• Korean Journal of Materials Research
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• v.27 no.4
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• pp.199-205
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• 2017

In this study, (3,4-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate acrylate was synthesized by reacting (3,4-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate with acrylic acid to minimize hardening shrinkage and to improve heat resistance, which are known as disadvantages of photopolymers for 3D printing application. Urethane acrylate was synthesized by reacting 1,3,5-triazine-2,4,6-triamino alcohol, 2-hexylethyl acrylate, and isophorone diisocyanate in order to improve the mechanical properties without deteriorating the heat resistance. The physical properties before and after the synthesis of the acrylate and the mechanical properties when the urethane acrylate was applied were investigated. The reaction progress of the composite was examined by FTIR and $^{13}C$ NMR. The heat deflection temperature, flexural strength, and surface hardness of the molding were measured. The curing behavior by Photo-DSC ultraviolet irradiation was also examined.

• Polymer(Korea)
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• v.38 no.2
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• pp.138-143
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• 2014

${\alpha},{\omega}$-Hydroxypropyl polydimethylsiloxane (HO-PDMS) was prepared by hydrosilylation of hydrogen terminated polydimethylsiloxane with allyl alcohol. Polydimethylsiloxane modified urethane with isocyanate group (PSU) was prepared from cyclic trimer of hexamethylenediisocyanate with HO-PDMS. PDMS modified urethane base resin with acrylic group (PSUA) was prepared from the urethane reaction of PSU with isocyanate group and 2-hydroxyethylmethacrylate. Their structures were characterized using FTIR and NMR. Coating materials were prepared by mixing PSUA, acrylic hardner, photo-initiator, and solvent and coated on PET film to obtain flexible and hard coating film by UV irradiation. Transparency of coating film was 89.7%, contact angle, $88^{\circ}$, and pencil hardness, 3H.

• Elastomers and Composites
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• v.48 no.4
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• pp.249-255
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• 2013

Hydroxypropyl terminated PDMS was synthesized by the hydrosilylation reaction with allyl alcohol in the presence of Karstedt's catalyst. And them, an one-pot reaction with HDI isocyanurate trimer and hydroxyethyl methacrylate was conducted to give a silicone-modified urethane acrylate oligomer (PUA oligomer) having 9000 g/mol, weight average molecular weight. The synthesized PUA oligomer was characterized by using FT-IR and GPC. The UV-curable coatings were prepared by PUA oligomer blending with a reactive monomer (phenylthioethyl acrylate) under the different mole ratios. It was found that the refractive index of cured film increased when the reactive monomer was added but there was no relationship between the refractive index and amount of reactive monomer. Also, their transmittance for cured films was not change as increasing the content of reactive monomer.

• Journal of Adhesion and Interface
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• v.22 no.3
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• pp.98-105
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• 2021

In this study, we prepared a silver nanoparticle transferable adhesive composition with transparency and adhesive properties using UV-curable urethane acrylate containing silane groups. The urethane-based adhesive composition was applied between the Ag/PET film in which silver nanoparticles were patterned on PET and the PC film to be transferred. Immediately after UV-curing with UV, PET was removed to complete the manufacture of Ag/PC film. UV-curable urethane acrylate containing silane groups was synthesized using polycaprolactone diol (PCL), isophrone diisocyanate (IPDI), 2-hydroxyethyl methacrylate (HEMA), and (3-aminopropyl) triethoxysilane (APTES). The silane group of APTES can improve interfacial adhesion by reacting with the specially treated silver nanoparticle surface of the Ag/PET film. In addition, we improved the adhesion between silver nanoparticle and PC film by mixing UV-curable urethane acrylate containing a silane group and a functional acrylic diluent used as a diluent. We analyzed the synthesis process of urethane acrylate using FT-IR, and compared the adhesive properties, optical properties, and transfer properties according to the molar ratio of APTES and the acrylic diluent composition. As a result, the best transfer properties were confirmed in the adhesive composition prepared under the conditions of PUA2S1_0.5.

