• Macromolecular Research
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• 제9권2호
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• pp.122-128
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• 2001

Monodisperse composite latex particles with size of ca. 300 nm, which consist ofn-butyl acrylate as a soft phase and methyl methacrylate as a hard phase with different morphology, were synthesized by seeded multi-stage emulsion polymerization. Three types of composite latex particles including random-, core/shell-, and gradient-type particles were obtained by using different monomer feeding methods during semi-batch emulsion polymerization. Effect of poly(butyl acrylate)-poly(methyl methacrylate) rubber particle morphology on the mechanical and rheological properties of rubber toughened poly(methyl methacrylate) was investigated. Among three different rubber particles, the gradient-type rubber particle showed better toughening effect than others. No significant variation of rheological property of poly(methyl methacrylate)/rubber blends was observed for the different rubber particle morphology.

• 폴리머
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• 제39권2호
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• pp.329-337
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• 2015

본 연구에서는 다중벽 탄소나노튜브(MWCNTs)를 질산과 황산의 혼산으로 산화시켜 표면에 카르복시기를 도입 후, $SOCl_2$와 1,4-butanediol을 사용하여 MWCNT-OH를 제조하였다. 제조된 MWCNT-OH는 3-methacryloxypropyltrimethoxylsilane(MPTMS)와 실란화 반응으로 methacrylate기가 도입된 MWCNT-MPTMS를 제조하였다. MWCNT-MPTMS와 methyl methacrylate(MMA)를 사용하여 유화중합법으로 MWCNT-MPTMS/PMMA 복합 입자를 제조하였다. 음이온 계면 활성제인 sodium dodecylbenzene sulfonate(SDBS)를 사용하여 유화중합한 MWCNT-MPTMS/PMMA는 균일한 입도, 좁은 입도분포 및 계면에서의 화학결합으로 인하여 $T_g$가 순수 MWCNT를 사용하여 중합한 시료보다 $3.4^{\circ}C$ 높아짐을 확인하였다.

• Elastomers and Composites
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• 제52권4호
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• pp.272-279
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• 2017

The heterocoagulation of latex is a simple and useful method to fabricate various polymer nanocomposites in which a precise control of the colloid stability is essential. In this work, a multi-layered graphenes (MLGs)/poly(styrene-co-butyl acrylate) (P(S-co-BA)) nanocomposite having an excellent dispersion of MLGs was prepared via the sudden heating heterocoagulation process. The P(S-co-BA) component was obtained by emulsion polymerization. This process can effectively shorten the process and particles growth steps. The colloid stability of these dispersions was controlled by factors such as ionic charge, temperature, and reaction times. The influence of these factors on heterocoagulation was evaluated and the properties of the nanocomposites were investigated. The conductivity of the MLGs/P(S-co-BA) nanocomposites increased from -11.53 to -5.70 S/cm for an increase in MLG content from 0.01 to 5 wt%. Moreover, percolation threshold was observed in the case of 0.01 wt% MLGs.

• Macromolecular Research
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• 제15권6호
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• pp.498-505
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• 2007

This study demonstrated the in-situ functionalization with polymers of multi-walled carbon nanotubes (MWNTs) via emulsion polymerization. Polystyrene-functionalized MWNTs were prepared in an aqueous solution containing styrene monomer, non-ionic surfactant and a cationic coupling agent ([2-(methacryloyloxy)ethyl]trime-thylammonium chloride (MATMAC)). This process produced an interesting morphology in which the MWNTs, consisting of bead-string shapes or MWNTs embedded in the beads, when polymer beads were sufficiently large, produced nanohybrid material. This morphology was attributed to the interaction between the cationic coupling agent and the nanotube surface which induced polymerization within the hemimicellar or hemicylindrical structures of surfactant micelles on the surface of the nanotubes. In a solution containing MATMAC alone without surfactant, carbon nanotubes (CNTs) were not well-dispersed, and in a solution containing only surfactant without MATMAC, polymeric beads were synthesized in isolation from CNTs and continued to exist separately. The incorporation of MATMAC and surfactant together enabled large amounts of CNTs (> 0.05 wt%) to be well-dispersed in water and very effectively encapsulated by polymer chains. This method could be applied to other well-dispersed CNT solutions containing amphiphilic molecules, regardless of the type (i.e., anionic, cationic or nonionic). In this way, the solubility and dispersion of nanotubes could be increased in a solvent or polymer matrix. By enhancing the interfacial adhesion, this method might also contribute to the improved dispersion of nanotubes in a polymer matrix and thus the creation of superior polymer nanocomposites.

