• 약학회지
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• 제3권1호
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• pp.51-55
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• 1957

It has been suggested that the fluorine content of crude sea salt may have special value in the prevention of tooth decay, by A.E.Schaefer and J/H/.Shaw. Shaw calculated that if crude sea salt containing about 40 ppm of fluorine were used, the consumption of 26-44 grams of the salt per day for each prison would be sufficient for the prevention of tooth decay. He also suggested that this level of salt consumption is actually quite common among many population in the far and near east. In order to examine the fluorine contents of sea salt in Korea, several kinds of solar-evaporating salt and pan-evaporating salt were studied. The experimental results may be summarized as follows; 1. Fluorine contents of 9 kinds of solar-evaporating salt ranged from 3.8 to 15.0 ppm and the average was 7.52 $\pm$ 3.89 ppm. 2. Fluorine contents of 7 kinds of pan-evaporating salt ranged from 2.5 to 7.1 ppm. 3. The more the salt is refined, the less becomes the fluorine content. 4. Even the crudest sea salt can not contain about 40 ppm of fluorine. 5. Statistically, daily consumption of sea slat for each person in Korea is 28 grams.

• 한국응용과학기술학회지
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• 제34권3호
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• pp.650-656
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• 2017

The water-swollen hydrogels containing silicone or fluorine were prepared by copolymerization of 2-hydroxy ethyl methacylate (HEMA) with 3-(trimethoxysilyl)propyl methacrylate(SM) or 2,2,2-trifluoroethyl acrylate(FA). When the content of SM or FA increased in copolymers, there was tendency of water absorbance to decrease, whereas contact angles to increase. The hydrogels containing FA showed 2 ~ 4% higher water content and 4 ~ 5% lower contact angles compared to that of SM. Tensile strengths decreased as the content of SM increased. However, FA exhibited strength of $2.2Mpa/cm^2$ which is similar to $2.3Mpa/cm^2$ of B. FA, which implies comparatively low adherence, hence, showed better protein resistance properties than SM-based hydrogel. The photo-polymerization was also applied instead of thermal polymerization to enhance the energy efficiency. As a result, the reaction yield reached over 95% within 1 minute.

• 분석과학
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• 제33권6호
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• pp.262-273
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• 2020

식품 중 대표적인 오일 제형인 크릴오일 중에 불소 시험법 개발을 위해 식약처 "식품등 시험법 마련 표준절차에 관한 가이드라인"에 따라서 연소-이온크로마토그래피를 사용하여 크릴오일 중 불소 시험법을 개발하였다. 기존 크릴오일 중 불소 시험법은 전통적인 습식 전위차법이 사용되었으나, 신뢰성이 높지 않았고 국내에서는 이러한 오일 제형에 대해서는 불소 시험을 하는 식품검사기관이 없는 상황이었다. 이에 할로젠 시험법 관련 국가 및 국제표준으로 개발된 시험규격을 확인하였으며, 이 중에 오일 제형에 충분히 적용 가능한 연소-이온크로마토그래프 장비를 선택하여 크릴오일에 적합한 시험법을 개발하였다. 오일 제형의 특성상 시료준비 및 도입 시에 손실 및 각종 방해 (interference) 관련 우려를 사전 검토하여 다양한 실험을 통해서 최적의 시험법을 확립하였다. 개발된 오일 중 불소 시험법을 활용하여 유통되는 크릴오일 제품 11 개를 구입하여 불소함량 시험을 하였으며, 1개 시료를 제외한 대부분 제품들은 시험법에서 제시한 보고서 검출한계 미만으로 불검출을 확인하였다. 또한 불소가 검출되는 부분을 확인하기 위해 진행한 크릴새우 자체 시험한 결과, 크릴 부위에 따라서 농도가 다르긴 하지만, 몸통을 제외한 크릴 껍질부는 약 2,000 mg/kg ~ 3,000 mg/kg의 높은 불소함량이 검출됨을 확인하였다. 이후 확립된 시험법을 국제공인 시험기관 (ISO/IEC 17025) 2 곳에 시료를 의뢰하여 본 수행기관과 시험결과를 비교해 본 결과, 3개 실험실 간에 분산분석 통계처리에서 결과의 유의차가 없음을 확인하였고, 이에 본 내용을 토대로 크릴오일 중 불소함량 분석법 관련 시험법으로 적합함을 확인하였다.

