Epoxy Acrylate Research Articles

Photocurable Epoxy Acrylate Coatings Preparation by Dual Cationic and Radical Photocrosslinking

In this work, epoxy acrylate resin (EA) based on the industrial-grade bisphenol A-based epoxy resin (Ep6) and acrylic acid (AA) has been synthesized in order to develop hybrid resin comprising both epoxide group and reactive, terminal unsaturation. Obtained epoxy acrylate prepolymer was employed to formulate photocurable coating compositions containing, besides the EA binder, also cationic or radical photoinitiators. Hence, when cationic photoinitiators were applied, polyether-type polymer chains with pending acrylate groups were formed. In the case of free radical polymerization, epoxy acrylates certainly formed a polyacrylate backbone with pending epoxy groups. Owing to the presence of both epoxy and double carbon–carbon pendant groups, the reaction product exhibits photocrosslinking via two distinct mechanisms: (i) cationic ring-opening polymerization and (ii) free radical polymerization. Therefore, photopolymerization behavior of synthetized hybrid resin with various photoinitiators was determined via photo-differential scanning calorimetry (photo-DSC) and real-time infrared spectroscopy (RT-IR) methods, and properties of cured coatings were investigated. The performance of the following type of photoinitiators was tested in the cationic photopolymerization: diaryliodonium cations or triarylsulfonium cations, and the following type of photoinitiators were used to induce free radical photopolymerization: α-hydroxyketones, acylphosphine oxides, and their mixtures. Lastly, the basic physicomechanical properties of cured coatings, such as tack-free time, hardness, adhesion, gloss, and yellowness index, were evaluated. Some structural factors and parameters of cationic and radical photoinitiators and photopolymerization mechanisms affecting the epoxy acrylate hybrid coatings performance are discussed.

Controlled preparation and properties of acrylic acid epoxy‐acrylate composite emulsion for self‐crosslinking coatings

AbstractA stable epoxy‐acrylate composite latex was successfully prepared through emulsion polymerization of modified epoxy acrylic (EPAC) oligomer with acrylate monomer. The EPAC oligomer was obtained using active acrylic acid (AA) to react with epoxy resin. And by regulating the reaction degree of the active hydrogen of AA and epoxide group, there is the acquisition of terminal double bond that gives EPAC reactivity, together with the partial retention of the epoxide group that enables self‐crosslinking during film formation. The structural conformation of the oligomer was ascertained by Fourier transform infrared (FTIR) spectroscopy. The factors influencing the stability of the epoxy‐acrylate composite latex were investigated. The epoxy‐acrylate composite latex was the most stable when methyl acrylic acid was 1.5 wt% and modified EPAC oligomer was 15 wt% of the total monomer weight. The morphology and property of the composite latex films were characterized by scanning electron microscopy, transmission electron microscopy (TEM), and temperature‐modulated differential scanning calorimetry (TOPEM‐DSC). The results confirm that there is successful emulsion copolymerization between modified EPAC oligomer and acrylate monomer. TEM show that the particles of epoxy‐acrylate composite have a core‐shell structure, and there is no free epoxy resin. The FTIR and TOPEM‐DSC results reveal that the copolymer emulsion possesses self‐crosslinking ability. During film formation, self‐crosslinking reaction occurs between epoxide groups with carboxyl groups, giving exothermal phenomena. The thermal stability as well as the corrosion resistance of the films was analyzed. The results show outstanding thermal stability as well as corrosion resistance attributable to the crosslinking reticulation structure. It is envisaged that the epoxy‐acrylate composite latex has great potential in the development of high‐performance aqueous coatings.

