Curing and combustion properties of a PU‐coating system with UV‐reactive phosphazene

A UV‐curable polyurethane (PU)‐coating system containing phosphorus is formulated by the combination of photoinitiator, PU acrylate oligomer, and UV‐reactive phosphazene monomer. PU acrylate oligomer is prepared by the addition of 2‐hydroxyethylmethacrylate (HEMA) to NCO‐terminated PU prepolymer. UV‐reactive phosphazene monomer is derived from the HEMA substitution reaction to hexachlorocyclotriphosphazene (NPCl₂)₃. The curing reaction of this PU‐coating system is carried out by UV irradiation. The resultant UV‐cured PU‐coated films demonstrated better performance properties than those of original UV‐cured PU acrylate (UV‐PU) without UV‐reactive phosphazene monomer. Furthermore, their thermal properties are investigated by a thermogravimetric analyzer and a dynamic mechanical thermal analyzer, respectively. The combustion behaviors of these UV‐cured PU‐coated films are evaluated by the measurements of a limiting oxygen index and a cone calorimeter. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1980–1991, 2002     

Design and UV-curable behaviour of boron based reactive diluent for epoxy acrylate oligomer used for flame retardant wood coating

Difunctional boron-containing reactive flame retardant for UV-curable epoxy acrylate oligomer was synthesized from phenyl boronic acid and glycidyl methacrylate. The synthesized reactive diluent was utilized to formulate ultraviolet (UV)-curable wood coatings. The weight fractions of reactive diluent in coatings formulation was varied from 5 to 25 wt % with constant photoinitiator concentration. The molecular structure of reactive flame retardant was confirmed by Fourier-transform infrared, Nuclear magnetic resonance (NMR) and ¹¹B NMR spectral analysis. Further, the efficacy of flame retardant behaviour of coatings was evaluated using limiting oxygen index and UL-94 vertical burning test. Thermal stability of cured coatings films were estimated from thermogravimetric and differential scanning calorimetry analysis. The effects of varying concentration of reactive diluent on the viscosity of coatings formulation along with optical, mechanical and chemical resistance properties of coatings were also evaluated. The coatings gel content, water absorption behaviour, contact angle analysis and stain resistance were also studied.     

Ultraviolet‐curing behavior of an epoxy acrylate resin system

Ultraviolet (UV)‐curing behavior of an epoxy acrylate resin system comprising an epoxy acrylate oligomer, a reactive diluent, and a photoinitiator was investigated by Fourier transform infrared (FTIR) spectroscopy. The conversion changes of the resin system containing 20 phr of 1,6‐hexanediol diacrylate as a reactive diluent and 2‐hydroxy‐2‐methyl‐1‐phenyl‐propan‐1‐one as a photoinitiator were measured under different UV‐curing conditions. The fractional conversion was calculated from the area of the absorption peak for the vinyl group vibration occurring at 810 cm^?1. The effects of photoinitiator concentration, total UV dosage, one‐step or stepwise UV irradiation, UV intensity, atmosphere, and temperature on the curing behavior of the resin system were investigated. The conversion of the resin system increased rapidly at the initial stage of the UV‐curing process but increased very slowly after that. The final conversion of the resin system was mainly affected by total UV dosage. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1180–1185, 2005     

UV-curable behavior of phosphorus- and nitrogen-based reactive diluent for epoxy acrylate oligomer used for flame-retardant wood coating

Multifunctional phosphorus and nitrogen containing tris-diethanolamine spirocyclic pentaerythritol bisphosphorate reactive diluent (TDSPBRD) for epoxy acrylate oligomer was synthesized from spirocyclic pentaerythritol bisphosphorate diphosphoryl chloride, diethanolamine, and allyl chloroformate. The synthesized reactive diluent was utilized to formulate ultraviolet (UV)-curable wood coating. The weight fraction of reactive diluent in the coating formulation was varied from 5 to 25 wt% with constant photoinitiator concentration. The molecular structure of the reactive flame retardant was confirmed by Fourier transform infrared (FTIR), ¹H nuclear magnetic resonance (NMR) and ³¹P NMR spectral analysis and energy dispersive spectroscopy (EDAX). Further, the effectiveness of the flame retardant behavior of the coatings was evaluated using the limiting oxygen index and UL-94 vertical burning test. Thermal stability was estimated from thermogravimetric analysis and differential scanning calorimetry. The effects of varying the concentration of TDSPBRD on the viscosity of the coating formulation along with the optical, mechanical and chemical resistance properties of the coatings were evaluated. The coatings gel content, water absorption behavior, and stain resistance were also studied.     

