• 반도체디스플레이기술학회지
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• 제13권3호
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• pp.51-55
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• 2014

Ni-CNT(Carbon Nanotubes) composite coating is often used for the surface treatment of mechanical/electronic devices to improve the properties of the Ni coating. For the Ni-CNT coating, the dispersion of CNT fibers is a critical process. In this study, ultrasonic treatment instead of the conventional ball milling was attempted as a dispersion method for the electroless Ni-CNT coating. SEM-EDX analysis was performed and contact angle, sheet resistance, and micro-hardness were measured. Results showed that the ultrasonic treatment was comparable to the ball milling, as a dispersion method, but the difference was negligible. However, combined ball milling and ultrasonic treatment(double treatment) showed much improved micro-hardness value, above 350Hv(close to the value obtained by the Ni-CNT electroplating). In addition, electroless Ni-CNT(double-treated) coatings formed on the thin Ni film deposited by the electroless plating(double coating) showed better mechanical properties. Thus, double treatment and double coating are suggested as an improved electroless Ni-CNT coating method.

• Corrosion Science and Technology
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• 제14권5호
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• pp.207-212
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• 2015

The purpose of this research was to synthesize fluorine modified waterborne polyurethane dispersion (F-WPU) by soap-free (internal emulsifier) emulsion polymerization techniques, to prepare coating solution based on fluorine modified waterborne polyurethane dispersion (F-WPU) and to compare the chemical and thermo-mechanical properties on the electrogalvanized steel sheet. Environmentally friendly F-WPU was prepared with a fluorinated polyol containing 60 wt% of fluorine. There are various ways of combining a wide variety of fluorinated polyols and diisocyanate to exhibit novel properties of waterborne polyurethane dispersion. Components of coating solution were largely divided into 4 kinds i.e., F-WPU, acrylic emulsion, silane coupling agent, and colloidal silicate. F-WPU coating solution on the electro-galvanized steel sheet showed excellent properties of corrosion resistance, alkali resistance and heat resistance, as compared to other coating solutions using a general waterborne resin. The F-WPU coating solution's reliable effects are possibly due to the fluorine atoms incorporated even in a small amount of F-WPU.

• 한국세라믹학회지
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• 제48권6호
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• pp.537-542
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• 2011

Magnesium hydroxide as a non-halogen flame retardant has increasing attention due to its non-toxicity, high decomposition temperature and smoke suppressant ability during combustion. For the application of magnesium hydroxide retardant to the textile by soaking and coating method, the prerequisite for the coating is a small particle size, stable dispersion, and adhesion to the textile. The dispersion of $Mg(OH)_2$ particles and stability of the coating was checked by monitoring the change of transmittance and backscattering by varying the types of dispersion agents, binder, solvent, and $Mg(OH)_2$ source, and their compositions in the coating. The $Mg(OH)_2$ dispersion coating was applied to PET(poly(ethylene terephthalate)) non-woven textile. The physical properties are characterized by surface morphology, amount of coating, particle dispersion, and adhesion test. The flame retardant $Mg(OH)_2$ coated textile has been compared by limited oxygen index(LOI) and thermal gravimetry and differential scanning calorimetry(TG-DSC). It was found that phosphorous additive may give synergistic effect on $Mg(OH)_2$ flame retardant coating to make the flame retardant PET non-woven textile.

• Korean Chemical Engineering Research
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• 제51권1호
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• pp.73-79
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• 2013

Polycarbonate diol (PCD), isophorone diisocyanate (IPDI)와 dimethylol propionic acid (DMPA)를 출발물질로 하여 수분산 폴리우레탄(waterborne polyurethane dispersion, WPUD)을 합성하였다. WPUD에 아크릴 단량체인 methyl methacrylate (MMA)를 첨가하여 수분산 아크릴 폴리우레탄(waterborne acrylic polyurethane dispersion, AUD)을 합성하였다. 이 AUD와 물에 분산되어 있는 multi-walled carbon nanotube (MWCNT)를 혼합하여 전도성 코팅 용액을 제조한 후 polycarbonate 시트 위에 도포하여 코팅 도막을 형성하였다. AUD 중의 MMA의 첨가량이 증가될수록 코팅 도막의 연필경도, 내마모성 및 내약품성은 향상되었으나 전기 전도도는 감소하였다. 반면에 전도성 코팅 용액 중의 MWCNT의 첨가량이 증가될수록 코팅 도막의 연필경도, 내마모성 및 내약품성은 감소되었으나 전기 전도도는 증가하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.279-279
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• 2013

We report on the preparation of polydimethylsiloxane (PDMS) coated multi-walled carbon nanotubes (MWNTs) followed by their dispersion in various solvents. To disperse MWNTs without acids of surfactants, which are the commonly used methods, hydrophobic PDMS coating was selected. It was determined that the PDMS coated MWNTs are more dispersed in diverse solvents such as dimethyl formamide (DMF) and acetone than bare MWNTs. In case of DMF solvent, dispersion of MWNT was improved by 40 % upon PDMS-coating of MWNT, which was confirmed by UV/Vis absorption spectroscopy. In this work, the PDMS coated MWNTs dispersed solution was also used for the fabrication of film, which is conductive, transparent and superhydrophobic because of the reduced aggregation and increased water repellency of MWNTs.

