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탄화규소의 전구체로서 Polycarbosilane 의 합성 및 물성 비교 연구
문교태,민동수,임헌성,김동표 ( Kyo Tae Moon,Dong Soo Min,Heun Soung Lim,Dong Pyo Kim ) 한국공업화학회 1998 공업화학 Vol.9 No.2
Dichlorodimethylsilane의 탈염소중합반응에의해 polydimethylsilane(PDMS)을 합성한 후 가압 반응기내의 재배열 반응에 의해 탄화규소(SiC) 전구체인 polycarbosilane(PCS)를 합성하였다. 합성된 PCS는 n-hexane과 methanol의 혼합용매를 사용한 분별 침전법으로 분자량에 따라 세 분율로 분리한 다음 FT-IR, NMR, GPC, TGA/DSC와 XRD를 사용하여 분석한 뒤 상업용 고분자와 비교하였다. 또한 합성된 PCS의 분자량 분포는 반응 압력, 반응 온도 및 시간에 대한 의존성을 가지며 분자량에 따라 고분자의 열적성질과 세라믹 수율이 달라짐을 알 수 있었다. PDMS를 420℃에서 10시간 동안 반응시킬 때 비교적 단분산 분자량 분포를 가지며, 저분자체와 비용해성 PCS가 최소로 생성되고 우수한 가공성을 가진 중간 분자량 분포(M_n=4,000)PCS가 최대로 얻어졌다. Polycarbosilane(PCS) as a SiC precursor was synthesized from the rearrangement reaction of polydimethysilane(PDMS) in an autoclave, which was prepared by dehalocoupling reaction of dichlorodimethylsilane. After fractional precipitation into three fractions in n-hexane-methanol mixture, they were characterized by FT-IR, NMR, GPC, TGA/DSC and XRD, and compared with the commercial product. We found that the molecular weight distributions of the PCS depended on the reaction pressures, temperatures and the reaction times, and affected thermal property and ceramic yield of the polymer. The monodispersed PCS containing less amount of oligomers and nonsoluble products was prepared by reaction of PDMS at 420℃ for 10 hrs, and it also gave the greatest amount of medium molecular weight(M_n=4,000) fraction. v
Primer와 과산화수소를 함유한 자가 미백 부착대의 미백 효과에 대한 실험실 실험 연구
김종훈 ( Jong Hoon Kim ),문교태 ( Kyo Tae Moon ),김지혜 ( Ji Hye Kim ),안재현 ( Jae Hyun Ahn ) 한국치위생과학회 2014 치위생과학회지 Vol.14 No.2
The purpose of this study was to evaluate the tooth whitening efficacy of 2.9% hydrogen peroxide strip with primer gel of alkaline condition and containing metallic salts as catalyst in-vitro. Hydroxyapatite (HAP) disk was made by compressing and sintering 0.3 g of mixture of HAP powder and polyvinyl alcohol. This HAP disk was stained using modified Stookey.s methods. Main bleaching materials were 2.9% hydrogen peroxide strips and the primer gel containing metallic salts as catalyst and pH controller. Stained HAP disks were allocated to each control or experimental groups by color grade. Stained HAP disks were treated for 30 minutes in 37oC/80% incubator for wetting, then each primer gel according to control or each test group was spread and strips were attached. After 30 minutes for each group strips were detached and HAP disks were washed, dried then color was measured by colorimeter. Efficacy was evaluated by comparing ΔL values of HAP disks at baseline and after treated. Among some kinds of metallic salts for as catalyst, ferric chloride showed best improvement of efficacy and it was statistically significant (p<0.05) compared to control group. Evaluating whitening efficacy according to various pH of primer, efficacy using primer of alkaline condition was increased significantly (p<0.05) compared to control and primers of acidic or neutral conditions. Evaluating whitening efficacy for time course, efficacy of test group for 30 minutes was similar to that of control for 120 minutes. It can be concluded that 2.9% hydrogen peroxide strips using with primer of alkaline condition and containing ferric chloride showed significantly increased whitening efficacy compared to the case of strips only.