Thermal, dynamic-mechanical and electrical properties of UV-LED curable coatings containing porcupine-like carbon structures

In this work, multi-functional coatings based on a UV-LED curable epoxy-acrylate resin and different loadings (namely, 1, 2.5, 5 and 10 wt%) of carbonaceous structures having a peculiar porcupine (PuP)-like morphology were formulated and thoroughly characterized through thermal, dynamic-mechanical and electrical analyses. More specifically, biochar-based particles derived from cellulose nanocrystals were modified through the growth of carbon nanofibers onto their outer surface, aiming at combining the effects of globular and high aspect ratio structures in a single filler. The preliminary characterization of the carbonaceous structures documented the achievement of a highly carbonized material involving spherical biochar particles having an average diameter ranging from 15 to 20 µm, covered by fibers displaying length up to 100 µm. As assessed by dynamic-mechanical characterization, the UV-LED cured composite films showed a progressive increase of the storage modulus values as a function of the amount of embedded PuP structures, indicating a strong level of interfacial interactions between the polymer network and the particles. Furthermore, the introduction of increasing amounts of PuPs induced a progressive increase of the material thermal conductivity (from 0.109 W/mK for unfilled cured resin, up to 0.161 W/mK, for the composite film containing 10 wt% of filler) and a remarkable enhancement of the electrical conductivity (up to (3.1 ± 0.2)*10−2 S/m, for the composite film containing 10 wt% of filler), thus pointing out the effectiveness of the proposed approach of surface modifying biochar particles in obtaining composite coating films with superior properties.

Obtaining a combined epoxy-acrylic dispersion

The current state of development of the economy of the Russian Federation causes the appearance of a number of urgent problems related to improving production and increasing the level of environmentally safe products, in particular paints and varnishes combined with high performance properties of coatings based on them. In this regard, the advantages and disadvantages of aqueous dispersions based on polymers in the presence of various modifiers that are widely used in the paint and varnish industry were analyzed. This article discusses the problem of stability conditions for mixed materials of epoxy-acrylic type and the establishment of a relationship between the composition of the film-forming base and the performance properties of coatings. The purpose of this study is to create new water-dispersion paints and varnishes based on mixed epoxy-acrylic film-formers for coatings with increased hardness, wear resistance, elasticity and adhesion. The analysis of the main types of water-based film-forming agents is carried out. It is proposed to use mixed systems of film-formers based on epoxy-acrylic dispersions. It was established by standard methods that by combining dispersions of acrylic and epoxy types it is possible to achieve a significant increase in the wear resistance of the compositions (almost 2 times) in comparison with the wear resistance of materials based on acrylic. The adhesion of coatings to substrates of various nature (except for brick) increases with an increase in the content of the epoxy component. In terms of performance, acrylic epoxy can be more effective than acrylic and can be used in humid environments. An increase in the performance properties of these materials in comparison with acrylate systems has been confirmed. It should be noted that an additional task in the development of any building materials is affordability. It is known that not all dispersions are cheap, for example, in the presence of silicone polymers, dispersions are expensive, so they are used only when necessary. To improve operational properties and reduce the cost of protective coatings, we proposed using composite materials, which included styrene-acrylic and epoxy aqueous dispersions. In the future, it is planned to create “smart” materials whose properties will depend on functional fillers.

Antimicrobial uv curable wood coatings based on citric acid

PurposeEpoxy acrylate which is commercially utilized for UV curable coatings although has excellent adhesion, flexibility, hardness and chemical resistance, they lack in antimicrobial properties. Citric acid (CA) is economical as well as a bio-based compound which possess an antimicrobial activity. So, the purpose of this research investigation is the preparation of CA-based oligomer which can be further incorporated with epoxy acrylate and tri (propylene glycol) Diacrylate (TPGDA) to form uv curable coating and the study of its antimicrobial property.Design/methodology/approachA UV-curable unsaturated oligomer (CUV) was synthesized from CA and glycidyl methacrylate (GMA). The chemical structure of CUV was confirmed by FTIR, 1H NMR, GPC, hydroxyl value, acid value and iodine value. Further, CUV was assimilated as an antimicrobial as well as crosslinking agent to copolymerize with epoxy acrylate oligomer and a series of UV-cured antimicrobial coatings were concocted by employing UV-curing machine. The consequence of varying the fraction of CUV on the mechanical, chemical, thermal and antimicrobial properties of UV-cured wood coatings was explored.FindingsResults exhibited good mechanical, chemical and thermal properties. In addition, it was perceived that the zone of inhibition against S. aureus got enlarged with increasing content of CUV in the coating formulation.Originality/valueThe synthesized bio-based CUV reveals an extensive potential to ameliorate the antimicrobial properties of UV-curable coatings.

