• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.201-201
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• 1999

소수성의 특성을 가지는^g , pp (polypropylene)의 표면을 이온 보조 반응법(IAR)으로 처리하여 친수성으로 개질하였다. 이온빔 보조 반응법은 고에너지 이온빔을 이용한 기존의 표면처리 방식과는 달리 1keV 영역의 에너지를 가진 이온빔을 조사하면서 시료 주위에 반응성 가스를 불어넣어 줌으로써 표면의 성질을 변화시키는 방법이다. 여기서 조사된 수소이온의 에너지는 0.6에서 1.0keV까지 변화시키고 시료의 주변에 불어주는 산소의 양은 0에서 8ml/min으로 변화시켰으며 이온 조사량은 5x1014에서 1x1017ions/$\textrm{cm}^2$까지 변화시켰다. 그 결과 처리하지 않은 시료의 접촉각은 93$^{\circ}$이었으며 이온조사량이 1x1017ions/$\textrm{cm}^2$이고 가속에너지가 1.0keV인 조건에서 수소 이온빔만으로 처리한 시편의 경우 접촉각은 60$^{\circ}$정도 였으나 수소이온보조 반응법으로 처리한 시편의 경우는 $10^{\circ}$이하까지 접촉각이 감소하였음을 알 수 있었다. 이는 표면처리에 따른 표면의 친수성 작용기의 형성을 예상할 수 있으며 그 존잴르 확인하기 위하여 대기중과 물속에서 각각 보관한 시료의 접촉각과 표면에너지를 계산하여보았다. 그 결과 대기중에서 방치한 시편의 경우40$^{\circ}$ 정도로 감소하였으나 증류수에 보관한 시료의 경우는 15$^{\circ}$정도의 변화를 보였다. 물과 Formamide의 접촉각의 측정으로 표면에너지를 계산한 결과 산소분위기에서 수소이온빔으로 처리된 시료는 23dyne/cm에서 64dyne/cm이상까지 변화함을 관찰하였다. 위의 결과들이 표면거칠기에 미치는 영향을 고찰하기 위해 처리되지 않은^g , pp 의 근(root mean square)값은 8.30nm이었고 1kevdpsj지에서 불어준 산소4ml/min이고 이온 조사량이 1x1017ions/$\textrm{cm}^2$인 경우 접촉각은 $10^{\circ}$를 나타냈으며 rms값은 20.8nm를 나타내었다. XPS (X-ray photoelectron spectroscopy) 분석을 통하여 1x1017ions/$\textrm{cm}^2$에서 산소기체를 4ml/min 불어넣어준 후 C-O, C=O, (C=O)-O등의 친수성 작용기가 형성되었음을 확인하였다.^g , pp 의 접착력을 알아보기 위해 유성 페인트를 전도성 고분자위에 후막 처리하였다. 스카치 테이프를 테스트를 통하여 이온 보조 반응법으로 처리된^g , pp 표면이 처리하지 않은 시편에 비하여 접착력 향상되었음을 확인하였다.

• Polymer(Korea)
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• v.28 no.2
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• pp.135-142
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• 2004

Poly(vinyl acetate) (PVAc) prepared by emulsion polymerization has broad applications for additives such as paint binder, adhesive for wood and paper due to its low glass transition temperature which help to plasticize substrate resins. Since emulsion polymerization has a disadvantage that surfactant and ionic initiator degrade properties of the product polymer, poly(vinyl acetate-co-butyl acrylate) (VVc-BA) was synthesized using potassium persulfate as catalyst and poly(vinyl alcohol) (PVA) as protective colloid to prevent the degradation. The copolymer latex product was internally plasticized and has enhanced colloid stability, adhesion, tensile strength and elongation. During VAc-BA emulsion polymerization, no coagulation and complete conversion occur with the reactant mixture of 0.7wt% potassium persulfate, 15wt% poly(vinyl alcohol) (PVA-217), and the balanced monomer that the weight ratio of vinyl acetate to butyl acrylate is 19. As the concentrations of PVA increase, the copolymerization becomes faster and polymer particles are more stable, resulting in enhanced mechanical stability of the VAc-BA copolymer. However, the size of the polymer particles decreases with increasing PVA contents. Properties of the VAc-BA copolymer, such as minimum film formation temperature, glass transition temperature, surface morphology, molecular weight and molecular weight distribution, tensile strength and elongation, were characterized using differential scanning calorimeter, transmission electron microscope and other instruments.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.182-182
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• 2003

