• Polymer(Korea)
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• v.34 no.1
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• pp.38-44
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• 2010

Core-shell particles of inorganic/organic pair were synthesized from $CaCO_3$ absorbed sodium dodecyl benzene sulfonate(SDBS) surfactant. Shell components were synthesized by sequential emulsion polymerization. Various monomers were used as shell components such as methyl methacrylate(MMA), ethyl acrylate(EA), butyl acrylate(BA), and styrene(St). Ammonium persulfate(APS) was used as an initiator and 2-ethylhexyl acylate(2-EHA) was used as a functional monomer, In the $CaCO_3$/organic core-shell particle polymerization, $CaCO_3$ absorbed surfactant SDBS of 0.5 wt% was prepared first and then core $CaCO_3$ was encapsulated by emulsion polymerization. 0.1 wt% of APS was added sequentially to minimize the formation of new monomer particle during shell polymerization. The structure of inorganic/organic core-shell particles were characterized by measuring the decomposition degree of $CaCO_3$ using HCl solution, thermogravimetric analyzer, scanning electron microscope, and transmission electron microscope.

• Journal of Adhesion and Interface
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• v.20 no.4
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• pp.135-139
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• 2019

In this work, flame retardant acrylic emulsion pressure sensitive adhesives were newly polymerized combining phosphorous flame retardant monomer and acrylic monomer like butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, acrylic acid, and 2-hydroxyethyl methacrylate. The process of polymerization showed 100% of conversion at solid content of 65%, and viscosity of acrylic emulsion was increased up to 5500 cps when phosphorous flame retardant monomer was added into acrylic emulsion. The structure of flame retardant acrylic emulsion was identified using FT-IR and thermal properties like glass transition temperature (Tg) were checked by differential scanning calorimeter (DSC). Acrylic emulsion without phosphorous flame retardant monomer had Tg of -44.1℃ and peel strength of 2,100gf/inch, however, flame retardant acrylic emulsion showed maximum Tg (-31.4℃) and peel strength of 200gf/inch when 15 part of phosphorous flame retardant monomer was added. Flammability test was also conducted to confirm the application of flame retardant acrylic emulsion as the flame retardant addtive.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.632-638
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• 2012

Waterborne polyurethane dispersions (PUD) were synthesized from isophorone diisocyanate (IPDI), polycarbonate diol (PCD) and dimethylol propionic acid (DMPA) as starting materials. Subsequently, waterborne polyurethane-acrylic hybrid solutions were prepared by reacting the PUD with different amounts of the mixture of acrylate monomers, HEMA (2-hydroxyethyl methacrylate) and MMA (methyl methacrylate). As a result, the average particle size of waterborne polyurethane-acrylic hybrid solutions was increased with increasing the addition amounts of acrylate monomers. Also, the prepared coating films from waterborne polyurethane-acrylic hybrid solutions showed better abrasion resistance and chemical resistance than those of pure PUD.

• Proceedings of the KAIS Fall Conference
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• 2004.11a
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• pp.265-268
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• 2004

Methyl methacrlate와 cyclopentadiene을 반응하여 Methyl 5-methylbicyclo(2.2.1)hept-2-ene-5-carboxylate(MMBHC)를 합성코자 하였다. 합성된 MMBHC의 온도, solvent 변화와 촉매($AlCl_3$)의 사용 유무에 따른 endo, exe의 비율을 관찰하였다. 온도가 낮은 경우 온도가 높은 쪽 보다 endo 비율이 높았고 촉매($AlCl_3$)를 사용하였을 때(약 endo : exo = 63 : 37) 촉매를 사용하지 않은 반응(endo : exe = 34 : 66)보다 endo의 비율이 높았다. methyl acrylate를 사용한 경우 같은 조건에서 endo : exe의 비율이 93.5 : 6.5로 MMA를 사용한 경우보다 endo의 비율은 좋았다. 온도가 높은 경우 수율은 좋았지만 exe의 비율이 높았고 solvent에 따라 endo, exe의 선택도는 큰 차이를 보이지 않음을 알 수 있었다.

• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.769-772
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• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1267-1268
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• 2010

• Polymer(Korea)
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• v.34 no.3
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• pp.247-252
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• 2010

This paper investigates the effects of the monomer ratios on the typical properties of polymer-modified mortars that contain methyl methacrylate-based latexes. Basic data are also obtained to develop appropriate latexes for cement modifiers. Polymer-modified mortars that contain methyl methacrylate latexes copolymerized with butyl acrylate or ethyl acrylate are prepared for different polymer-cement ratios. They are then tested to obtain the tensile and tensile adhesive strengthes of polymer-modified mortar with methyl methacrylate-based latexes. From the test results, the tensile strength of MB7 polymer-modified mortar was higher than normal cement mortar by a maximum of 94% with a 20% polymer-cement ratio, which was almost twice higher than normal. The tensile adhesive strength of the MB polymer-modified mortar was higher for higher MMA monomer contents and polymer-cement ratios, and increased up to four times than that of normal cement mortar. The basic properties of the polymer-modified mortars are more affected by the polymer-cement ratio than by the monomer ratio, and are improved over unmodified mortar.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.12
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• pp.1871-1876
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• 2004

We demonstrate a novel fabrication technology for the microneedle array that can be used in the medical test field, which is transdermal drug delivery and blood analyte sampling. Previous researchers have used silicon-processed micromachining, a reactive ion etching, and molding techniques for the fabrication of microneedle array. However, these fabrication techniques have somewhat limitations apply to the microneedle array fabrication according to its application. Inclined LIGA process is suggested to overcome these problems. This process provides easier, sharper and longer out-of-plane microneedle array structure than conventional silicon-processed fabrication method did. Additionally, because of the advantage of the LIGA process based on mold fabrication for mass production, the polymer, PMMA(PolyMethylMethAcrylate), based microneedle array is useful as the mold base of nickel electroplating process; on the other hand, silicon-processed microneedle array is used in itself. In this research, we fabricate different types of out-of-plane microneedle array, which have different shape of tip, base and hole structure, using the inclined LIGA process. The fabricated microneedles have proper mechanical strength, height and sharpness to puncture human hand epidermis or dermis with less pain and without needle tip break during penetrating the skin.

• Journal of the Korean Chemical Society
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• v.58 no.3
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• pp.251-257
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• 2014

The stress relaxation of poly(methyl acrylate)-poly(acrylonitrile) copolymer samples were carried out in air and distilled water at various temperatures using the tensile tester with the solvent chamber. The rheological parameters were obtained by applying the experimental stress relaxation curves to the theoretical equation of the Eyring-Halsey non-Newtonian model. The self diffusion, hole volume, viscosities, and thermodynamic parameters of copolymer samples were calculated from rheological parameters and crystallite size in order to study of flow segments in amorphous region. It was observed that the rheological parameters of these copolymer samples are directly related to the self diffusion, hole volume, viscosities, and thermodynamic parameters of flow segments.

• Journal of Adhesion and Interface
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• v.5 no.4
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• pp.1-8
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• 2004

UV-curable pressure sensitive adhesives were prepared by blending acrylic copolymer, copolymerized with butyl acrylate, acrylic acid and methyl methacrylate by solution polymerization, and trimethylolpropane triacrylate. The PSAs were evaluated by adhesion strength with varying UV dose, and also glass transition temperature ($T_g$) of PSAs were measured. When exposed on UV irradiation, the PSAs showed the decreased adhesion strength and increased $T_g$. And following UV irradiation, the PSAs did not leave any residue on wafer after peel off PSA.