EPOXYACRYLATE-BASED PHOTOPOLYMERIZABLE COMPOSITIONS FOR THERMOOXIDATIVE RESISTANT MATERIALS

The characteristics of thermooxidative degradation of the samples of cured epoxy acrylates based on epoxy resins ED-20 and UP-637, as well as their compositions with oligoether acrylate TGM-3, were investigated by the method of simultaneous thermal analysis. It has been found that the photopolymers have a sufficiently high resistance to thermal oxidation, the start temperature of active thermal destruction exceeds 325 ° C. Differences in the chemical structure of the aromatic fragment determine the features of thermal resistance. The addition of an active diluent to the composition is capable to reduce the internal stresses of the polymer structure and to promote a shift in the onset of thermal oxidation to higher temperatures.

Novel Multifunctional Epoxy (Meth)Acrylate Resins and Coatings Preparation via Cationic and Free-Radical Photopolymerization.

In this work, a series of novel multifunctional epoxy (meth)acrylate resins based on a low-viscosity aliphatic triepoxide triglycidyl ether of trimethylolethane (TMETGE) and acrylic acid (AA) or methacrylic acid (MMA) have been synthesized. Thanks to the performed modification, the obtained prepolymers have both epoxides as well as carbon–carbon double bonds and differ in their amount. The obtained results indicate that the carboxyl-epoxide addition esterification occurs in the presence of a catalyst (triphenylphosphine) at a temperature of 90 °C, whilst the required degree of conversion can be achieved simply by varying both the reagents ratio and reaction time. The structure of synthesized copolymers was confirmed by spectroscopic analyses (FT-IR, 1H NMR, 13C NMR) and studied regarding its nonvolatile matter content (NV), acid value (PAVs), as well as its epoxy equivalent value (EE). Due to the presence of both epoxy and double carbon–carbon pendant groups, one can apply two distinct mechanisms: (i) cationic ring-opening polymerization or (ii) free-radical polymerization to crosslink polymer chains. Synthesized epoxy (meth)acrylate prepolymers were further employed to formulate photocurable coating compositions. Hence, when cationic photoinitiators were applied, polyether-type polymer chains with pending acrylate or methacrylate groups were formed. In the case of free-radical polymerization, epoxy (meth)acrylates certainly formed a poly(meth)acrylate backbone with pending epoxy groups. Further, photopolymerization behavior and properties of cured coatings were investigated regarding some structural factors and parameters. Moreover, reaction rate coefficients of photo-cross-linking by both cationic ring-opening and free-radical photopolymerization of the received epoxy (meth)acrylate resins were determined via real-time infrared spectroscopy (RT-IR). Lastly, basic physicomechanical properties, such as tack-free time, hardness, adhesion, gloss, and yellowness index of cured coatings, were evaluated.

Lignin doped epoxy acrylate sandwich electromagnetic shielding material synergized with Fe3O4 and CNT

A kind of novel electromagnetic shielding sandwich coating material with excellent electromagnetic interference shielding and coating properties was explored in this work. The interlayer was obtained through the in situ reaction of lignin, epoxy and acrylate doped with modified Fe3O4 nanoparticles (Fe3O4) and multi-wall carbon nanotubes (CNT) (FCLBEA). The FCLBEA layer was coated by two layers of lignin-based epoxy acrylate (LBEA) on both sides, and the total thickness was only around 1 mm. The SEM image showed that the Fe3O4 and CNT are uniformly dispersed in the LBEA matrix. The electromagnetic interference shielding efficiency (EMI SE) of LBEA@FCLBEA@LBEA sandwich material (LFL) was tested in the frequency range of 8.2–18 GHz, and the EMI SE value was higher than 10 dB in the entire measurement range. When the content of Fe3O4 and CNT was both 5% and the lignin content was 15%, the maximum EMI SE reached 14.8 dB. The LFL showed excellent hardness (4H) and adhesion (standard 1). The lignin enhanced the mechanical properties of LFL due to its benzene ring skeleton structure. In addition, the benzene ring of lignin interacted with CNT through π-π bond, which enhanced the dispersion of carbon nanotubes and Fe3O4 in the matrix, and promoted a complete electronic network formed in the system. The most important, the benzene ring in lignin has certain electromagnetic shielding effect, and can also form a synergistic effect with Fe3O4 and CNT to enhance the electromagnetic shielding performance. It was illustrated that the LBEA@FCLBEA@LBEA sandwich material with excellent overall properties can be promising in wide applications, such as EMI coatings, dark room and military fields.