1.연구목적 : Cr $O_3$은 금속 도금용, 페인트 둥에 많이 사용되며 독성이 강하여 그동안 근로자 건강장해 및 직업병 사례가 많이 발생하였다. 그러나 산화크롬의 흡입에 의한 연구자료는 매우 부족하다. 이에 흡입챔버를 이용 Rats에 흡입노출을 통하여 유해성을 평가하고 각 장기에 흡수되는 크롬의 농도평가와 회복기간에 따라 각 장기별로 흡수된 크롬의 소실속도 둥을 연구하였으며 더불어 회복기간과 제거율의 상관관계 및 체내 반감기 등을 연구하였다. 2. 연구방법 : Cr $O_3$를 폐내 침착율 및 흡수율이 높은 0.5～5$\mu\textrm{m}$ 크기의 aerosol형태로 SD Rats 수컷에 전신폭로 하였다. 노출농도는 0.00, 0.20, 0.50, 1.25mg/㎥(Cr)으로 하여 1일 6시간, 주 5일, 13주간 반복 노출하였고 회복군은 시험물질 종료일을 기준으로 2주, 8주 경과 후 조직장기와 전혈, 혈장 및 적혈구내, 뇨 중 각각의 크롬농도를 분석하였으며 혈액 및 혈액 생화학적 검사도 병행하였다 3. 연구결과 : 혈액검사에서 0.20, 0.50 mg/㎥ 농도군 실험동물의 RBC와 HGB, HCT 둥은 감소의 경향을 보였으나 농도 의존적이지는 않았다. 신장의 절대중량은 대조군에 비해 유의하게 (p<0.05) 감소하고 폐장의 경우는 대조군에 비해 유의한(p<0.05) 절대중량 증가를 보였다 시험물질 노출 후 혈액 중 전혈, 혈장, 적혈구의 회복기간(x)별 크롬농도(y)의 소실속도 상관계수 (노출농도 0.50mg/㎥군의 경우)는 y = 66.51 $e^{0.057}$x/, y = 67.2 $e^{0.101}$x/, y = 70.01 $e^{0.030}$x/, 반감기는 12.0, 6.86, 23.0 일이고 폐장, 간장, 신장의 회복기간(x)별 크롬농도(y)의 소실속도 상관계수 (노출농도 0.50 mg/㎥군의 경우)는 y = 1808 $e^{0.004}$93x/, y = 12.02 $e^{0.029}$7x/, y = 67.61 $e^{0.029}$2x/ 반감기는 140.6, 23.3, 23.7 일로 평가되었다. 4. 고찰 : 실험동물의 전혈, 혈청, 뇨에서의 크롬농도와 시험물질 노출농도는 밀접한 상관을 가졌으나 농도에 정비례하지는 않았다. 뇨 중 흡수된 크롬의 경우 회복기간 초기 (12시간 내)에 대부분 배설이 일어나는 것으로 나타났다. 폐장이 간장, 신장 등 다른 장기에 비해 높은 축적량을 보였으며 축적된 크롬농도가 높을수록 크롬의 소실속도는 현저히 저하하는 경향을 보였다. 노출농도가 높을수록 각 장기조직 내 크롬의 소실속도 (clearance)는 크게 감소경향이 있었으며 이는 체내 과부하시 자정작용이 감소하는 것으로 판단되었다. 본 연구 결과 SD rat를 이용 반복흡입노출의 경우 생체의 무유해영향농도 (NOAEL)는 0.2mg/㎥이하이며 발암물질을 감안하여 안전계수를 100으로 할 경우 사람에 대한 NOAEL은 0.002mg/㎥이하로 판단되었다. 특히 호흡기와 폐장에 강한 유해성을 나타내는 것으로 확인되었다. 것으로 확인되었다.