Curcuma xanthorrhiza 추출물 및 함유 치약의 구취 억제 효과와 구강 유해균에 대한 선택적 항균 효과
김백일 ( Baek Il Kim ),김상년 ( Sang Nyun Kim ),장석윤 ( Sug Youn Chang ),문교태 ( Kyo Tae Moon ),김윤석 ( Yun Seog Kim ),황재관 ( Jae Kwan Hwang ),정승화 ( Seung Hwa Jeong ),김민영 ( Min Young Kim ),김해선 ( Hae Sun Kim ),권호근 대한예방치과·구강보건학회 2005 大韓口腔保健學會誌 Vol.29 No.2
법랑질 초기우식병소에서 1,500 ppm 불소함유치약의 재광화효과
김애옥 ( Ae-ok Kim ),정성숙 ( Seong-soog Jeong ),김다은 ( Da-eun Kim ),하원호 ( Won- Ho Ha ),문교태 ( Kyo-tae Moon ),최충호 ( Choong-ho Choi ),홍석진 ( Suk-jin Hong ) 대한구강보건학회 2016 大韓口腔保健學會誌 Vol.40 No.4
Objectives: We compared the effects of a 1,500 ppm fluoride-containing toothpaste and a 1,000 ppm fluoride-containing toothpaste, which were revised up to the recent revision, and evaluated their effects on the tooth surface after adding bamboo salt to the preparations. Methods: Experimental early artificial caries specimens were subjected to one of four treatments (n=12 per treatment group): 1,500 ppm NaF, 2% bamboo salt+1,000 ppm NaF, 1,000 ppm NaF, and control treatment. The specimens were exposed to the experimental toothpaste, artificial saliva, and demineralized solution. The treated specimens were analyzed using Vickers surface hardness testing, scanning electron microscopy, and atomic force microscopy. Results: The toothpaste with a high fluoride concentration (1,500 ppm NaF) showed more remineralization than did the toothpaste with a low fluoride concentration (1,000 ppm NaF). The 2% bamboo salt+1,000 ppm NaF group showed remineralization similar to the 1,500 ppm NaF group and higher surface microhardness than the 1,000 ppm NaF group. Conclusions: Toothpastes containing 1,500 ppm NaF have a higher preventive effect against dental caries than do toothpastes containing 1,000 ppm NaF. The addition of bamboo salt to fluoride-containing dentifrices improves their effectiveness in preventing dental caries.
고분자량 Polymethylsilane 의 합성 및 촉매 가교 반응에 관한 연구
김동표,문교태,민동수 한국공업화학회 1997 응용화학 Vol.1 No.2
the use of polymethylsilane(PMS) as a ceramic precursor had a disadvantage of the lower pyrolytic yield, when the PMS transfer to SIC ceramics. The reason is the higher volatilization of PMS during the pyrolysis due to the lower molecular weight of that prepared by using the general methods. In this study, therefore, we tried to prepare the relatively higher molecular weight PMS by the variation of the mixing ratio of THF and n-hexane as a solvent and by using of the various catalysts in dehydrocoupling reaction of PMS. As the result, the higher molecular weight of PMS was obtained with the increase of the mixing ratio of THF. The use of catalysts in dehydrocoupling reaction of PMS was also increased the molecular weight of PMS. The most effective catalyst was a TiCP₂Cl₂/Red-Al, and the use of the catalyst was increased about the three times in molecular weight and the twice in pyrolytic yield of PMS.
SiC 전구체인 Polymethylsilane 을 이용한 SiC / MoSi2 복합상 제조
김동표,문교태,민동수 한국공업화학회 1998 응용화학 Vol.2 No.1
Silicon polymer, polymethylsilane, as a SiC precursor was synthesized and then mixed with metal compounds. They were converted to various ceramic composites on heating to temperature 1450℃. ultrasonic suspension of 7wt% or l5wt% Mo metal powder in PMS and the mixture of 3wt% MoCl_5 and PMS were transformed to pure Sic/Mosi₂ceramics. However, when used Mo(CO)_6 as a Mo source, the mixtures of SiC, small amount MoSi₂, and other phases were produced.
서신석,김동표,문교태,노재성 忠南大學校 産業技術硏究所 1997 산업기술연구논문집 Vol.12 No.1
Cordierite ceramic was prepared by sol-gel method. It was analyzed by Infrared spectroscopy and X-ray diffraction patterns that the ceramic was chemically mixed in molecular level and transformed to α-cordierite at 1250℃. Water vapour treatments for aging and drying process were conducted to get porous cordierite with thermally stable pore structure. It resulted in 220-410㎡/g BET surface area and mesoporous structure with mean pore diameter, 40Å. Compared to naturally dried ceramic, the ceramic showed superior thermal stability of surface area up to 700℃.