A novel UV‐curable epoxy acrylate resin containing arylene ether sulfone linkages: Preparation,characterization, and properties

UV‐curing processes are used in industrial applications because of their advantages such as high‐speed applications and solvent‐free formulations at ambient temperature. UV‐curable epoxy acrylate resins containing arylene ether sulfone linkages (EAAES) were synthesized through the condensation of bis(4‐chlorophenyl)sulphone and bisphenol‐A, followed by end‐caping of epichlorohydrin and subsequently acrylic acid. UV‐cured coatings were formulated with epoxy acrylates, reactive diluents such as pentaerythritol tri‐acrylate and pentaerythritol dia‐crylate and photoinitiator. Fourier transfer infrared, ¹H NMR, and thermal gravimetrical analysis were employed to investigate the structures and thermal properties of the EAs films. The introduction of EAAES into epoxy acrylate substantially improves its thermal properties and thermo‐oxidative stability at high temperatures. In addition, the acrylate containing arylene ether sulfone linkages can also improve pencil hardness and chemical and solvent resistance of the epoxy acrylate. The obtained UV‐curable epoxy acrylate containing arylene ether sulfone linkages is promising as oligomer for UV‐curable coatings, inks, and adhesives in some high‐tech regions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41067.     

Design of holographic polymer‐dispersed liquid crystals based on solubility parameters

BACKGROUND: A slight change of polymer structure leads to a significantly different solubility parameter (SP), which is related to incompatibility and interface anchoring energy between a polymer and a liquid crystal (LC). RESULTS: Holographic gratings in polymer‐dispersed liquid crystals have been fabricated based on various urethane acrylate oligomer sizes and type of reactive diluent at two LC loadings. A large SP gap, using N‐vinylpyrrolidone as reactive diluent, gave much faster saturation of diffraction efficiency at higher level, but the grating failed to operate. On the contrary, films having a small SP gap, using 2‐ethylhexyl acrylate, operated under 20 V with a response time of about 10 ms, although their saturation of diffraction efficiency was relatively low. The results were interpreted in terms of morphology (determined using scanning electron microscopy), anchoring energy and resin elasticity. CONCLUSION: Low driving voltage and high diffraction efficiency are obtained by controlling the SP gap between LC and polymer. Copyright © 2007 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     

Water‐borne melamine–formaldehyde‐cured epoxy–acrylate corrosion resistant coatings

Organic protective coatings are widely used in corrosion control. However, environmental standards establish that the volatile organic compounds either must be removed or controlled at the lowest possible levels. The carcinogenic environmental impact of volatile organic compounds has led to the substitution of solvent‐borne coatings by water‐borne coating systems. Among recently developed water‐borne coatings, epoxy‐ and acrylic‐based coatings have a special significance over other reported water‐borne systems. Keeping in mind, the importance of water‐borne coatings in the present work, we report the synthesis of water‐borne epoxy–acrylate (EpAc) and melamine–formaldehyde (MF) as well as formulation of their anticorrosive coatings. The structural elucidation of MF‐cured EpAc was carried out by FTIR, ¹H NMR, and ¹³C NMR spectroscopic techniques. The coatings of EpAc‐MF were applied on mild steel strips and were evaluated for physicochemical, physicomechanical characterization, and the anticorrosive performance under different environmental conditions. The present coating system EpAc coatings exhibited superior performance as compared to the reported water‐borne epoxy–acrylatecoatings. The presence of melamine–formaldehyde in the resin increases the scratch hardness, impact resistance, alkali resistance, and thermal stability of these coatings. EpAc‐MF‐1 was found to cure at ambient temperature and exhibit good physicomechanical properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Ultraviolet‐curing behavior and mechanical properties of a polyester acrylate resin