Photosensitive Composite Inks for Digital Light Processing Four-Dimensional Printing of Shape Memory Capture Devices.

High-performance shape memory thermosetting polymers and their composites for four-dimensional (4D) printing are essential in practical applications. To date, most printable thermosets suffer from complicated processes, poor thermodynamic performances, and low printing speed. Here, photosensitive composite inks for fast photocuring printing are developed. The inks consist of epoxy acrylate (EPAc), polyethylene glycol dimethacrylate (PEGDMA), and carbon fillers, which form a firm network structure when exposed to UV light. EPAc is synthesized via addition esterification of epoxy resin and acrylic acid under mild conditions. It is worth noting that raw materials for the reaction are diverse, including not only various epoxy resins but also molecules with epoxy groups. The 4D printing speed of up to 180 mm/h is mainly attributed to the exothermic reaction initiated by free radicals, which accelerates the polymerization of EPAc and PEGDMA. Most importantly, by increasing the exposure time of each layer from 1 s to 3 s during the printing process, the epoxy composite-infilled carbon nanotubes and carbon fibers are printed to ensure the integrity of the microlayer structure. Furthermore, we design a claw-like catcher device based on the above printable composite inks to demonstrate its potential applications in aerospace, such as grasping end-of-service spacecraft or explosive debris. Undoubtedly, 4D printing technology opens up a new portal for the manufacturing of thermoset epoxy composites and complex structures, which make the shape memory thermosetting epoxy resins and their composites possess excellent properties and good engineering application prospects.

Preparation and photochemical properties of PEG based alpha-hydroxyalkylphenone photoinitiator

A novel emulsified photoinitiator (named as OP10-IPDI-2959) was prepared by the reaction of isophorone diisocyanate (IPDI) with 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone (Ir-2959) and nonylphenol polyoxyethylene ether (OP-10). The structure of OP10-IPDI-2959 was characterized by FT-IR, 1H NMR, UV–vis and high-resolution mass spectrometry. The photochemical behavior of OP10-IPDI-2959 was investigated through the photolysis and polymerization of neopentyl glycol diacrylate (NPGDA), mixture of epoxy acrylate resin and 1,6-hexanediol diacrylate (HDDA). Under irradiation of UV light, the OP10-IPDI-2959 has similar photochemical properties with the Ir-2959. Combined with benzophenone, the photoinitiated rate of OP10-IPDI-2959 is higher than that of Ir-2959. The polyoxyethylene fragment of OP10-IPDI-2959 is not only an alternative to toxic amine as hydrogen donor, but also a hydrophilic unit for interface between oil and water. The OP10-IPDI-2959 can effectively emulsify the epoxy acrylate resin and 1,6-hexanediol diacrylate mixture to form low viscosity emulsion. Compared with Ir-2959, OP10-IPDI-2959 has good photoinitiation activity, lower migration and good water emulsification performance.

