidized soybean oil (ASBO) was combined with biorenewable reactive diluent tetrahydrofufuryl acrylate, adhesion promoters, photoinitiator and hyperbranched acrylates (HBAs) as synthetic tougheners. The HBAs were found to impart high functionality and low viscosity, thus increasing crosslinking in the coating network and improving mechanical and thermal properties such as film hardness, adhesion, solvent resistance, impact resistance, tensile modulus and toughness, glass transition temperature and thermal stability. Real‐time Fourier transform infrared spectroscopy showed decreased acrylate conversion when compared with a reference formulation without HBAs, which was attributed to earlier coating network vitrification during UV irradiation. ASBO‐based coatings were also thermally annealed to allow further reaction of unreacted components in the vitrified network. As a result, coating properties were further improved. Overall, the addition of HBAs as synthetic tougheners to UV‐curable ASBO‐based biorenewable coating systems was shown to greatly improve the corresponding coating properties. Copyright © 2010 Society of Chemical Industry     

Preparation,characterization of UV‐Curable Waterborne Polyurethane‐Acrylate and the application in metal iron surface protection

Hydroxyethyl methyl acrylate (HEMA) capped waterborne polyurethane‐acrylate (WPUA) oligomer was firstly prepared from isophorone diisocyanate (IPDI), polyether polyol (NJ‐220), dimethylolbutanoic acid (DMBA), HEMA via in‐situ and anionic self‐emulsifying method. Ultraviolet (UV) curable WPUA coating was obtained from HEMA‐capped oligomer, butyl acrylate (BA) and multifunctional acrylates (TPGDA) as reactive diluents, and Darocur 1173 as photoinitiator. The physical properties of WPUA oligomers, such as particle size, apparent viscosity, and surface tension were investigated. Some mechanical properties of UV‐WPUA films, such as contact angles, thermal properties, and solvent (water, HCl, NaOH, NaCl, and ethanol) resistance of UV‐WPUA coating films were measured. The surface morphologies were measured by scanning electron microscope and atomic force microscope. The surface free energy of the UV‐cured film was calculated from contact angle measurements using the Lewis acid–base three liquids method. The specific UV‐WPUA coating was selected to protect the iron materials that observed the effect of the protection. The results indicate that the prepared UV‐WPUA coating has excellent protective behavior to metal iron materials and may offer some contributions to protect iron cultural relics. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3142–3152, 2013     

Influence of pigment properties on UV‐curing efficiency

The curable formulations containing monomer‐diacrylate, photoinitiator‐p‐methoxybenzoyldiphenylphosphine oxide/benzyldimethylketal, additive reactive‐triethylamine, and inorganic thermoresistant pigments‐white, red, green, and blue were cured by UV exposure films. A series of experiments was carried out to investigate the relationship between the particle size distribution of the inorganic pigment and the colorimetric and mechanical properties of the UV acrylic curable coatings. Pendulum hardness and appearance of the films depend on the content and particle size distribution of the pigment. Optimal particle size distribution and pigment content were established to obtain the best films concerning their pendulum hardness and chromatic parameters. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 247–252, 2007     

Preparation and properties of fluorinated oligomer with tertiary amine structure in the UV curable coatings

A novel fluorinated oligomer with tertiary amine structure was synthesized by isophorone diisocyanate, 2‐hydroxyethyl acrylate, and fluorinated diol, which was prepared via Michael addition reaction between diethanolamine and dodecafluoroheptyl acrylate. The structure of fluorinated oligomer was confirmed by FTIR. The prepared fluorinated oligomer was added into the UV curable coatings, the influences of fluorinated oligomer on the cured degree and double bond conversion was analyzed by FTIR and gel content. The conversion ratio is increased when the fluorinated oligomer increased, which is due to the tertiary amine structure in the prepared product. The characteristics of UV cured films such as thermal properties, hydrophobicity, chemical resistance, mechanical properties, and hardness were characterized with the TGA, contact angle, and DMA. Results show that thermal stability, hydrophobicity, and chemical resistance are improved when fluorinated oligomer is introduced into the UV curable coatings. The DMA and hardness results indicated that the mechanical properties of UV cured films were improved and the flexibility decreased. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44387.     