• Polymer(Korea)
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• v.38 no.1
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• pp.1-8
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• 2014

The effects of surface color and morphology on the mar behaviors of urethane-acrylate coated surfaces were examined. The superiority of mar resistance was observed in the order of white, red and black-colored samples. This can be explained by a contrast effect. In other words, in case of black colored sample, it takes place the defuse reflection of the incident light on the damaged region where mar damage exerts, leading to whitening phenomenon. Therefore, the damaged region is easily recognized by contrasting the black background. On the other hand, it is difficult for the white-colored sample to perceive the mar-damaged area by the white background acting as protecting coloration. As the gloss of urethane-acrylate coated surface increases, it is observed that there is an increase in the number of carbonyl (-C=O) function group, amount of ethylene and silica. The enhancements of surface rigidity by adding the silica particles and formation of carbonyl function groups by the surface oxidation lead to the increase in mar resistance, while the increase of polyethylene wax is responsible for the improved gloss and smooth-faced surface. Based on the above findings, technical approaches leading the improvement of mar resistance of the urethane-acrylate coated surface are discussed.

• Journal of Adhesion and Interface
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• v.18 no.4
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• pp.159-165
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• 2017

In this study, we synthesized UV-curable urethane acrylates with different contents of BA, reactive diluent and characterized their physical properties such as thermal, mechanical properties, adhesive strength and flexibility resistance. From a result of DSC, Tg of polyol and acrylate resin were separated as the BA content increased more than 40%. Also, tensile strength, elongation and adhesive strength decreased with increasing the BA content. The UV-curable urethane acrylate with 40% BA has shown good flexibility resistance compared to other resin due to poor hardness and Tm of acrylate resin.

• Applied Chemistry for Engineering
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• v.17 no.1
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• pp.33-36
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• 2006

The kinetics of photopolymerization of urethane-acrylate oligomer which has many applications in photopolymerizable adhesives was analysed to investigate the influence of polymerization temperature and functionality of oligomer using the autocatalytic model. It was revealed that the maximum polymerization rate decreased as the polymerization temperature increased. The reaction rate constant, k, showed little change with the increase in polymerization temperature, while exponents m and n exhibited an increase. These results could be related to the diffusion and mobility restriction of reactive species during the cross-linking reaction. The decrease in photopolymerization rate with increase of temperature was mainly controlled by the reaction order n.

• Journal of the Semiconductor & Display Technology
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• v.16 no.3
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• pp.87-92
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• 2017

Poly(urethane acrylate) siloxane oligomers with Interpenetrating polymer networked nanoparticles were prepared to synthesize hard coating solution by reaction with isophorone diisocyanate(IPDI) of 1, 2, 3, 4 phr. The structures and molecular weights of the synthesized solutions were characterized by IR spectroscopy and gel permeation chromatography, respectively. In the cross-cut test for the adhesion, all the solutions showed good adhesion of 5B regardless of the content of IPDI and film thickness. The addition of 1 phr IPDI resulted in the best pencil hardness. The IPDI combined siloxane hard coating solution showed more flexibility than the siloxane solution. These results will yield the improvement in the siloxane solution using for plastic display plate.

• Polymer(Korea)
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• v.35 no.2
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• pp.183-188
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• 2011

Pentaerytritol triacrylate (PETA) was synthesized by a condensation reaction between pentaerytritol and acrylic acid. The highest yield of PETA was obtained when heptane was used as a solvent under the 1:4 mole ratio of pentaerytritol and acrylic acid. The 6-functional urethane acrylates(UA) were also synthesized by a condensation reaction between PETA and diisocyanate. Cured films were prepared from the mixtures of UA oligomer, reactive diluents and UV initiator to investigate their physical properties. The thermal stability of the aliphatic urethane acrylate was better than that of the aromatic urethane acrylate. The UA-2 showed good hardness and scratch resistance properties while the UA-l with a high degree of curing density exhibited a better chemical resistance. All the UA oligomers showed fairly good adhesion strengths but the other physical properties of UA-3 were poor due to its low curing density.

• Journal of the Korean Wood Science and Technology
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• v.27 no.3
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• pp.31-38
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• 1999

This paper deals with a coating technique of hardening surface layer of softwood{Larix leptolepis) flooring board to improve its surface properties such as hardness and abrasion resisitance without spoiling its exellent qualities such as beautiful color tones and great strength. For surface hardening of the wood, polyurethane wood sealer was used as under coat, polyurethane sanding sealer as intermediate coat, and UV-curing epoxy acrylate and urethane acrylate varnishes as top coat. The hardness of the wood was improved by the coating treatment and it was similar to that of high density hardwood such as oak, keruing. The abrasion resistance of the coated wood was greatly improved by UV curing epoxy acrylate or urethane acrylate varnishes. Adhesion properties and impact resisitance of the coated wood surface were also good. It was suggested that the well-coated larch wood could be used as interior flooring board as substitute for hardwood such as keruing.