• 한국건축시공학회지
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• 제3권1호
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• pp.93-105
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• 2003

The Precast Concrete(PC) method was developed for a large production of a structure in Europe. Afterwards, this PC method has been applied to a structure and an outside Coating of buildings extensively. The outside Coating of the building applied this PC method is a method to put tiles or stones to base concrete. And there is a method to use paints for, so the expression of various patterns is possible. The Multi-Layer Coating is one of the methods to use paints. This Multi-Layer Coating method can show various designs of external appearance with Foam when it is made with the PC panel. Also, the paint film of the PC panel enables a splendid appearance, and a protective function of concrete is possible, too. Therefore, it makes good durability of the PC. Besides, maintenance is easy to manage because it is free from pollution when it uses metallic materials, stones, or any other materials. You might have no trouble in applying the Multi-Layer Coating method in order to save a merit of an outside Coating on the PC panel. However, the Multi-Layer Coating method used as a current outside Coating method has pollution and bad working environment because Oil Epoxy Resins have toxicity and flammability. Therefore, a lot of warnings are required for coating work in order to have appropriate quality because working hours are short, and production efficiency is low too. These reasons make the cost of construction of the Multi-Layer Coating method increase. And employers or designers may have problems in selecting this Multi-Layer Coating method. Therefore, the purpose of this study is to get activation of the Multi-Layer Coating method by offering improvement measures about the problems of the existing Multi-Layer Coating method.

• KSBB Journal
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• 제24권5호
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• pp.477-482
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• 2009

본 연구는 포도가공부산물로부터 유용성분을 추출하여 자원의 활용과 환경오염을 줄이고, 공정을 간결하게 하여 실제산업현장에서 이용할 수 있는 공정의 개발을 목적으로 하였다. 포도가공 부산물을 포도과피와 포도씨로 나누어 과피에서는 anthocyanin을 씨에서는 oligomeric proanthocyanidin (OPC)를 주 대상물질로 하여 추출하기 위한 공정을 개발하였다. 추출된 항산화물질은 HPLC를 이용하여 정량하였으며, 이들의 효능은 DPPH법, SOD법을 이용하여 대조군들과의 비교를 통하여 확인하였다. 두 방법 모두 포도씨 추출물의 효능이 포도과피 추출물보다 뛰어난 항산화도를 보였다. 이렇게 생산된 추출물을 이용하여 multiple lamella emulsion의 화장품 제형을 개발하였고 이 제형의 안전성과 안정성을 실험적으로 확인하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
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• pp.261-267
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• 2004

Current steel makers are trying to develop new manufacturing process to secure price competition and to improve productivity by testing a various kinds of rolling condition of several kinds of steel at TCM. Accordingly, Reverse Mill operation for Stainless steel is changing to TCM operation and furthermore, even general carbon steel and electric steel plate are requested to be worked at TCM simultaneously. By these changing of rolling condition, it become to be necessary to develop new water-soluble cold rolling oil that has a characteristics to be suitable for various working condition and in this report, we would like to mention lubrication condition to fulfill requested characteristics of each steels and development and applying result of multi-purpose water-soluble cold rolling oil which has such an lubrication property.

