• 한국응용과학기술학회지
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• 제28권1호
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• pp.35-47
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• 2011

For the synthesis of water soluble acrylic modified epoxyester resin, fatty acid/epoxy ratio of 50/50 was used, and introduced maleic anhydride. Ratio of styrene/acrylic acid of acrylic monomers was fixed 85/15 and ratio of epoxyester/acrylic monomer was controlled 80/20, 75/25, 70/30, 65/35, and degree of neutralization were changed 65%, 80%, to 100%. As a result, 40% solids acrylic modified epoxyester resins were synthesized. Resins were evaluated water soluble stability, drying time, water resistant, storage stability and physical properties. And the white paints were prepared, and were evaluated viscosity, drying time, water resistance, adhesion, sagging, spray workability, gloss, salt spray resistance, skinning, whiteness and flash rust. As a result, the degree of neutralization of 100% and the ratio of epoxyester/acrylic monomer of 75/25 showed the best properties.

• 공업화학
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• 제7권3호
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• pp.536-542
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• 1996

본 연구에서는 유화중합을 통해 water jet loom용 경사 호제인 비용제형 수용성 아크릴 호제(GSW-7000)를 합성하였다. 이 호제는 아크릴계 호제의 암모늄염 형태로 제조되어 weaving force에 대한 저항력과 water jet loom 사용에 있어 물에 대한 저항력이 우수하였다. 제조한 GSW-7000은 sizing에 적당한 점도를 가지고 있고, 신도와 접착력, 용해성, 침투성 및 호부착성이 우수하였다. 또한 본 호제로 처리된 호부사는 접착강도가 높아 기존 용제형 아크릴 호제에 비하여 sizing시 호제 소모량을 70~80% 수준으로 저하시켜도 우수한 집속성 및 포합력을 나타내었으며, 호피막이 유연하며 평활성 및 내마모성이 우수하여 호부시 유제 및 대전 방지제를 사용하지 않아도 sizing 및 제직이 가능하였다.

• 한국포장학회지
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• 제5권1호
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• pp.37-46
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• 1999

Water vapor permeability of films is commonly calculated from the water vapor transmission rate of the film measured using a permeability cup method which is essentially a gravimetric method. This method was originally developed for petroleum based plastic films with low water vapor permeability. In the case of hydrophilic bio-polymer films, the resistance caused by a stagnant air layer, which is developed between the underside of the film mounted on the cup and the surface of the desiccant saturated salt solution or distilled water, can be significant and, if neglected, ran lead to underestimation of water vapor transmission rates. Therefore, it is necessary to correct water vapor transmission rate data to accurately estimate the water vapor permeability of bio-polymer films.

• Macromolecular Research
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• 제17권4호
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• pp.227-231
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• 2009

New polyelectrolytes derived from poly(amide-sulfone)s and 1,5-dibromopentane were simultaneously fabricated on the electrode by the crosslinking reaction. The substrate was pretreated with a bromoalkyl-containing, silane-coupling agent to anchor the humidity-sensitive membrane to the substrate through the covalent bond. When the resistance dependence on the relative humidity of the crosslinked poly(amide-sulfone)s was measured, the resistance varied by three orders of magnitude between 20%RH and 90%RH, which was the required RH range for a humidity sensor operating at ambient humidity. Their water durability, long-term stabilities under various environments, hysteresis and response and recovery times were measured and evaluated as a humidity-sensing membrane.

• Membrane and Water Treatment
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• 제3권3호
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• pp.169-179
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• 2012

One of the major limitations in the use of commercial aromatic polyamide thin film composite (TFC) reverse osmosis (RO) membranes is to maintain high performance over a long period of operation, due to the sensitivity of polyamide (PA) skin layer to oxidizing agents, such as chlorine, even at very low concentrations in feed water. This article reports surface modification of a commercial TFC RO membrane (BW30-Dow Filmtec) by covering it with a thin film of poly(vinyl alcohol) (PVA) crosslinked with glutaraldehyde (GA) to improve its resistance to chlorine. Crosslinking reaction was carried out at 25 and $40^{\circ}C$ by using PVA 1.0 wt.% solutions at different GA/PVA mass ratio, namely 0.0022, 0.0043 and 0.013. Water swelling measurements indicated a maximum crosslinking density for PVA films prepared at $40^{\circ}C$ and GA/PVA 0.0043. ATR-FTIR and TGA analysis confirmed the reaction between GA and PVA. SEM images of the original and modified membranes were used to evaluate the surface coating. Chlorine resistance of original and modified membranes was evaluated by exposing it to an oxidant solution (NaClO 300 mg/L, NaCl 2,000 mg/L, pH 9.5) and measuring water permeability and salt rejection during more than 100 h period. The surface modification effectively was demonstrated by increasing the chlorine resistance of PA commercial membrane from 1,000 ppm.h to more than 15.000 ppm.h.