• Journal of the Korean Ceramic Society
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• v.39 no.12
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• pp.1143-1148
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• 2002

Precipitated calcium carbonate is one of the most versatile mineral fillers and is consumed in an wide range of products including paper, paint, plastics, rubber, textiles, sealants, adhesives and printing ink and can be produced by several methods. Calcium carbonate has three isomorphism; vaterite, aragonite and calcite, with numerous variations of morphology in the natural mineral or organism. Formation process of vaterite in the reaction of system $Ca(OH)_2-CH_3OH-H_2O-CO_2$ were investigated by measuring the electrical conductivity, $Ca^{2+}$ ion concentration, pH in the slurries and by means of X-ray diffraction and electron microscopic observation. It was clearly established that the reaction temperature is important variable in the carbonation process; in general over 50${\circ}C$, the vaterite was precipitated with the calcite and aragonite. SEM and XRD observations revealed that the vaterite formation could be prepared the temperature range of 40 to 50${\circ}C$ and mean size of particles in this range is controlled from 0.5 to 0.8 ${\mu}m$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.6
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• pp.731-737
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• 1992

The specific attributes of aroma quality of canned tuna meat were investigated before and during refrigerated storage. Fresh, cooked tuna, beefy and meaty flavor notes of canned tuna meat were changed to card-boardy(1 week storage), oxidized fat-like(2 weeks storage), fatty acid-like and heavy oxidized fat-like(3 weeks storage), and then moldy and painty(4 weeks storage) flavor notes during storage in refrigerator at $4^{\circ}C.$ More than 126 peaks of volatile compounds collected from canned tuna meat were separated on Carbowax 20M capillary column of gas chromatographic analysis. Of the peaks, 54 compounds were identified by mass spectral data, matching $I_E$ values, and sniffing the effluent of each peak from GC detector. The contents of many low molecular weight compounds eluted with early retention times were decreased, whereas some other new compounds eluted with longer retention time were formed during storage. The compounds increased up to 3 weeks of storage and then decreased at extended storage time(4 weeks) were 1-penten-3-ol, 3-penten-2-ol, heptanal, limonene, 1-pentanol, octanal, 1-hexanol, nonanal, 2-octanone, 2-nonanone, 1-heptanol, benzaldehytde and some methyl substituted benzenes. p-Thiocresol, 2-chlorophenol, and 2-heptylthiophene were formed after 4 weeks of storage, but not detected in fresh canned tuna. Therefore, these compounds could be used as indicators for the quality changes during refrigerated storage.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.4
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• pp.153-159
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• 2015

Inorganic pigments have been received a great attention for various applications including paint, glazed ceramic ink, art tile, and building exterior due to their excellent thermal and chemical stability. Traditionally, the compositions of $PbCrO_4$, CdS and CdSe have been widely used as a yellow inorganic pigment. However, the use of these compositions has been restricted in recent years, because they contain harmful elements such as Cd, Cr, Pb and Se. In this study, new environment-friendly ceria-based pigment was synthesized using solid state reaction. Crystal structure and morphology of the obtained $Ce_{1-x}Zr_xBi_yO_{2-y/2}$ yellow pigment were analyzed using XRD and SEM, respectively. Substitutional effect of Zr and Bi on the pigment color was analyzed using UV-vis. spectrophotometer and CIE $L^*a^*b^*$ analysis. The crystal structure of the obtained pigments was dependent on the calcination temperature. The color characteristics and absorption band of the pigments were dependent on the calcination temperature and Zr, Bi contents. As a result, all the obtained yellow pigments showed the effective absorption ranged from ultraviolet to visible light, and $Ce_{0.44}Zr_{0.36}Bi_{0.20}O_{0.19}$ (x = 0.36, y = 0.20) pigment showed the most brilliant yellow color.

• Journal of the Korean Applied Science and Technology
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• v.36 no.2
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• pp.645-655
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• 2019

In this study, colloidal microgel with viscoelasticity were prepared by using dispersion containing physical crosslinking agents and microgels with various strengths depending on the degree of cross-links.As the chemical crosslinking agent PEGDA400 content increased, hydrogels have various physical properties the swelling ratio decreased from $2.0{\times}10^4%$ to $6.0{\times}10^3%$ and increased viscosity by about 60%. The colloidal microgel was prepared with micro hydrogel grinded to $100{\mu}m$ size and the rheological behavior was confirmed with physical cross linking agent. A colloidal microgel having various viscosities was prepared by controlling starch and alginate based on micro-hydrogel containing 0.75% (w/v) of PEGDA400. In conclusion, these results would be highly useful for applying as a product that can give various physical properties to the colloidal suspensions, cosmetics, paint, and food industry.

• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.581-587
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• 2022

The leather industry generates a large amount of hazardous leather waste of various types every year. Among them, shaving scrap is difficult to recycle because it contains chromium ions. Many studies in recent years have shown that shaving scraps can be processed into various types of valuable products, such as adsorbent, filler, and poultry feed. In this study, collagen peptides were extracted from shaving scraps and structurally modified to be developed as new materials with improved physicochemical properties. First, the chromium ions contained in the shaving scraps were removed using a sodium hydroxide solution, and purified through concentration and low-temperature crystallization. The purified collagen peptide was used to prepare the powder using a spray dryer. The extracted collagen peptides were structurally modified by introducing double bonds by reacting with methacrylic anhydride (MAA), and the product was confirmed by ¹H NMR spectroscopy. Next, a copolymer was prepared by redox polymerization of the modified collagen peptide (MCP) and 2-ethylhexyl acrylate (2-EHA). The structure of the copolymer was qualitatively confirmed by FT-IR. In conclusion, this study confirmed that collagen peptides can be extracted from shaving scrap and converted into new eco-friendly materials through certain treatments.

• Economic and Environmental Geology
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• v.56 no.3
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• pp.229-238
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• 2023

Bentonite is a type of rock that has been used as a traditional mineral medicine. It has a variety of pharmacological activities, and is used in traditional Korean medicine to treat jaundice, diarrhea, and hemostasis. In modern medicine, it is used as a raw material and additive for medicines such as antacids, gastrointestinal protective agents, and laxatives. Bentonite produced in Korea was produced through diagenesis or hydrothermal alteration of tertiary volcanic debris distributed in the Pohang and Gyeongju areas. It is mainly used for industrial purposes such as papermaking, paint, civil engineering, casting, and animal feed. Recently, technology is being developed to use it in cosmetics and pharmaceuticals. In this study, the geochemical characteristics of bentonite were identified by analyzing the main components and trace elements of 40 and 21 types of bentonite produced in the Gampo Gyeongju and Yeonil Pohang area. Also it were classifed by formation envrionment of bentonite deposits in the Gampo and Yeonil. As a result of the study, bentonite from the reserch area may be cased by argillic alteraton that alkali elements are removed form basaltic rocks by hydrothermal fluids and AI-CCPI alteration indices wrere also indentified argillic alteraton. It was found that there is a correlation between the behavior characteristics of heavy metal elements (P b, Cr, As) and the hydrothermal alteration of bentonite in the reserch area.

• Conservation Science in Museum
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• v.29
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• pp.133-152
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• 2023

This study references preceding studies to examine the history of paint application techniques using various paints in the past, with the aim to contribute to the long-term preservation of large military cultural heritage assets situated outdoors. To this end, the study compared the findings of preceding research with the findings of an analysis conducted on a H-13 helicopter housed at the War Memorial of Korea. Upon collecting and analyzing samples from three grounded WWII aircraft from above-ground by preceding studies, it was confirmed from each sample that the various chemical properties of chrome ensured the effectiveness of the protective coating. The compound was first tested as a corrosion-inhibiting pigment in the early 1940s and proved its excellent moisture-resistant properties over the course of 80 years, despite the deterioration of the paint layer and long-term exposure to the natural environment. For this reason, it has been widely used as a corrosion inhibitor for aluminum alloys in the aviation industry. In other word, the most widely-used material for preventing corrosion was an organic primer containing chromate. In this study, based on the paint analysis of a H-13 helicopter operated in the Korean War, it was shown that the second layer, consisting of the primer, contains chromium oxide (Cr₂O₃). In addition, it was estimated that red lead tetraoxide (Pb₃O₄) was used for the vehicle. Analysis results and data from previous studies can help to confirm the continued effectiveness of corrosion prevention function provided by chromate. Meanwhile, the result of infrared spectroscopy analysis confirmed the use of alkyd resin. In the future, comparisons with a more diverse range of artifacts will allow the identification of changes in the manufacturing technology of paints used to protect alloys from corrosion.