• 접착 및 계면
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• 제14권1호
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• pp.1-12
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• 2013

Core 입자로 methyl methacrylate (MMA), ethyl methacrylate (EMA)를 사용하고 shell 입자로 MMA, EMA, 2-hydroxyl ethyl methacrylate (2-HEMA), glycidyl methacrylate (GMA) 및 methacrylic acid (MAA)를 각각 사용하여 개시제 ammonium persulfate (APS), 유화제로 sodium dodecyl benzene sulfonate (SDBS)의 농도(0.01~0.03 wt%), 단량체의 종류와 조성을 변화시켜 수용성 유화중합으로 다중 core-shell복합입자를 제조하여 전환율, 입자경 및 입도분포, 평균분자량, 분자구조, 유리전이온도, 플라즈마 처리후의 접촉각, 등온열분해속도 및 인장강도를 각각 측정하여 다음과 같은 결론을 얻었다. SDBS 농도 0.02 wt%에서 MMA core-(EMA/GMA) shell 복합입자의 전환율이 98.5%로 우수하였고, 입자직경은 SDBS 농도 0.03 wt%에서 EMA core-(MMA/GMA) shell의 복합입자가 $0.48{\mu}m$로 높게 나왔다. 유리전이온도 측정으로부터 공중합체는 1~2개의 전이곡선 그리고 다중 core-shell 복합입자는 3개의 전이곡선을 얻었다. 전체적으로 접착박리강도의 크기는 shell 단량체가 MMA core인 경우 EMA/MAA > EMA/2-HEMA > EMA/GMA의 순으로 되었다.

• 접착 및 계면
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• 제12권1호
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• pp.16-25
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• 2011

Core 입자로 methyl methacrylate (MMA), n-butyl methacrylate (BMA)를 하고 shell 입자로 MMA, BMA, stylene (St), 2-hydroxylethylmethacrylate (2-HEMA), acrylic acid (AA)를 각각 사용하여 개시제 aommonium persulfate (APS), 유화제로 sodium dodecyl benzene sulfonate (SDBS)의 농도(0.01~0.03 wt%), 단량체의 종류와 조성을 변화시켜 수용성 유화중합으로 다중 core-shell 복합입자를 제조하여 전화율, 입자경 및 입도 분포, 평균 분자량, 분자구조, 유리전이온도, 입자의 형태 및 인장강도와 신율을 각각 측정하여 다음과 같은 결론을 얻었다. SDBS 농도 0.02 wt%에서 MMA core-(BMA/St/AA) shell 복합인자가 전화율이 98%로 우수하였고, 입자 직경은 SDBS 농도 0.03 wt%에서 BMA core-(MMA/St/AA) shell의 복합입자가 $0.47{\mu}m$로 높게 나왔다. 유리전이온도 측정은 단일 core-shell 복합입자의 2군데에 비하여 다중 core-shell 복합입자는 3군데가 존재하여 shell단량체 내의 단량체의 종류와 조성에 따라 유리전이온도 조절도 가능하고 동시에 접착력이 향상된 접착소재로서 부직포 섬유 결속제로 사용될 수 있었다.

• 한국유체기계학회 논문집
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• 제11권5호
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• pp.50-56
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• 2008

Metal cutting operations involve generation of heat due to friction between the tool and the pieces. This heat needs to be carried away otherwise it creates white spots. To reduce this abnormal heat cutting fluid is used. Cutting fluid also has an important role in the lubrication of the cutting edges of machine tools and the pieces they are shaping, and in sluicing away the resulting swarf. As a cutting fluid, water is a great conductor of heat but is not stable at high temperatures, so to improve stability an emulsion type mixed fluid with water and oil is often used. It is pumped over the cutting site of cutting machines as a state of atomized water droplet coated with oil by using jet. In this paper, to develop cutting fluid supplying nozzle to obtain ultra thin oil film for coating water droplet, a numerical analysis of three dimensional mixed fluid Jet through multi-stage nozzle was carried out by using a finite volume method. Jet flow characteristics such as nozzle exit velocity, development of mixing region, re-entrance and jet intensity were analyzed. Detailed mixing process of fluids such as air, water and oil in the nozzle were also investigated. It is easy to understand complex flow pattern in multi-stage nozzle. Important flow Information for advance design of cutting fluid supplying nozzle was drawn.