UV curable glycidyl carbamate based resins

The synthesis and characterization of UV curable resins based on glycidyl carbamate chemistry have been explored. Glycidyl carbamate (GC) functional resins have been used to obtain crosslinked coatings with a wide range of properties using several crosslinking techniques such as epoxy-amine, self-crosslinking, and sol-gel. GC resin technology was further expanded to UV curable coatings by reacting polyfunctional GC resins with acrylic acid to yield acrylated glycidyl carbamate (AGC) resins. Alcohol-modified UV curable GC resins were also prepared to obtain lower viscosity. Commonly used reactive diluents were used to prepare a UV curable GC coating formulations. The coatings were cured in air using a Fusion LC6B Benchtop Conveyer with an F300 UV lamp. The degree of conversion of acrylic double bonds during UV curing was determined using real time FTIR and showed that the resins had fast cure rates and high extents of conversion of acrylate groups. Coating properties such as hardness, impact strength, methyl ethyl ketone double rubs, flexibility, and adhesion were studied. Dynamic mechanical analysis was used to determine crosslink density of the coatings. Differential scanning calorimetry and thermogravimetric analysis were used to study the thermal properties of the coatings. The type of polyisocyanates and the extent of modification in GC resins influenced the degree of conversion, crosslink density, and coating performance.     

Characterization and properties of UV‐curable polyurethane‐acrylate/silica hybrid materials prepared by the sol‐gel process

UV‐curable, transparent hybrid material of urethane‐acrylate resin was prepared by the sol‐gel process using 3‐(trimethoxysilyl)propylmethacrylate (TMSPM) as a coupling agent between the organic and inorganic phases. The effects of the content of acid and silica on the morphology and mechanical properties of UV‐curable polyurethane‐acrylate/silica hybrid (UA‐TMSPM)/SiO₂ materials have been studied. The results of thermogravimetric analysis for the (UA‐TMSPM)/SiO₂ hybrid materials indicated that the thermal stability of the hybrids is greatly improved. It was found that with the increase of HCl content, the interfacial interaction between organic and inorganic phases had been strengthened, as demonstrated by field emission scanning electron microscopy. Without sacrificing flexibility, the hybrid materials showed improved hardness with increasing content of acid and silica. Compared with the pure organic counterpart UA/hexanediol diacrylate (UA/HDDA) system, abrasion resistance of the hybrids improved with increasing acid content, at low silica content. Copyright © 2004 Society of Chemical Industry     

Fluorine‐containing photocurable hybrid coatings via anhydrous sol–gel method

In this study, fluorine‐doped photocurable hybrid coatings were prepared by combining UV‐curing technology with an anhydrous sol–gel method. First, methacryloxymethyl triethoxysilane (MEMO) was hydrolyzed via an anhydrous sol–gel process. Then MEMO was mixed with acrylic oligomers and predetermined amounts of fluoroacrylate resin. UV curable hybrid coatings were applied on corona‐treated plexiglass substrates. The addition of fluorine showed a significant impact on the properties of the coatings. As the fluorine content was increased in the formulations, flame retardancy and the contact angle values of the coatings increased. It was found that the optical transmittance of the coatings was higher than 95%. The surface morphology of the hybrid films was characterized by scanning electron microscopy (SEM). The chemical composition of the surface of the coatings was identified by energy dispersion spectrum (SEM–EDS) technique. SEM studies indicated that inorganic particles were dispersed homogenously throughout the organic matrix. J. VINYL ADDIT. TECHNOL., 21:272–277, 2015. © 2014 Society of Plastics Engineers     

Surface modification of nanosilica with 3-mercaptopropyl trimethoxysilane and investigation of its effect on the properties of UV curable coatings