• 한국응용과학기술학회지
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• 제10권1호
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• pp.49-55
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• 1993

Ground Calcium Carbonate, among paper coating pigments, will influence less dispersant demand, less binder demand, increase coating solids from 58% to 70%, which means high speed coating, less shrinkage during drying, less energy consumption, more uniform coverage of fibers. The quality point of view of Ground Calcium Carbonate, brightness, particle size, Particle size distribution, hardness, impurities content are important. More important factors of Ground Calcium Carbonate which influence the paper coating process are dispersion mechanisms and their effects. The study was made to investigate the effect of Ground Calcium Carbonate dispersion by sodium salt of polyacrylate dispersant composition and dispersion condition. Basic tests such as physical, optical and chemical were perfumed, and dispersion effects were investigated by different conditions. The results showed that the type of dispersant affected the dispersion effects, and the Ground Calcium Carbonate has critical dispersant demand.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2016년도 추계학술대회 논문집
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• pp.136-136
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• 2016

Commonly used oil-based polymer resin has environmental and safety issues. Many researches for replacing the harmful solvent-borne resins to water-borne resins have been investigated to purify harmful environmental resources and follow the export and import of hazardous materials regulations. In this research, ultrasonic spray coatings of aqueous polymer resin were studied to fabricate thin insulating layer (${\sim}{\mu}m$) on the rectangular copper wire. It needs to have appropriate wettability between resin and substrate during the ultrasonic spray coating process to coat aqueous polymer uniformly. Furthermore, stabilities of coating solution and fabricating process are required to form thin insulating layer on the substrate. In here, physical characteristics such as viscosity of 6 types of commercial polymer dispersions and emersions were analyzed to confirm compatibility for ultrasonic spray coating process. These resins were dissolved in isopropyl alcohol, used for true solvent, and were diluted with ethanol, utilized for diluent. Also, solubilities, dispersion characteristics, and viscosities of these diluted polymer resin solutions were confirmed. Dispersion characteristic and viscosity of coating solution affects jetting of ultrasonic spray coating and these jetting characteristics influence morphologies of insulating layer. In conclusion, we have known that aqueous polymer solution should have outstanding dispersion characteristic and certain range of viscosity to fabricate thin polymer insulating layer uniformly with ultrasonic spray coating.

• 한국전기전자재료학회논문지
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• 제28권7호
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• pp.462-466
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• 2015

In this paper, we investigated the relations between dispersion of CNTs (carbon nanotubes) and electrical conductivity in the CNT/PVDF (polyvinylidene fluoride) composite film. By adding hydrophobic CNTs as filler into the PVDF matrix, we fabricated hydrophobic and electrically conducting polymer coating film. Dispersion of CNTs in the CNT/PVDF composite film plays a significant role in terms of electrical conductivity and wetting property. Spray coating method was used to form the CNT/PVDF composite films by injecting the dispersed CNTs in the PVDF solution with different weight ratios from 0.7 wt% to 7 wt%. We investigated the electrical properties and contact angles of the CNT/PVDF composite films with the CNT concentration. Finally we discussed the conducting mechanism and feasibility of the CNT/PVDF composite film for the conducting polymer films.

• 전기화학회지
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• 제6권2호
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• pp.113-118
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• 2003

폴리아닐린 분말과 고분자 계면활성제, cyclohexanone용매를 micro-milling장치내에서 분산시켜 (m입자 크기를 갖는 가공용이한 분산액을 제조하였다. 분산액을 백금 전극 위에 코팅하여 얻은 분산박막의 전기화학적 특성들은 순환전압전류법(CV)을 이용하여 조사하였다. CV의 결과에 의하면 폴리아닐린 분산박막이 순수한 폴리아닐린 박막과 유사한 전기화학적 특성을 갖는 것으로 나타났다. $3wt.\%$ NaCl용액에서 수행한 분극실험과 열린회로전위 측정 실험에서는 PANI분산액을 철표면에 코팅하면 부식전위가 증가하였다. 분산박막/철 전극의 열린회로전위값(OCP, Voc)이 분산액의 제조 조건에 따라 변화가 있음을 관찰하였다. 이러한 결과들은 본 연구에서 사용한 전도성 고분자 분산액이 철의 부식방지코팅물질로서 유용성을 갖고 있다는 것을 보여주고 있다.

• Korean Chemical Engineering Research
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• 제52권4호
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• pp.451-458
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• 2014

Isophrone diisocyanate (IPDI), polycarbonate diol (PCD)과 dimethylol propionic acid (DMPA)를 출발물질로 하여 수분산 폴리우레탄(waterborne polyurethane dispersion, WPUD)을 합성하였다. 이 WPUD에 아크릴 단량체인 methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA)와 butyl acrylate (BA)를 각각 첨가하여 다양한 종류의 수분산 아크릴 폴리우레탄(waterborne acrylic polyurethane dispersion, AUD)을 합성하였다. 이 AUD와 물에 분산된 다중벽 탄소나노튜브(multi-walled carbon nanotube, MWCNT)를 혼합하여 전도성 코팅 용액을 제조한 후 polycarbonate 시트 위에 도포하여 코팅 도막을 형성하고 물성을 살펴보았다. AUD로부터 제조된 코팅 도막의 연필경도, 내마모성 및 내약품성은 WPUD 보다 향상되었으나, 전기 전도도는 감소하였다. 또한 아크릴 단량체의 종류 변화 실험에서는 코팅 도막의 연필경도는 HEMA를 사용한 경우가 가장 우수하였으나, 내마모성, 내약품성 및 전기 전도도는 MMA를 사용한 경우가 가장 우수하였다.