• 한국재료학회지
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• 제33권4호
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• pp.124-129
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• 2023

This study assessed the influences of fluorine introduced into DLC films on the structural and mechanical properties of the sample. In addition, the effects of the fluorine incorporation on the compressive stress in DLC films were investigated. For this purpose, fluorinated diamond-like carbon (F-DLC) films were deposited on cobalt-chromium-molybdenum substrates using radio-frequency plasma-enhanced chemical vapor. The coatings were examined by Raman scattering (RS), Attenuated total reflectance Fourier transform infrared spectroscopic analysis (ATR-FTIR), and a combination of elastic recoil detection analysis and Rutherford backscattering (ERDA-RBS). Nano-indentation tests were performed to measure hardness. Also, the residual stress of the films was calculated by the Stony equation. The ATR-FTIR analysis revealed that F was present in the amorphous matrix mainly as C-F and C-F₂ groups. Based on Raman spectroscopy results, it was determined that F made the DLC films more graphitic. Additionally, it was shown that adding F into the DLC coating resulted in weaker mechanical properties and the F-DLC coating exhibited lower stress than DLC films. These effects were attributed to the replacement of strong C = C by feebler C-F bonds in the F-DLC films. F-doping decreased the hardness of the DLC from 11.5 to 8.8 GPa. In addition, with F addition, the compressive stress of the DLC sample decreased from 1 to 0.7 GPa.

• 생명과학회지
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• 제32권5호
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• pp.362-367
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• 2022

대마씨의 외종피를 탈각하여 Tetrahydrocanabinol이 제거된 헴프씨드는 건강식품으로 각광받고 있으며, 헴프씨드 오일은 α-linolenic acid 및 γ-linolenic acid 등의 다가 불포화 지방산 및 지용성 비타민 등이 풍부하여, 인지 기능 및 운동기능 개선, 콜레스테롤 감소, 혈관 염증 완화, 혈전 생성 억제, 신경세포 손상 방지 등의 효능이 알려지면서 수요가 급증하고 있다. 현재 헴프씨드 오일은 여타의 식물성 유지(콩기름, 옥수수유, 올리브유, 카놀라유, 아미씨유)보다 45~140배 이상 고가로 판매되고 있다. 본 연구에서는 FTIR, FTIR-Raman, ATR-FTIR-MIR spectroscopy와 같은 고가의 장비와 전문인력에 의한 분석 없이도 헴프씨드 오일의 진위여부를 판별할 수 있는 간편한 UV-Vis spectrophotometry법을 개발하고자 하였으며, 다양한 오일의 245, 305, 및 415 nm 흡광도를 측정하고, 245/415 nm 및 305/415 nm에서의 흡광도의 비를 계산하여 12.9 및 9.6이 나타나는 경우 헴프씨드 오일임을 확인하였다. 콩기름, 옥수수유, 카놀라유 및 아미씨유의 경우에는 각각 35.4~61.8 및 29.7~50.8을 나타내어 헴프씨드 오일과 쉽게 구분 가능하였다. 상기의 방법은 헴프씨드 오일에 여타의 식물성 유지류를 혼합하는 경우에도 혼합 여부 판별에 이용 가능하였다.

• 폴리머
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• 제37권1호
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• pp.5-14
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• 2013

본 연구에서는 UVB-313(자외선 파장 290-315 nm) 노출 하에 smooth HDPE 지오멤브레인과 flexible PP 지오멤브레인에 대한 자외선 노출의 영향을 평가하였다. 인장특성, 용융지수, 표준 및 고압 산화유도시간 및 FTIR/ATR 결과들을 고찰하였다. 노출된 지오멤브레인 시료의 인장특성은 변하지 않았지만, HDPE 지오멤브레인보다 flexible PP 지오멤브레인의 경우 산화방지제의 감소가 더 큼을 알 수 있었다. 대표적인 현장온도 $20^{\circ}C$에서의 산화방지제의 수명을 예측하기 위하여 외삽에 의한 Arrhenius 모델을 적용하였다. 자외선 노출 전후의 HDPE 지오멤브레인 시료는 용융지수의 큰 차이는 없었지만 flexible PP 지오멤브레인은 가교발생으로 인한 용융지수 감소가 발생하였다. FTIR 스펙트럼으로부터 자외선에 노출된 시료의 경우 카르보닐기와 관련된 $1750\;cm^{-1}$ 부근에서 작은 피크가 발견되었으며, 이는 산화가 진행되었음을 예시하고 flexible PP 지오멤브레인의 경우 $3100{\sim}3500\;cm^{-1}$에서 하이드록시기 또는 하이드로퍼옥사이드기에 의한 새로운 피크를 확인할 수 있었다.

• Advances in materials Research
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• 제2권1호
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• pp.51-64
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• 2013

Enantioselective macromer of trimesic acid was prepared using S(-) menthol with trimesoyl chloride on polyimide (PI) ultrafiltration membrane. The chemical composition of macromer as well as polyimide ultrafiltration membrane was determined by ATR-FTIR Spectroscopy. The optical resolution of chiral alcohols was performed in pressure driven process. The effect of monomer solutions concentration, effect of air-drying time of S(-) menthol solution, effect of reaction time, effect of operating pressure, effect of feed concentration of racemate on the performance of macromer was studied. The synthesised material exhibits separation of chiral alcohols (menthol ~23% and sobrelol ~21%).