• 한국분말재료학회지
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• 제30권6호
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• pp.516-520
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• 2023

Highly safe lithium-ion batteries (LIBs) are required for large-scale applications such as electrical vehicles and energy storage systems. A highly stable cathode is essential for the development of safe LIBs. LiFePO₄ is one of the most stable cathodes because of its stable structure and strong bonding between P and O. However, it has a lower energy density than lithium transition metal oxides. To investigate the high energy density of phosphate materials, vanadium phosphates were investigated. Vanadium enables multiple redox reactions as well as high redox potentials. LiVPO₄O has two redox reactions (V⁵⁺/V⁴⁺/V³⁺) but low electrochemical activity. In this study, LiVPO₄O is doped with fluorine to improve its electrochemical activity and increase its operational redox potential. With increasing fluorine content in LiVPO₄O_1-xF_x, the local vanadium structure changed as the vanadium oxidation state changed. In addition, the operating potential increased with increasing fluorine content. Thus, it was confirmed that fluorine doping leads to a strong inductive effect and high operating voltage, which helps improve the energy density of the cathode materials.

• Bulletin of the Korean Chemical Society
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• 제13권2호
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• pp.131-135
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• 1992

High-Tc superconducting materials, $HoBa_2Cu_3O_{7-x}F_y$ with $0.0{\leq}y{\leq}0.5$, were synthesized by ceramic method and studied by X-ray diffraction, thermogravimetric analysis, differential thermal analysis, scanning electron microscopy and resistivity measurement. From the X-ray diffraction data, it was found that the samples had only single phase of which lattice volumes were decreased in proportional to the amount of fluorine, which indicated that the relatively small fluorine atoms are effectively substituted for the oxygen sites. Also, an anomalous phenomenon appeared that the peak intensities of (001) planes were greatly increased as fluorine contents increased. SEM photographs revealed that the grain sizes were enlarged progressively with fluorine contents. This fact could be explained along with DTA & TGA data that the incorporation of fluorine gave rise to lowering the melting point. Tc decreased as the incorporation of fluorine content increased. This implies that the superconducting electrons are perturbed due to the substitution of electronegative fluorine atom.

• 폴리머
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• 제29권2호
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• pp.172-176
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• 2005

불소의 함량이 $62\%$인 불소화된 폴리올($Fluorolink^{(R)}$:평균분자량 1000)을 이용하여 환경친화적인 불소함유 수분산 폴리우레탄을 합성하였다. 사용된 diisocyanate는 isophorone diisocyanate(IPDI)였으며, 폴리우레탄 내 불소의 함량 조절을 위해 폴리올은 poly(tetramethylene glycol)(PTMGG2000)과 $Fluorolink^{(R)}$을 정해진 비율로 조절하였고 친수성 음이온기의 도입을 위해 dimethanol propionic acid(DMPA)를 사용하였다. 이온성 작용기는 수분산 전에 triethyl mine(TEA)으로 중화하여 생성하였으며, 최종적으로 ethylene diamine(EDA)을 이용하여 사슬연장하였다. 기계적 물성을 측정한 결과 불소의 함량이 증가함에 따라 탄성률은 증가하였으나, 파괴 변형률은 감소하는 것을 알 수 있었다. 접촉각으로부터 얻은 표면에너지 값은 불소함량에 따라 감소하였으나 $Fluorolink^{(R)}$가 $20\%$ 이상에서는 큰 변화가 없어 소량의 $Fluorolink^{(R)}$ 만으로도 불소함유의 충분한 효과를 얻을 것으로 예상된다. 또한 열적 성질을 알아본 결과, $Fluorolink^{(R)}$의 함량이 증가할수록 $T_g$와 열분해온도가 낮아졌는데 이것은 soft segment를 구성하는 $Fluorolink^{(R)}$의 $T_g$와 분해온도가 PTMG 2000보다 낮기 때문에 나타나는 현상으로 여겨진다.

