• Journal of the Korean Applied Science and Technology
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• v.33 no.4
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• pp.771-776
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• 2016

The acrylate copolymer having good thermal stability, coating and adhesion properties was designed and prepared. We prepared copolymers in >95% high yield using methyl methacrylate, isobornyl methacrylate and 2-hydroxyethyl methacrylate monomers by the bulk and emulsion polymerization techniques. The $^1H$-NMR spectrum was used to identify chemical structure and glass transition temperatures increased from $123^{\circ}C$ to $140^{\circ}C$ confirmed by DSC, DMA and TGA analysis. In addition, as the content of IBMA increased, storage modulus and thermal decomposition temperature increased. As the content of IBMA increased from 10% to 30% in the composition for the entire monomer, tensile strength increased from 22 to 30 MPa in both polymers prepared by bulk and emulsion techniques. The contact angle increased from 70 to up to 88 degrees due to hydrophobic property of IBMA.

• Polymer(Korea)
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• v.28 no.3
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• pp.273-280
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• 2004

Acrylic resins (ethyl methacrylate-2-hydroxypropyl methacrylate-n-butyl acrylate-acrylic acid EHBCs) containing 80％ of solid were synthesized. Then, high-solid coatings (ethyl methacrylate-2-hydroxypropyl methacrylate-n-butyl acrylate-acrylic acid/hexamethylene diisocyanate-biuret : EHBCNs) were prepared by curing of the acrylic resin with curing agent hexamethylene diisocyanate-biuret at room temperature. The cure time of prepared coatings EHBCN-4 (EHBC-4 : $T_{g}$ = $0^{\circ}C$) and EHBCN-7 (EHBC-7 : $T_{g}$ = 3$0^{\circ}C$), measured by rigid-body pendulum method, was recorded 6.2 hours and 4.5 hours, respectively. Dynamic viscoelastic experiment revealed the glass transition temperature of EHBCN-4 and EHBCN-7 to be $14^{\circ}C$ and $39^{\circ}C$, respectively. It was found that the adhesion and flexural properties among various properties of coatings were enhanced by the incorporation of caprolactone acrylate monomer into the acrylic resins.

• Applied Chemistry for Engineering
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• v.23 no.2
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• pp.157-163
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• 2012

Using six kinds of epoxy acrylates and a conductive carbon black, photosensitive resistor pastes were fabricated and then their developability in alkaline aqueous solution and the resistance values after thermal curing were evaluated. In order to impart the photocurability by UV exposure and the developability on alkaline solution, epoxy acrylate oligomers with carboxyl group, acrylate monomers, a photoinitiator and so forth were used. In addition, an organic peroxide was added into the paste to get a thermally curable composition. As a result, some of the pastes were not developed depending on the kinds of oligomers and, in the developed pastes, the measured resistance showed the different values depending on their compositions, even though they contain the same amount of carbon black. Finally, the optimum oligomer was selected and then, by adjusting the amount of carbon black, the kind of monomer and the curing temperature, the photosensitive resistor paste composition which showed the sheet resistance of about 0.5 $k{\Omega}/sq.$ could be obtained.

• Journal of Adhesion and Interface
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• v.15 no.1
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• pp.22-30
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• 2014

Self-photoinitiating acrylate (SPIA) which can undergo self-initiation under UV irradiation was synthesized by a Michael addition in the presence of a base catalyst. The SPIA polymerizations were investigated by photo-differential scanning calorimeter (photo-DSC) and surface physical properties such as pendulum hardness and pencil hardness. The results showed that the SPIA can cure upon UV irradiation by itself without a photoinitiator. But we found out that both the curing rate and the conversion were too low for the self-curing reaction of SPIA. In order to improve the SPIA curing properties, we introduced the SPIA/cationic hybrid system and observed the effects of the addition of commercial free radical type monomer and photoinitiator on the curing behaviors. SPIA/cationic hybrid system was the best suitable to improve the SPIA curing properties. The kinetic analysis indicated that the cationic monomer and photoinitiator apparently accelerated the cure reaction and rate of the hybrid SPIA system, mostly due to the synergistic effect of cationic monomer and photoinitiator increasing the mobility of active species and the generation of reactive species (free radical, cation) during the photopolymerization process. The physical properties showed that, unlike typical free radical system, the hybrid systems did not show oxygen inhibition effect because of cationic reaction on the coating surface.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.3
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• pp.224-228
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• 2012

We have developed new materials that lead to methyl meth acrylate monomer and styrene monomer to using polymerization method. The materials have a powder form and show liquid behavior. We call the "Electronic Bead". An our experiment, a positive-charged particle has $TiO_2$, polymer and CCA(-), while a negative-charged particle consists of carbon black, polymer and CCA(+). The charged particles have electrical characteristic of white -10 uC/g and black 10 uC/g, respectively. Also, these particles have good fluidity by additive of nano-sized silica. Using these materials, we demonstrated prototype displays that have $320{\times}320$ array of pixels and 6-in-diagonal viewable image size, driven by passive-matrix addressing. The reflectivity shows about 30% even though our experiment is at the beginning point. Also, the panel has contrast ratio 6:1. We think there are many chances to improve reflectivity through modifying components of particle resin, mixture ratio of each particle, panel structure and so on.

