• Polymer(Korea)
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• v.27 no.2
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• pp.91-97
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• 2003

The effect of fluorination of nanoscaled silicas on mechanical interfacial properties and thermal stabilities of the silica/polyurethane composites was investigated. The surface properties of the silica were studied in X-ray photoelectron spectroscopy and contact angle measurements. Their mechanical interfacial properties and thermal stabilities of the composites were characterized by tearing energy and decomposition activation energy, respectively. As experimental results, the London dispersive component of surface free energy and fluorine functional groups of silica surfaces were increased as a function of fluorination temperature resulting in improving the trearing energy ($G_{IIIC}$) of the composites. Also, the thermal stabilities of the composites were increased as the treatment temperature increases. These results could be explained that the fluorine functional groups on silica surfaces played an important role in improving the intermolecular interactions at interfaces between silicas and polyurethane matrix in a composite system.

• Polymer(Korea)
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• v.37 no.3
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• pp.316-322
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• 2013

In this study, poly(ethylene terephthalate) (PET) was treated with fluorination and ultrasonic washing treatment for hydrophilic modification of PET film. We measured the change of surface modified PET film surface characteristics using contact angle, surface free energy, FE-SEM, AFM and XPS. After direct fluorination and ultrasonic washing treatment, the water contact angle was measured to be $10.81^{\circ}$, 85% reduction compared to the untreated PET film. Total surface free energy has been measured to be $42.25mNm^{-1}$, 650% increase compared to the untreated PET film. Also RMS roughness has been measured to be 1.965 nm, 348% increase compared to the untreated PET film. Hydrophilic functional group C-OH bond concentration has increased approximately 3 times. These results are attributed to the hydrophilic functional group and cavitation due to chemical etching. From this result, it was suggested that the fluorination-ultrasonic washing treatment method could be useful to make PET film surface hydrophilic.

• Journal of dental hygiene science
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• v.10 no.4
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• pp.295-300
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• 2010

The aim of this study were to elucidate effects of fluoridated bleaching agents and post-treatment fluoride application on the color and microhardness of enamel surface. Twenty freshly extracted human adult molar were each sectioned into halves, the specimens divided and treated according to four experimental groups: 1, untreated controls: 2, treatment with 10% carbamide peroxide (CP) bleaching agent; 3, treatment with 10% CP containing 0.11% fluoride; 4, treatment with 10% CP followed by a 0.9% sodium fluoride gel application. Group 2-4 were compared with the baseline data. treated 8 h per day for 14 days then immersed in distilled water for 2 weeks. Changes in enamel color and microhardness were evaluated on Days 7 and 14. All the bleached enamel specimens revealed increased whiteness and overall color value. Groups 2 and 4 showed significantly decreased enamel microhardness compared to their baseline. The specimens treated with fluoridated bleaching agents showed relatively less reduction in enamel microhardness than those treated with nonfluoridated agents during the bleaching treatment. The addition of fluoride did not impede the tooth whitening. The fluoridated bleaching agents reduced the microhardness loss of enamel.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.1
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• pp.16-23
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• 2016

Purpose: The aim of this study was to evaluate whether fluorides at various pH cause changes in the surface roughness of titanium implants that alter the adherence of bacterial biofilms. Materials and Methods: The titanium disks were assigned randomly to the following seven groups according to the fluoride agents and application time (1 minute or 30 minute) used: control (no treatment); group 1 (1.23% acidulated phosphate fluoride [APF] at pH 3.5 for 1 minute); group 2 (1.23% APF at pH 3.5 for 30 minute); group 3 (1.23% APF at pH 4.0 for 1 minute); group 4 (1.23% APF at pH 4.0 for 30 minute); group 5 (2% NaF gel at pH 7.0 for 1 minute); group 6 (2% NaF gel at pH 7.0 for 30 minute). The surface roughness of the titanium disks and the amount of adherent bacteria were measured. Results: Group 2 showed a significantly greater surface roughness than the control group (P < 0.0001). No significant differences in the amount of surface bacteria were observed between the treated samples and the controls. In addition, there were no significant differences in bacterial adherence relative to the incubation period between the treated samples and the controls. Conclusion: The surface roughness of the titanium disks was significantly greater after treatment with APF at pH 3.5 for 30 min compared with that of the controls. In addition, we found that the amount of Porphyromonas gingivalis, Fusobacterium nucleatum, and Aggregatibactor actinomycetemcomitans was similar among all groups

• Membrane Journal
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• v.17 no.4
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• pp.345-351
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• 2007

In this research, by using the fluorine gas, the poly(ether sulfone) (PES), the polysulfone (PSf), and the poly-vinylidenefluoride (PVDF) membranes were modified to improve the performance of the optional Gas-Liquid Contactor The SEM, surface contact angle, XPS, and the water transmission minimum pressure test was performed in order to examine the characteristics of which is surface modified. As a result of looking into the surface morphology of from the SEM measurement, we could know that the roughness of the membrane surface increased as the fluorine processing time increased. $-CH_2$, and the perfluoro group of $-CH_3$ were chemically combined with the surface fluorine conversion film surface and the hydrophobicity was exposed to be increased. Moreover, we could know that as the surface fluorinated processing time increased from the surface contact angle and water transmission minimum pressure test, the measured value increased and the overall characteristics were improved.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.3
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• pp.207-212
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• 2010

Purpose: Rigid gas permeable (RGP) contact lenses, based on fluorosilicone acrylate, were treated with plasma in air. Methods: The chemical compositions were analyzed by using X-ray photoelectron spectroscopy (XPS), the surface morphology and roughness of RGP contact lenses were observed by using atomic force microscopy (AFM), and the wettability changes were estimated by wetting angle measurement. Results: As the contact lenses were treated by the plasma, the F contents decreased significantly, and the O and Si contents increased on the surface. The number of oxygen-containing hydrophilic radicals (C-O and Si-O) increased greatly, the hydrophobic surface decreased, and the wetting angle increased. But the C-O bonds created with exchange of the fluorine did not increase a wettability. The surface compositions were not remarkably changed for the 6 months after plasma treatment, but the wetting angle increased again. Conclusions: It was considered that the improved wettability of the RGP contact lenses of high fluorine content after plasma treatment was affected by the activation of surface, the increase of Si-O, and the decrease of hydrophobic surface.