Ultraviolet (UV) curing technology has been widely used in many applications because it has several distinct advantages compared to solvent‐based processes or thermal‐curing technology. The effects of photoinitiator types and their contents as well as reactive diluent types and their contents on the UV‐curing behavior and mechanical properties of a UV‐curable polyester acrylate resin were investigated in this study. Three photoinitiators, Irgacure 184, Darocur 1173, and benzophenone, were used in this study. Hexanediol diacrylate, tripropylene glycol diacrylate, and trimethylol propane triacrylate were used as reactive diluents to modify the properties of the acrylate resin. The change of chemical structure during UV curing was monitored by FTIR. A universal testing machine was used to measure the tensile properties of various UV‐cured acrylate films of different compositions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3921–3928, 2004     

An efficient fully bio‐based reactive diluent for epoxy thermosets: 2‐[(Oxiran‐2‐ylmethoxy) methyl] furan versus a petroleum‐based counterpart

Furfuryl alcohol and bio‐based epichlorohydrin were used to prepare a fully bio‐based reactive diluent, 2‐[(oxiran‐2‐ylmethoxy) methyl] furan (FOM). After spectral characterization, FOM was blended with epoxy resin, diglycidylether bisphenol A (DGEBA), at different ratios for reducing the viscosity. For a comparison, Cardura (one of the most common commercial reactive diluents), was separately incorporated to DGEBA. Amine‐curing process of the blends was recorded by FTIR and DSC. Similar trends of curing progression for DGEBA containing the reactive diluents were observed. Thermogravimetric analysis and dynamic mechanical thermal analysis, mechanical (hardness, adhesion, and stress–strain) and morphological properties were also investigated to study characteristics of the epoxy matrices formulated with FOM or Cardura. It was concluded that FOM could be considered as an efficient reactive diluent in formulations of polymer composites, structural adhesives and surface coatings based on epoxy resins. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44957.     

A novel type of Si‐containing acrylic resins: Synthesis,characterization, and film properties

A novel type of Si‐containing acrylic resins was prepared by two steps and investigated their usage as surface coatings materials. At first a reactive polysiloxane intermediate Z‐6018 was reacted with 2‐hydroxyethyl methacrylate (HEMA) in toluene at 110°C under N₂ atmosphere. After the condensation reaction was stopped, reacted with different acrylic ester monomers such as ethyl acrylate (EA) and methyl methacrylate (MMA) at different mole ratio (1/3 and 1/4) by the free radical addition polymerization. Structures of Si‐containing acrylic resins were characterized by Fourier Transform Infrared Spectrometer (FTIR) and thermal properties of these resins were investigated by thermogravimetric analysis and differential scanning calorimetry DSC techniques. Surface coating properties of the films prepared from these resin were also determined. The results showed that all films are flexible, glossy or semi gloss and have excellent drying and adhesion properties. All films also exhibit abrasion resistances moderately. Water resistance of the films was generally modified by cured in oven and alkaline resistance of the films prepared from resins containing ethyl acrylate units are excellent. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Study of impact properties and morphology of 4,4′‐diaminodiphenyl methane cured epoxy resin toughened with acrylate‐based liquid rubbers

Randomized carboxyl poly(2‐ethylhexyl acrylate) (A‐1) and randomized epoxy poly(2‐ethylhexyl acrylate) (B‐1) rubbers were synthesized in the form of liquid rubber by a solution polymerization technique. The liquid rubbers A‐1 and B‐1 were characterized by ¹H NMR and IR spectroscopic analysis, non‐aqueous titration, viscosity measurements and gel permeation chromatography. The liquid rubbers A‐1 (M?_n = 3900 g mol^?1), B‐1 (M?_n = 4100 g mol^?1) and a (1:1) mixture of A‐1 and B‐1 were pre‐reacted with epoxy resin separately and the modified epoxy networks were made by curing with high temperature curing agent. The modified epoxy networks were evaluated by unnotched Izod impact testing. The morphology and toughening behaviour were analysed by scanning electron microscopy. Optimum properties were obtained with the mixture of A‐1 and B‐1. Copyright © 2003 Society of Chemical Industry     

Photopolymerization and thermal behavior of phosphate diacrylate and triacrylate used as reactive‐type flame‐retardant monomers in ultraviolet‐curable resins