• Journal of the Korean Applied Science and Technology
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• v.21 no.2
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• pp.132-139
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• 2004

Film forming behavior of monodispersed model composite latexes with particle size of 190 nm, which consist of n-butyl acrylate as a soft phase monomer and methyl methacrylate as a hard phase monomer with different morphology was examined. Five different types of model latexes were used in this study such as random copolymer particle, soft-core/hard-shell particle, hard-core/soft-shell particle, gradient type particle, and mixed type particle. The film forming behavior was evaluated using pseudo on-line measurements of the cumulative weight loss, the UV transmittance, and the tensile fracture energy. Each stages of film formation I, II were not sensitive to the morphology of model latexes, but stage-ill was largely dependent on the morphology of model latexes. The chain mobility of polymer which composed the shell component was found to dominantly determine the behavior of film forming stage-III.

• Advances in nano research
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• v.12 no.4
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• pp.375-386
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• 2022

Synthesis of acrylate-based dispersion resins involves many parameters including temperature, ingredients concentrations, and rate of adding ingredients. Proper controlling of these parameters results in a uniform nano-size chain of polymer on one side and elimination of hazardous residual monomer on the other side. In this study, we aim to screen the process parameters via Internet of Things (IoT) to ensure that, first, the nano-size polymeric chains are in an acceptable range to acquire high adhesion property and second, the remaining hazardous substance concentration is under the minimum value for safety of public and personnel health. In this regard, a set of experiments is conducted to observe the influences of the process parameters on the size and dispersity of polymer chain and residual monomer concentration. The obtained dataset is further used to train an Adaptive Neural network Fuzzy Inference System (ANFIS) to achieve a model that predicts these two output parameters based on the input parameters. Finally, the ANFIS will return values to the automation system for further decisions on parameter adjustment or halting the process to preserve the health of the personnel and final product consumers as well.

• Korean Journal of Materials Research
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• v.30 no.6
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• pp.273-278
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• 2020

This research is conducted to analyze the compatibility of used monomers and produce the high functional hydrogel ophthalmic polymer containing silane and nanoparticles. VTMS (vinyltrimethoxysilane), TAVS [Triacetoxy(vinyl)silane] and cobalt oxide nanoparticles are used as additives for the basic combination of SilM (silicone monomer), MMA (methyl methacrylate) and MA (methyl acrylate). Also, the materials are copolymerized with EGDMA (ethylene glycol dimethacrylate) as cross-linking agent, AIBN (thermal polymerization initiator) as the initiator. It is judged that the lenses of all combinations are optically excellent and thus have good compatibility. Measurement of the optical and physical characteristics of the manufactured hydrophilic ophthalmic polymer are different in each case. Especially for TAVS, the addition of cobalt oxide nanoparticles increases the oxygen permeability. These materials are considered to create synergy, so they can be used in functional hydrogel ophthalmic lenses.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1204-1207
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• 2004

The effects of surfactant on the electro-optic properties of holographic polymer dispersed liquid crystal(HPDLC) have been studied hoping to increase the diffraction efficiency and to reduce the anchoring energy at interfaces. Octanoic acid(OA) was used as sulfactant. The 2,2,2 trifluoroethyl acrylate(TFEA) was added to the monomer mixture to enhance the phase separation and improve optical properties. The morphology of holographic gratings was examined using scanning electron microscopy(SEM). Addition of surfactant was likely to reduce the surface anchoring of the nematic droplet with the polymer surface which favors lowering of the swiching field and to improve the optical qualities.

• Journal of the Korean Applied Science and Technology
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• v.25 no.1
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• pp.83-90
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• 2008

The core-shell latex particles were prepared by sequential emulsion polymerization using alkyl methacrylate as a shell monomer and potassium persulfate (KPS) as an initiator. We study the effects of core-shell structure of calcium carbonate/alkyl methacrlyate in the presence of an anionic surfactant sodium lauryl sulfate (SLS) and polyoxyethylene alkyl ether sulfate (EU-S133D)). The structure of core-shell polymer were investigated by measuring to the thermal decomposition of polymer composite using thermogravimetric analyzer and morphology of latex by transmission electron microscope (TEM).