Graphene oxide/epoxy acrylate nanocomposite production via SLA and importance of graphene oxide surface modification for mechanical properties

PurposeTraditional nanocomposite production methods such as in situ polymerization, melt blending and solvent technique, have some deficits. Some of these are non-homogeneous particle distribution, setup difficulties, time-consuming and costly. On the other hand, three-dimensional printing technology is a quite popular method. Especially, Stereolithography (SLA) printing offers some benefits such as fast printing, easy setup and smooth surface specialties. Furthermore, surface modification of Graphene Oxide (GO) and its effects on polymer nanocomposites are quite important. The purpose of this study is to examine the effect of surface modification of GO nanoparticles on the mechanical properties and morphology of epoxy acrylate (BisGMA/1,6 hexane diol diacrylate) matrix nanocomposites.Design/methodology/approachIn this study, Ultraviolet (UV) curable end groups of synthesized resin were linked to functional groups of graphene oxide, which are synthesized by the Tour method, which is a kind of modified Hummer method. In addition, synthesized GO nanoparticle’s surfaces were modified by 3-(methacryloyloxy) propyl trimethoxysilane. Significant weight percentages of GO were added into the epoxy acrylate resin. Different Wt.% of modified graphene oxide/acrylate resins was used to print test specimens with SLA type three-dimensional printer.FindingsSurface modification has a significant effect on tensile strength for graphene oxide nanoparticles contained composites. In addition, a specific trend was not observed for tensile test results of non-modified graphene oxide. The tendency of impact and hardness test finding were similar for both surfaces modified and non-modified nanoparticles. Finally, the distribution of particles was homogeneous.Originality/valueThis paper is unique because of the inclusion of both surface modifications of graphene oxide nanoparticles and SLA production of nanocomposites with its own production of three-dimensional printer and photocurable polymer resin.

A bio-derived char-forming strategy for surface fireproofing: Functionalization of UV-curing flame-retardant coating with vinyl-modified tannic acid

In this work, a bio-derived char-forming strategy for surface fireproofing was developed. Specifically, a vinyl-modified tannic acid, (VTA) was synthesized by a ring-opening reaction between tannic acid and glycidyl methacrylate. Integration of epoxy acrylate resin, VTA and tri-(glycidyl methacrylate) phosphate (TGMA), a novel UV-curing coating was prepared, which rendered the PET sheets with superior fireproofing effect. PET samples that were surface coated with the designed UV-curing agent displayed a UL-94 V-0 rating. The peak heat release rate (peak HRR) for combustion of PET was reduced by 10.66% upon application of the flame-retardant coating in cone calorimetry tests. However, the total smoke release (TSR) increased by 48.28% due to pyrolysis of tannic acid produces 1,2,3-benzenetriol and carbon dioxide, plus the triol underwent partial combustion with the formation of large amount of particulates. The thermal behavior of cured coating revealed that the presence of high carbon content aromatic tannic acid promoting cationic crosslink and char formation ability. When 40% VTA was added into a coating, the pyrolysis char yield increased by 36.88%. Furthermore, the capability of inhibit heat transfer with the presence of VTA significantly decreased the maximum rate of weight loss for the coating by 85.97%. The increase in the VTA content promoted crosslinking density of the coating, which leads to good rigidity, outstanding abrasion resistance and remarkable water fastness.

Dual Microcapsulation of an Environmentally‐Friendly‐Based Reactive Multifunctional Acrylated Epoxy Resin and Thiol by Internal Phase Separation Technique for Self‐healing Applications

In this research, the microcapsules were individually prepared via internal phase separation technique using reactive bio-based acrylated epoxidized soybean oil, AESO, and trimethylolpropane tris(3-mercaptopropionate), TMPMP as healing and curing agents respectively in PMMA shell for self-healing intentions. The desired variables used were the ratio of the shell/core, the type of surfactant (ionic and polymeric) and PMMA molecular weights. FTIR confirmed very fast crosslinking reaction between reactive epoxy and acrylate functional groups in AESO and thiol groups in TMPMP, which is very important for self-healing purposes. Furthermore, FTIR and thermal characterization results confirmed the encapsulation of both the resin and the curing agent components in two different core–shell microcapsules. The surface morphology of microcapsules obtained changed from dimpled and holed to plain for AESO and TMPMP respectively suggesting that it depends strongly on the nature of the core, type of surfactant and the ratio of shell/core. The produced core–shell microcapsules had a mean diameter of 7.9–169.7 µm and 9.9–64.1 µm for AESO/PMMA and TMPMP/PMMA, respectively. With changing the percentage of shell revealed that increasing the PMMA dosage in both surfactants causes a decrease in the size of TMPMP-filled microcapsules.