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 추계학술대회
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• pp.134-137
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• 1995

Studies on the formulations of the additives such as antioxidants, crosslinking agent, and trans-stilbeneoxide (StO) with polypropylene (PP) have been carried out to improve the resistance of gamma radiation sterilization. The irradiated PP and ethylene-propylene copolymers samples with control and additives were characterized by mechanical tester, colorimetry, and Fourier transform infrared spectroscopy with total attenuated reflectance mode (FTIR-ATR). Crosslinking agent and StO formulated PP showed remarkable radiation resistance and minimum discoloration. Also, radiation resistance of ethylene propylene copolymers with 3% of ethylene contents was better than that of PP homopolymers in the case of no additives. The proposed mechanisms of radiation stabilization with additives are also discussed.

• Journal of Electrochemical Science and Technology
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• 제11권1호
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• pp.41-49
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• 2020

In this study poly(carbazole) films deposited on stainless steel have been investigated as electrode material for supercapacitor applications. Poly(carbazole) films were electrodeposited using cyclic voltammetry in presence of lithium, sodium and tetrabutylammonium perchlorate salts. Poly(carbazole) films doped with perchlorate anions having different counter cations were characterized by SEM, ATR-FTIR and solid state conductivity measurements. Capacitive behaviours of PCz coated steel electrodes were tested by cyclic voltammetry, charge-discharge analysis and electrochemical impedance spectroscopy. It was found that counter cation of the dopant is significantly effective on the capacitive performance on the obtained PCz films and the PCz film synthesized from lithium perchlorate has the better capacitive performance than the poly(carbazole)s synthesized from sodium perchlorate and tetrabutylammonium perchlorate salts.

• Macromolecular Research
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• 제14권6호
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• pp.617-623
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• 2006

In order to achieve an oriental lacquer (OL) film with a thick consistency, UV-curable silicone acrylate (SA) was added to OL by a dual curing process. The addition of 5 wt% UV-curable SA to the OL fomulation enabled the preparation via a single drying step of a $77{\mu}m-thick$ film exhibiting excellent surface properties. FTIR-ATR was used to investigate the effect of UV-curable SA on the behavior of film formation during curing, and the relaxation behavior of the produced films was investigated by dielectric spectroscopy. Dielectric properties were measured in the frequency range $10^{-2}-10^5\;Hz$ at various temperatures between -100 and $200^{\circ}C$. The results demonstrated that OL modified by UV-curable SA has a higher glass transition temperature and stronger secondary relaxation at a lower temperature than the conventional OL system. The OL film modified with UV-curable SA was presumed to be harder at the surface and tougher than conventional OL film.

• Macromolecular Research
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• 제11권5호
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• pp.311-316
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• 2003

The kinetics of photoinitiated polymerization of dimethacrylate macromonomers have been studied to determine the diffusion-controlled reaction parameters using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). A predicted kinetic rate expression with a diffusion control factor was employed to estimate an effective rate constant and to define the reaction-controlled and diffusion-controlled regimes in the photopolymerization. An effective rate constant, k$_{e}$, can be obtained from the predicted kinetic rate expression. At the earlier stages of polymerization, the average values of kinetic rate constants do not vary during the reaction time. As the reaction conversion, $\alpha$, reaches the critical conversion, $\alpha$$_{c}$, in the predicted kinetic expression, the reaction becomes to be controlled by diffusion due to the restricted mobility of dimethacrylate macromonomers. A drop in value of effective rate constant causes a drastic decrease of reaction rate at the later stages of polymerization. By determining the effective rate constants, the reaction-controlled and diffusion-controlled regimes were properly defined even in the photopolymerization reaction system.m.m.

• Membrane and Water Treatment
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• 제11권2호
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• pp.131-139
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• 2020

The current study focused on the preparation of low-cost PVC-based adsorbing membrane. Metakaolin, as available adsorbent, was embedded into the PVC matrix via solution blending method. The as-prepared PVC/metakaolin mixed matrix membranes were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), pure water permeability and contact angle measurements. The results confirmed the improvement of PWP and hydrophilicity due to the presence of metakaolin in the PVC matrix. Additionally the structure of PVC membrane was changed due to the incorporation of metakaolin in the polymer matrix. The static adsorption capacity of all samples was determined through dye removal. The effect of metakaolin dosage (0-7%) and pH (4, 8, 12) on dye adsorption capacity was investigated. The results depicted that the highest adsorption capacity was achieved at pH of 4 for all samples. Additionally, adsorption data were fitted on Langmuir, Freundlich, and Temkin models to determine the appropriate governing isotherm model. Finally, the dynamic adsorption capacity of the optimum PVC/metakaolin membrane was studied using dead-end filtration cell. The dye removal efficiency was determined for pure PVC and PVC/metakaolin membrane. The results demonstrated that PVC/metakaolin mixed matrix membrane had a high adsorption capacity for dye removal from aqueous solution.

• 한국전기전자재료학회논문지
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• 제19권9호
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• pp.868-872
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• 2006

In this work, the effects of the corona treatment on surface properties of semiconducting silicone rubber were investigated in terms of contact angles, ATR-FTIR(Attenuated total reflection fourier transform infrared spectroscopy) and XPS(X-ray photoelectron spectroscopy). And the adhesive characteristics were studied by measuring the T-peel strengths. Based on chemical analysis, the surface modification can be mainly ascribed to the creation of chemically active functional groups such as C-O, C=O and C-OH on semiconducting silicone surface. This oxidized rubber layer is inorganic silica-like structure of Si bound with three to four oxygen atoms ($SiOx,\;x=3{\sim}4$. The Corona treatment produces an increase in joint strength that is maximum for 10 min treatment. However, due to brittle property of this oxidized layer, the highly oxidized layer from too much extended treatment could be act as a weak point, decreasing the adhesion strength.