This paper describes surface modification of commercial nanosilica with 3-mercaptopropyl trimethoxysilane (MPTMS) and its effect on the properties of UV curable coatings. The mercapto groups were grafted onto nanosilica surface by a condensation of the surface Si–OH with the hydrolysized Si–OH of MPTMS. Fourier transform infrared spectroscopy, thermal gravimetric analysis, and particle size distribution were employed to characterize nanosilica and modified nanosilica. It was demonstrated that the mercapto groups were successfully grafted onto the nanosilica surface with the grafting ratio of 16.8% and the mercapto groups content of 0.9 mmol/g. The dispersion and self-aggregation of nanosilica in UV curable coatings were improved significantly. The photopolymerization kinetics of UV curable coatings, containing various amounts of nanosilica and modified nanosilica, were evaluated by the photo differential scanning calorimetry technique. This indicated that nanosilica both before and after modification decreased UV curing speed and ultimate percentage conversion; however, in comparison with the coatings containing unmodified nanosilica, the coatings containing modified nanosilica exhibited higher curing speeds and conversion ratios. It can be ascribed that the mercapto groups on the nanosilica surface reduced oxygen inhibition during the UV curing process via the thiol–ene click reaction. The mechanical properties of UV curable coatings were also compared.     

Organic‐Inorganic Hybrid Coatings Based on Polyfunctional Silanols as New Monomers in Sol‐Gel Processing

Organic‐inorganic hybrid materials offer the opportunity to combine the desirable properties of organic polymers (toughness, elasticity) with those of inorganic solids (hardness, chemical resistance). Since improved mechanical and chemical resistance is an increasing demand for various coating applications, hybrid materials were developed based on polyfunctional silanols as new monomers in sol‐gel processing. After hydrolysis and condensation with different co‐reactants, coatings with superior optical and mechanical properties are obtained at ambient temperature. Such hybrid coatings show excellent chemical resistance and high UV stability. Although the adhesion to many substrates is good without additional pretreatment, the hybrid coatings exhibit a very anti‐adhesive surface. Due to these properties potential applications include automotive clear coats, hard coats for plastics, anti‐graffiti coatings and biocide‐free fouling‐release coatings.     

Preparation and characterization of UV‐curable organic/inorganic hybrid composites for NIR cutoff and antistatic coatings

In this study, UV‐curable organic/inorganic hybrid composite coatings with near infrared (NIR) cutoff and antistatic properties were prepared by high‐shear mixing of two kinds of polymer matrices and coated on plastic and glass substrates by the doctor‐blade method. This study also investigated the morphology, stability, optical properties, electrical resistivity, and durability of the UV‐cured composite coats. It was found that the composite coatings were very stable under centrifugation. Moreover, the films with transmittance of above 80% in a visible light region (400–800 nm) and of ～ 40% to 50% in the NIR region (1000–1600 nm) showed low haze of 6.9%, electrical resistivity of around 2.3 × 10⁷ Ω/square. Thus, excellent adhesion, scratch, and weathering durability can be produced on polycarbonate substrate at room temperature. The experimental results reveal that UV‐curable organic/inorganic hybrid composites can be used effectively to fabricate films with NIR cutoff as well as antistatic properties, indicating a high potential for practical application in architectural, automotives, and optoelectronics. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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.     

Photopolymerization kinetics and thermal properties of dimethacrylate based on bisphenol‐S

A dimethacrylate based on bisphenol‐S (DBSMA) was prepared and characterized by Fourier Transform infrared spectroscopy (FTIR), Electrospray Ionisation Tandem Mass Spectrometry (ESI/MS) ¹H NMR, and ¹³C NMR. DBSMA was investigated by a real‐time infrared spectroscopy (RTIR), under different conditions such as varying photoinitiator type and concentration, with and without oxygen, mixing with different amounts of a reactive diluent [1,6‐hexanediol dimethacrylate (HDDMA)]. The mechanical and thermal properties of these curing films were also investigated by dynamic mechanical analysis and thermogravimetric analysis. The results showed homopolymer of DBSMA has better thermal stability than copolymers of DBSMA/HDDMA systems. Also, the cured DBSMA polymer exhibited higher glass transition temperature (T_g) and better thermal stability compared with commercial available resin 2,2‐Bis[4‐(2‐hydroxy‐3‐methacryloxypropoxy)phenyl]propane (BIS‐GMA) (CN151). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013