Tri(acryloyloxyethyl)phosphate (TAEP) and di(acryloyloxyethyl)ethyl phosphate (DAEEP) were used as reactive‐type flame‐retardant monomers along with commercial epoxy acrylate and polyurethane acrylate oligomers in ultraviolet (UV)‐curable resins. The concentrations of the monomers were varied from 17 to 50 wt %. The addition of the monomers greatly reduced the viscosity of the oligomers and increased the photopolymerization rates of the resins. The flame retardancy and thermal degradation behavior of the UV‐cured films were investigated with the limiting oxygen index (LOI) and thermogravimetric analysis. The results showed that the thermal stability at high temperatures greater than 400°C and the LOI values of the UV‐cured resins, especially those containing epoxy acrylate, were largely improved by the addition of the monomers. The dynamic mechanical thermal properties of the UV‐cured films were also measured. The results showed that the crosslink density increased along with the concentrations of the monomers. However, the glass‐transition temperature decreased with an increasing concentration of DAEEP because of the reduction in the rigidity of the cured films, whereas the glass‐transition temperature increased with the concentration of TAEP because of the higher crosslink density of the cured films. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 185–194, 2005     

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     

Upgrading the adhesion properties of a fast‐curing epoxy using hydrophilic/hydrophobic hyperbranched poly(amidoamine)s

A homologous series of hyperbranched polymers (HBPs) was prepared following a well‐defined method and their formation in a polymeric form bearing different extents of branching with amine functional groups at the terminals was verified using different techniques such as Fourier Transform Infrared, ¹H Nuclear Magnetic Resonance, Differential Scanning Calorimetry, and Gel Permeation Chromatography. Toughening of a commercially available fast cure epoxy was aimed through reactive blending with the formed HBPs that exhibit variation in polarity and branching according to the relevant synthesis strategy employed for each polymer. The mechanical properties (impact resistance, pull‐off adhesion, and bending) of the resulting coating films pertaining to each epoxy formulation after adhering to metal substrates revealed obvious progress in their performance with respect to a control sample that was hardened exclusively in absence of any HBP. The results were explained on the light of the ability of this class of materials to impose flexibility and dilute the intensive crosslink density associated frequently with the rapid curing of epoxy systems. The extent of gained enhancement for each formulation was accounted for by the molecular architecture of the HBPs, their degrees of branching, polarity, and relative reactive contents of primary amino groups in each case. In addition, the influence of these parameters on a proper wetting over the substrate and morphology of the films in each case was also studied using scanning electron microscopy. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Light cured fluoride filled denture‐coating materials

Light cured denture‐coating materials were prepared by formulating an acrylate monomer with a photoinitiator system (camphorquinone and dimethylaminoethyl methacrylate) using one of three base monomers [bisphenol A glycerolate diacrylate (Bis‐GDA), glycerol 1,3‐diglycerolate diacrylate (GDA), and diurethane dimethacrylate (DU‐DMA)] each with four diluents [triethylene glycol dimethacrylate (TEGDMA), di(ethylene glycol) methyl ether methacrylate, 2‐hydroxyethyl methacrylate (HEMA), and methacrylic acid (MAA)] at a fixed 1 : 1 molar ratio of base monomer to diluent. The twelve formulations were then evaluated for their surface hardness and water sorption as coating materials. The DU‐DMA/MAA, DU‐DMA/HEMA, Bis‐GDA/HEMA, and GDA/MAA based coatings provided a high level of both surface hardness and water sorption properties. When sodium fluoride (NaF) or calcium fluoride (CaF₂) was incorporated into those formulations, the fluoride ion release rate from all four NaF containing coating materials was extremely high in the first week, decreasing sharply in the second week and then decreasing in the later 2 weeks. In contrast, the CaF₂ containing coating materials showed a slower sustained rate of fluoride ion release over the 4‐week test period, with the DU‐DMA/HEMA based coating having a fluoride ion release pattern that meets the requirements for dental use. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Dendritic carbosilane‐based macrophotoinitiator: synthesis,characterization, and photoinitiating behavior