• 한국식품영양과학회지
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• 제36권1호
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• pp.72-80
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• 2007

다양한 소금의 첨가가 제빵 특성에 미치는 영향을 알아보기 위하여 기계염, 국산 천일염, 중국산 천일염, 멕시코산 천일염, 구운 소금, 죽염을 첨가하여 반죽과 식빵을 제조하고 각각의 특성을 조사하였다. Farinograph로 측정한 반죽의 흡수율은 소금의 첨가로 감소하였으며, 기계염의 경우가 흡수율 감소가 작아 가장 높은 흡수율을 나타내었다. 반죽의 면적과 저항면에서는 국산, 중국산, 멕시코산 천일염과 죽염 등이 크게 나타나 우수한 제빵적성을 보였다. Amylograph로 측정한 paste의 최고점도는 기계 염, 천일염, 세척탈수염 첨가군은 큰 차이를 나타내지 않았으나 구운 소금과 죽염 첨가군은 다소 높았다. 식빵의 비용적은 국산 천일염 첨가군이 4.11 mL/g으로 가장 작았으며 멕시코산 천일염 첨가군은 4.85 mL/g으로 부피 증가가 가장 컸다. 빵의 무게는 국산 천일염 첨가군에서 412.4g으로 가장 높아 굽기 손실율 에서 국산 천일염 첨가군(10.34%)이 다른 첨가군(10.91$\sim$11.65%)에 비해 낮았다. 식빵의 색도에서는 국산 천일염 첨가군의 경우 빵 껍질의 명도가 크고 적색도가 낮았고, 빵내부의 황색도는 높았으며, 다른 첨가군은 큰 차이를 보이지 않았다. 저장 초기의 식빵의 경도는 세척 탈수염 첨가군이 가장 낮았고 중국산 천일염 첨가군이 가장 높았으며 저장기간 1, 3, 5일 경과함에 따라 멕시코산 천일염과 중국산 천일염 첨가군은 경도가 크게 증가했다. 식빵의 관능검사 결과 소금의 종류에 따른 식빵의 내 외부적 제품 특성에서 국산 천일염 첨가군과 멕시코산 천일염 첨가군이 유의적 차이를 보였으며 향, 맛, 전체적인 기호도에서는 유의적 차이를 보이지 않았다.

• 열처리공학회지
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• 제15권5호
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• pp.213-218
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• 2002

In order to develop the economic and environmental water-soluble black coloring agent, some adequate chemical mixtures were mixed and this solution was applied to coat quenched and tempered 51B20 steel bolt. Some basic properties of the solution and characteristics of the coated film in addition to the corrosion resistance were investigated. The developed 100 kg of water-soluble black coloring agent solution was a chemical mixture consisted of 10 kg of aqueous coloring agent, 40 kg of surface active agent, 0.3 kg of anti-foam agent and $50{\ell}$ of water. The coated film of the bolt was composed of hard layer of about $2{\mu}m$ and the disbondable soft layer of about $4{\mu}m$ above the hard layer. Many surface active agents peaks and a few hydrophilic peaks were observed in the coated film. Surface roughness value of the coated bolt was lower than that of the non-coated bolt. Corrosion resistance of the coated bolt considerably improved and also relatively showed a good polarization resistance at test condition of $40^{\circ}C$ colorizing temperature and 5% the solution concentration in 3% NaCl anodic polarization test. Initial appearance time of the surface rust was greatly retarded owing to the coated film in salt spray test.

• 대한안전경영과학회지
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• 제2권3호
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• pp.197-210
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• 2000

In this paper, sensor ring for antilock brake system was studied using the 400 series ferrite stainless steel powder. Because of more excellent corrosion resistance and mechanical characteristics than iron, sensor ring has been manufactured by P/M(Powder Metallurgy) method 400 series ferrite stainless steel. the results are following. 1, Compared with sensor ring made by iron, 400 series ferrite stainless steel has shown a good corrosion resistance without an addition surface treatment. thus the decreasing production process has been obtained. 2. The products before sintering are much more corrodible in the condition of spray test of salt water and ammonia than humidity and nitrogen condition.

• Corrosion Science and Technology
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• 제15권1호
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• pp.28-37
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• 2016

Due to the increased construction of offshore concrete structures and the use of de-icing salts for the purpose of snow removal, the needs for the development of anti-corrosive concrete are increasing. To solve these problems, an evaluation of the mechanical and durability properties for concrete were conducted by mixing modified-sulfur as 0 %, 5 %, 10 %, 15 % cement weight ratio. Both strengths and the properties affecting durability such as water absorption coefficient, chloride ion permeability, accelerated carbonation resistance, rapid freezing and thawing, and chemical resistance were evaluated. All evaluations performed were according to the test specifications associated KS. The results indicate that mixing of modified-sulfur lowed chloride ion permeability and improved chemical resistance.

• Membrane and Water Treatment
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• 제1권1호
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• pp.13-37
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• 2010

The performance of an electrodialyzer for concentrating seawater is predicted by means of a computer simulation, which includes the following five steps; Step 1 mass transport; Step 2 current density distribution; Step 3 cell voltage; Step 4 NaCl concentration in a concentrated solution and energy consumption; Step 5 limiting current density. The program is developed on the basis of the following assumption; (1) Solution leakage and electric current leakage in an electrodialyzer are negligible. (2) Direct current electric resistance of a membrane includes the electric resistance of a boundary layer formed on the desalting surface of the membrane due to concentration polarization. (3) Frequency distribution of solution velocity ratio in desalting cells is equated by the normal distribution. (4) Current density i at x distant from the inlets of desalting cells is approximated by the quadratic equation. (5) Voltage difference between the electrodes at the entrance of desalting cells is equal to the value at the exits. (6) Limiting current density of an electrodialyzer is defined as average current density applied to an electrodialyzer when current density reaches the limit of an ion exchange membrane at the outlet of a desalting cell in which linear velocity and electrolyte concentration are the least. (7) Concentrated solutions are extracted from concentrating cells to the outside of the process. The validity of the computer simulation model is demonstrated by comparing the computed results with the performance of electrodialyzers operating in salt-manufacturing plants. The model makes it possible to discuss optimum specifications and operating conditions of a practical-scale electrodialyzer.