• 한국콘텐츠학회논문지
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• 제15권11호
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• pp.329-337
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• 2015

불소는 적정 농도에서는 치아우식 예방 효과를 증진시키는 원소이지만 불소에 대한 정확한 정보를 인식하지 못하는 경우에는 치아우식 예방에 좋지 못한 큰 영향을 미친다. 이에 본 연구는 대학생을 대상으로 불소에 대한 인식도를 평가하고 인식도에 따른 구강건강상태를 분석함으로서 우식예방효과를 증진시키고 불소에 대한 올바른 지식을 전달하고자 한다. 본 연구는 2014년 5월1일부터 6월30일까지 대구 경북 지역에 거주하는 대학생 중 남성 82명 여성 102명을 대상으로 설문조사와 구강건강상태를 평가하기 위해 구강검진을 실시하였다. 연구결과 불소 인식도에 따른 DT rate 치과 외에 불소사용 인식도는 '없다'가 19.46%로 '있다' 11.10%보다 높았다(p<.05). 불소함유제품 사용표시 확인은 '아니오'가 18.32%로 가장 높아 주의표시를 읽지 않을수록 높게 조사되었다(p<.05). 불소 인식도에 따른 FT rate 치과에서의 불소사용의 인식도는 '있다'가 71.98%로 '없다' 49.04%보다 높았다(p<.05). 불소인식도가 구강건강상태에 미치는 영향을 파악함으로서 향후 불소예방사업을 수행함에 있어 기초자료를 마련하는데 의의가 있고 이상의 결과를 바탕으로 불소에 대한 인식을 높이기 위한 적극적인 교육과 홍보가 이루어져야 한다고 생각된다.

• 한국세라믹학회지
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• 제27권7호
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• pp.925-933
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• 1990

The possible use of bioglass,, which is one of the surface active biomaterials, as implants materials has drawn great attention due to their ability to bond to human living tissue. In the present work, the investigation was carried out to find the bonding phenomena between alumina substrate and bioglass(45S5) or fluorine-containing bioglass(45S5$.$4F), and the properties of coated bioglass. The stable bonding between alumina and bioglass was formed when heat-treated at 1150$^{\circ}C$ for 120 minutes or at 1250$^{\circ}C$ for 30 minutes for the 45S5, and at 1150$^{\circ}C$ for 30 minutes for the 45S5$.$4F. When bioglass coated alumina was heat-treated, great amount of Al was diffused into bioglass from alumina substrate. More Al was diffused into fluorine-containing bioglass than into bioglass without fluorine. At early stage of heat-tretment, the diffused alumina content was increased with the square root of time and it was also increased with the thickness of coating layer and heat-treatment temperatures. The alumina content became constant after its saturation for longer heat-treatment time. Coated bioglasses were crystallized to Na2O$.$CaO$.$3SiO2 when heat-treated at lower temperature, and to CaO$.$SiO2 at higher temperature.

• Carbon letters
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• 제28권
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• pp.66-71
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• 2018

To improve the flame retardant performance of cellulose fibers, fluorine functional groups were introduced under various controlled fluorination conditions. The properties of the fluorinated cellulose fibers were analyzed by X-ray photoelectron spectroscopy and a thermogravimetric analysis. The fluorine functional group content in the fluorinated cellulose fibers increased with an increase in the fluorination temperature. However, the fluorination reaction increased the char yield and decreased the rate of degradation of the cellulose fibers by introducing donors, enabling the formation of a thick and compact char layer. Therefore, the flame retardant properties of cellulose fibers were improved following the fluorination treatment.

• Composites Research
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• 제30권1호
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• pp.41-45
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• 2017

Magnetite nanoparticles were synthesized by adding an ammonium hydroxide to a mixed solution of iron (II) and (III) chlorides. A silicon surfactant of ${\alpha},{\omega}$-(3-aminopropyl)polydimethylsiloxane was adsorbed on the particles as dispersant and a polydimethylsiloxane polymer was used to prepare ferrofluids of silicone oil base. Fluorinated surfactants of anionic ammoniated perfluoroalkyl sulfonamide and nonionic fluoroaliphatic polymeric esters were applied to the particles and a perfluoropolyether was used to prepare ferrofluids of fluorine oil base. The experimental conditions were used for preparing the ferrofluids with concentrations of 200, 300 and 400 mg/mL, and density, magnetization and viscosity of the products were characterized. The density values increased in proportion to the concentration, indicating 1.11-1.27 g/mL for silicone-oil-based fluids and 1.95-2.10 g/mL for fluorine-oil-based fluids in the range of 200-400 mg/mL. The saturation magnetization of the silicone-oil-based and fluorine-oil-based fluids indicated 14.7, 24.4, and 30.7 mT and 15.8, 23.3, and 33.7 mT for 200, 300, and 400 mg/mL, respectively, depending on the content of magnetic particles in the fluid. The viscosity of the silicone-oil-based ferrofluids was highly stable compared to that of the fluorine-oil-based with increasing temperatures. The ferrofluids are usually applied to seals and speakers with the silicone base and to seals with the fluorine base.