A novel radical dendritic macrophotoinitiator, bearing alkyl pheone moieties linked to the surface of the dendrimer, was synthesized via alcoholysis of carbosilane dendrimer and the small‐molecule photoinitiator 2‐hydroxy‐2‐methyl‐1‐(4‐tert‐butyl)phenylpropane‐1‐one. The structure of the dendritic carbosilane‐based macrophotoinitiator (MPI) was characterized using Fourier transform infrared spectroscopy, ¹H NMR, ¹³C NMR, ²⁹Si NMR, elemental analysis, size exclusion chromatography/multi‐angle laser light scattering, UV‐visible spectroscopy, and differential photocalorimetry (DPC). UV‐visible analysis indicates that the absorption band of photosensitive moieties shifts towards high wavelength by introducing the carbosilane dendrimer core. The DPC results demonstrate that the initiating efficiency of MPI is effective when using epoxy acrylate (EA) as a model resin. Furthermore, thermogravimetric analysis of cured EA resin indicates that the thermal stability can be improved markedly by the incorporation of MPI in the curing formulation. Copyright © 2007 Society of Chemical Industry     

Modification of UV‐cured epoxy resins with fluorescent sensors through photopolymerization and click chemistry reactions and preparation of polarity‐sensitive films

In this work, functionalization of epoxy films with dansyl and naphthalimide fluorophores is described. The procedure involves UV‐photopolymerization of an epoxy formulation that includes bromomethyl reactive groups, and their post‐functionalization modification through a click strategy. Quantitative click reaction within the bulk of the film allows one to obtain films in which the fluorophore is uniformly and covalently linked throughout the epoxy network. Depending on the chromophore bounded, the films are sensitive to different stimuli. Evaluation of the fluorescence emission of the films shows a linear response towards changes in polarity but less sensitivity than that of the low‐molecular‐weight chromophore. © 2013 Society of Chemical Industry     

Effect of pigment colour on the printing performance of synthetic leather using a ultraviolet‐curable water‐borne polyurethane acrylate binder

The effect of pigment colours, cyan (C), magenta (M) and yellow (Y), and a blend of these (CMY blend) on the printing performance of synthetic leather using a ultraviolet (UV)‐curable water‐borne polyurethane acrylate binder and two types of photoinitiators was investigated. The curing process was carried out at different radiation doses using gallium and mercury UV lamps in combination. The performance of the prints was evaluated with abrasion resistance, crock fastness, gloss and hardness values and K/S. Chemical changes in the cured film structures due to UV curing were analysed by Fourier Transform–infrared spectroscopy measurements. The highest hardness values for clear and pigmented cured films were obtained with a gallium and mercury lamp combination at the highest energy density (1529 mJ/cm²). The highest K/S was obtained for the sample printed with the formulation including the C pigment and cured under a gallium and mercury lamp combination at low energy density (398 mJ/cm²). The M‐pigmented film displayed the highest hardness and abrasion resistance, whereas lower values were obtained with films pigmented with Y and C, and CMY blend, successively. The highest dry and wet crock values were obtained with the formulation including the M pigment. CMY‐pigmented film showed the highest gloss values at all energy densities. The pigment colour affected the curing degree of printed films due to the different absorption/transmission intervals of each colour in the UV spectrum.     

Preparation and drug‐release behavior of minocycline‐loaded poly[hydroxyethyl methacrylate‐co‐poly(ethylene glycol)–methacrylate] films

In this work, biocompatible hydrogel matrices for wound‐dressing materials and controlled drug‐release systems were prepared from poly[hydroxyethyl methacrylate‐co‐poly(ethylene glycol)–methacrylate] [p(HEMA‐co‐PEG–MA] films via UV‐initiated photopolymerization. The characterization of the hydrogels was conducted with swelling experiments, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis (differential scanning calorimetry), and contact‐angle studies. The water absorbency of the hydrogel films significantly changed with the change of the medium pH from 4.0 to 7.4. The thermal stability of the copolymer was lowered by an increase in the ratio of poly(ethylene glycol) (PEG) to methacrylate (MA) in the film structure. Contact‐angle measurements on the surface of the p(HEMA‐co‐PEG–MA) films demonstrated that the copolymer gave rise to a significant hydrophilic surface in comparison with the homopolymer of 2‐hydroxyethyl methacrylate (HEMA). The blood protein adsorption was significantly reduced on the surface of the copolymer hydrogels in comparison with the control homopolymer of HEMA. Model antibiotic (i.e., minocycline) release experiments were performed in physiological buffer saline solutions with a continuous flow release system. The amount of minocycline release was shown to be dependent on the HEMA/PEG–MA ratio. The hydrogels have good antifouling properties and therefore are suitable candidates for wound dressing and other tissue engineering applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009