Thiol‐terminated hyperbranched polymer for DLP 3D printing: Performance evaluation of a low shrinkage photosensitive resin

AbstractIn order to lower the volume shrinkage of the DLP 3D printing photosensitive resins during printing, a thiol‐terminated hyperbranched polymer (T‐HBP) was synthesized and introduced into the bisphenol A epoxy acrylate (EA) based photosensitive resin system. The obtained T‐HBP was characterized by FTIR and 1H NMR spectra, and the grafting rate of sulfhydryl was determined. The mechanical properties of the photosensitive resins were measured by tensile and impact strength measurement. The glass transition temperature of the photosensitive resins was analyzed by DSC and the impact fracture surface was observed by SEM. T‐HBP exhibited a much lower viscosity than its linear counterparts, and the addition of thiol improved the curing speed of the photosensitive resins. When the amount of T‐HBP added was 20 wt%, the shrinkage of the photosensitive resins was reduced by about 45.5% and the impact strength increased by 33.9% compared with the control. The macromolecular spherical structure of T‐HBP effectively reduced the functional group density of the photosensitive resins. In addition, the thiol‐acrylate photopolymerization introduced by T‐HBP further reduced the volume shrinkage of the photosensitive resins.

Density Functional Theory-Assisted Synthesis of Self-Curing Epoxy-Acrylic Resin.

A density functional theory-assisted synthesis of self-curing epoxy–acrylic resin (EMPA) is described. The calculated quantum chemistry reaction index of the reacting monomer in the basic state, i.e., the radical reaction index (Fk0), is used as a guide to optimize the synthesis conditions. The reliability of the Fk0-assisted synthesis method is confirmed after evaluating the physical appearance, mechanical properties after curing, and thermal stability of the obtained EMPA. The special functional groups of the resin are characterized by Fourier transform infrared spectroscopy to prove the rationality of the reaction mechanism. The cross-sectional morphology characteristics of the cured resin are observed by field-emission scanning electron microscopy. The results show that the closer the molar ratio of monomers in the reaction to the ratio of Fk0 of the reacting monomers, the better the polymerization performance.

Synthesis of three kinds of multi-armed cardanol-based acrylic resins based on different routes for UV/EB-cured coatings

In this work, we describe three kinds of multi-armed cardanol-based acrylic resins to fabricate UV/EB-cured coatings. Hydroxyethyl cardanol ether reacts with methyl etherified melamine formaldehyde resin to synthesize multi-arm cardanol-based oligomer (HF). HF was used to synthesize multi-arm cardanol-based epoxy acrylate (AEHF), cardanol acrylate (AHF), and cardanol-based polyurethane acrylate (ISHF) based on three different routes. The three synthetic routes were based on homogeneous catalytic system by peroxyacids through epoxidation and acrylate reactions, electrophilic addition reaction, and mercapto-olefin photo-click reaction. The structure and properties of AEHF, AHF, and ISHF were characterized by FR-IR, 1H-NMR and GPC. The three kinds of cardanol-based acrylic resins were used to prepare UV/EB-cured coatings, and the performance of the coatings was tested systematically. The hardness of AHF and ISHF coating has a high pencil hardness (3H), both adhesion of the three coatings can be improve to 0 grade after addition of phosphate resin. Compared with UV curing, EB-cured was not require photo-initiators, the storage modulus and the pencil hardness of the coatings were higher. The three kinds of cardanol-based acrylic resins can be applied in UV/EB-cured coatings for metal protection and other fields.

