http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : 김동표 ( Kyo Tae Moon (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
-
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
-
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℃.
ScienceON
KISS연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