• Membrane Journal
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• v.20 no.2
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• pp.106-112
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• 2010

This study deals with the surface fluorination of poly(phenylene oxide) (PPO) with the direct contact of 100 ppm fluorine gas. To characterize the surface fluorinated membranes, the contac angle measurement, X-ray photoelectron microscopy analysis and the gas permeation experiments were performed. As the fluorination time increases, the hydrophobicity of membrane surfaces is increased by the surface characterization. In general, as expected, the overall gas permeability was reduced. Typically, the permeability reduction of 33% for nitrogen, 23% for oxygen and 3% for carbon dioxide were observed when the membranes were exposed in 100 ppm environment for 60 min., meanwhile the selectivity was increased from 3.92 to 4.47 for $O_2/N_2$ and 18.09 to 25.4 for $O_2/N_2$, respectively.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.4
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• pp.412-418
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• 2017

During orthodontic treatment, formation of white spot lesions (WSLs) around brackets has long been recognized as a potential risk. This study performed to investigate effect of preventing enamel demineralization and remineralization by application of fluoride-containing orthodontic primer. Fifty extracted bovine incisors teeth were randomly allocated to 3 groups: (I) Non-preparation specimens, (II) Application of Light Bond$^{TM}$ as fluoride containing orthodontic primer, (III) Application of Transbond$^{TM}$ XT Primer as traditional orthodontic primer without fluoride. Each group is demineralized under artificial carious solution. The demineralization pattern was evaluated using a Q-ray view, Vickers hardness test and polarized light microscope. The remained primer was calculated as 35 - 50%. The highest surface microhardness was shown on Light Bond$^{TM}$ surface. There were statistically significant differences in Vickers microhardness number between adjacent areas of Light Bond$^{TM}$ and non-prepared area. There was almost no demineralization of the enamel surface under the Light Bond$^{TM}$. At the adjacent site of Light Bond$^{TM}$, the shallow caries pattern and remineralization appearance were also observed. These results suggest that the use of fluoride-containing primers may be useful for bracket attachment to reduce enamel demineralization during orthodontic treatment.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.50-50
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• 2011

발수가공은 섬유표면에 낮은 표면에너지 물질을 도포하여 섬유제품에 적심 저항성을 부여하는 것으로 일반적인 방법으로는 불소계 고분자 물질을 포함한 가공제액을 부여하고 열에너지원을 사용하여 섬유 표면에 경화하여 고착시키고 처리온도는 $150{\sim}170^{\circ}C$의 범위에서 수 분 처리하지만 처리시간을 증가하면 섬유에 황변을 일으킬 수 있고 직물의 한 면에만 발수성을 구현하기가 어렵다. 피부와 접촉하는 부위에서의 불필요한 발수성은 땀 흡수저하, 알러지 발생 우려 등 쾌적성 저하 요인이 될수 있어 스포츠, 레저 의류 분야에서는 섬유제품의 일면만을 발수처리 하는 가공이 필요되어진다. 편면 발수가공을 위한 선행기술로는 상하 중 하나의 롤러에만 발수제를 묻혀 섬유제품의 일면에만 발수가공을 하는 것과 분사기로 발수제를 섬유제품의 일면에 도포하는 것 등이 있다. 하지만 일면에 처리된 발수제가 반대면으로 침투하거나 균일한 발수처리가 되지 않는 등의 문제점이 있고 발수제의 농도증가 및 증점제를 사용하여 점도를 증가시켜야하기 때문에 발수처리의 균일성 및 내구성 있는 편면발수공정이 어려운 단점이 있다. 본 연구에서는 UV경화가 가능한 불소계 발수제와 물에 용해되는 광개시제가 첨가된 수용액을 PET직물에 패딩하고 UV로 경화하여 양면 모두 발수성을 부여한 후 UV조사로 표면개질하여 표면친수성을 증가시켜 양 면의 발수성을 조절하였다.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.705-713
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• 2004

The objectives of this study were to evaluate the fluoride release and the change of surface roughness of fluoride releasing restorative materials after toothbrush-dentifrice abrasion. Seven commercially available fluoride releasing restorative materials (Fuji II LC Improved: FL, Compoglass F: CG, Dyract AP: DR, F2000: FT, Ariston: AT, Tetric: TR, and Gradia: GD) were selected as experimental materials. The results obtained were summarized as follows: 1. The AT, FL, and CF groups produce an initially large burst of fluoride release and comparatively low but continuous release of fluoride. But other groups produce no initial burst of fluoride and levels of release remain relatively constant. 2. The rate of fluoride release remains steady state after 40 days. The results of Tukey's test (P<.05), the fluoride release showed the order of decreasing rank as follows: AT > FL > compomers > TC and GD. 3. The surface roughness indicated that the highest value was observed in the FT group and the lowest value was observed in the CF group. The surface roughness of Tukey's test showed the significant differences between groups of FT, AT and FL and groups of CF, DR, GD and TC (P<0.05).