Reactive quaternary ammonium antimicrobial agent derived from cardanol for UV curable coating

The current research work presents an attempt to develop an antimicrobial agent from the bioresource cardanol which can be embedded in the polymer matrix to develop a UV curable coating. The brominated cardanol (BC) was synthesized from liquid bromine (Br2) and cardanol followed by the reaction with triethylamine (TEA) to synthesize quaternary ammonium cardanol (AC). Further, the reaction with glycidyl methacrylate (GMA) gives a UV curable antimicrobial agent (AA). This AA was incorporated in the epoxy acrylate UV curable system in various proportions along with the photoinitiator and coated onto a wooden substrate. The Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies and elemental analysis results revealed that the desired product has been formed. An antimicrobial test was performed with three types of microorganisms viz., bacteria, yeast, and fungi. The test results showed that the antimicrobial performance of the coatings was increased with the significant inhibition percentage values of 81.59% for gram-positive bacteria (Staphylococcus aureus), 77.12% for gram-negative bacteria (E. coli), and 73.82% for yeast (Candida albicans). Also, there was a decrease in the growth% value of the fungi (Aspergillus niger) as the concentration of AA in the system was increased. The mechanical properties of all the coatings were similar. There was a decrease in the Tg as well as in the degradation temperature of the coating films as the concentration of AA was increased, but the char yield got increased, as well. The sample with 20 wt% of AA showed the maximum amount of char yield (11.49%).

UV curable flame retardant coating: a novel synthetic approach of trispiperazido phosphate based reactive diluent

PurposeThe purpose of this work was to develop a new trispiperazido phosphate-based reactive diluent (diphosphate-piperazine hydroxyl acrylate [DPHA]) and used as a flame retardant with an epoxy acrylate (EA) in ultraviolet (UV)-curable wood coating.Design/methodology/approachThe concentration of reactive diluent was varied from 0% to 20% in the UV-curable formulation with constant photoinitiator concentration. The effect of DPHA concentration on film properties was studied by differential scanning calorimetry and thermogravimetric analysis, gel content, water absorption and limiting oxygen index.FindingsThe results showed that the viscosity of the prepared formulation decreased by increasing reactive diluent (DPHA) concentration which leads to improving the coating efficiency. A high concentration of reactive diluent (DPHA) of the cured films shows good resistance against stain, mechanical and thermal properties, which results in an increased glass transition temperature (Tg) and cross-linking density of the films.Originality/valueThe new trispiperazido phosphate-based reactive diluent was used in wood coating formulation, which resulted in excellent flame-retardant properties with higher cross-linked density with good stain resistance. This material can provide a wide range of application for coating industries to produce a glossy finish.

Synthesis of Mechanically Robust and Self-Healing UV-Curable Materials from Renewable Feedstock

Using renewable resources to synthesize a mechanically robust and self-healing UV-curable material is very important for the development of sustainable coatings. In this study, two kinds of UV-curable monomers synthesized from renewable feedstock, malic acid–glycidyl methacrylate (MG) and citric acid–glycidyl methacrylate (CG), were obtained under solvent-free conditions. As a result of high cross-linking density and abundant hydrogen bonds formed in networks, the cured MG and CG show high glass transition temperature, tensile strength, and modulus comparable to or better than those of the UV-curable material prepared from commercial bisphenol A epoxy acrylate (BPAEA). Meanwhile, taking advantage of −OH groups and the increase in ester concentration at elevated temperatures, the efficient self-healability of cured resins can be accomplished without an external catalyst through dynamic transesterifications. In this work, the cured MG and CG exhibit great potential in advanced coating applications, which introduces the first UV-curable materials with an integration of high mechanical performance and catalyst-free self-healing properties, obtained from bioresources.

Study on Properties of Waterborne Polyurethane Acrylate Modified Epoxy Acrylate Resin

Polyurethane acrylate modified epoxy acrylate resin with high solid content and great mechanical properties was synthesized by addition of polyethylene glycol in this work. The conversion process from liquid to solid was confirmed by comparing the FT-IR of oligomer and film. The disappearance of the carbon-carbon double bond absorption peaks at 1639 cm−1 and 819 cm−1 indicates that the oligomer is cured completely. In addition, the thermal analysis of the resin was characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). According to the experimental data, it can be seen from that the resin started to decompose at 293.31 until it is almost completely decomposed at 481.73°C which indicated that the stability of the film was better and the decomposition temperature was higher. In addition: Compared with the thermosetting resin E51 and the modified resin, the glass transition temperature is reduced by about 31 °C, which solves the problem of brittleness and hardness.