• 한국세라믹학회지
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• 제33권7호
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• pp.816-822
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• 1996

서로 다른 흑연화도를 갖는 furan 수지로 부터 얻어진 무기화합물(SiC, TiO2) 첨가 탄소재료의 산화반응의 흑연구조 의존성에 대하여 살펴보았다. 탄소재료의 산화는 시료의 표면적에 크게 의존하여, 흑연화가 상당히 진행된시료라 할지라도 표면적이 클 때는 살화속도도 빠른 것으로 밝혀졌으며, 단위 중량이 아닌 단위면적당의 산화속도로 바꿔 생각했을 때 흑연화가 진행될 수록 산화반응도 늦어지는 것을 알 수 있었다. 그리고 겉보기 활성화 에너지값으로 부터 생각할 때 흑연(TiO2 첨가시료)과 난층흑연(SiC 첨가시료)이 동일한 반응기구에 의해 산화가 진행되는 것으로 판단되었다. 또한 두종류 이상의 결정구조가 혼재하여 있는 시료의 경우 이들 성분들의 산화속도는 달라 반응의 초기에 흑연으로 결정화된 않은 비정질 탄소 성분이 흑연 성분보다 먼저 선택적으로 산화되는 것을 알 수 있었다.

• Carbon letters
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• 제8권2호
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• pp.95-100
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• 2007

A series of activated carbons (ACs) were derived from sugarcane bagasse under two activation schemes: steam-pyrolysis at $600-800^{\circ}C$ and chemical activation with $H_3PO_4$ at $500^{\circ}C$. Some carbons were treated at 400, $600^{\circ}C$, or for 1-3 h, and/or in flowing air during pyrolysis of acid-impregnated mass. XRD profiles displayed two broad diffuse bands centered around $2{\theta}=23$ and $43^{\circ}$, currently associated with diffraction from the 002 and 100/101 set of planes in graphite, respectively. These correspond to the interlayer spacing, Lc, and microcrystallite lateral dimensions, La, of the turbostratic (fully disordered) graphene layers. Steam pyrolysis-activated carbons exhibit only the two mentioned broad bands with enhancement in number of layers, with temperature, and small decrease in microcrystallite diameter, La. XRD patterns of $H_3PO_4$-ACs display more developed and separated peaks in the early region with maxima at $2{\theta}=23$, 26 and $29^{\circ}$, possibly ascribed to fragmented microcrystallites (or partially organized structures). Diffraction within the $2{\theta}=43^{\circ}$ is still broad although depressed and diffuse, suggesting that the intragraphitic layers are less developed. Varying the conditions of chemical activation inflicts insignificant structural alterations. Circulating air during pyrolysis leads to enhancement of the basic graphitic structure with destruction and degradation in the lateral dimensions.

• Carbon letters
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• 제7권4호
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• pp.277-281
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• 2006

In this study, in order to easily provide functional groups on the surface of carbon nanotubes, dual structural multiwalled carbon nanotubes which have crystalline graphite and turbostratic carbon wall were synthesized by modified vertical thermal decomposition method. Synthesized dual structural MWCNTs were characterized by FE-SEM, TGA, HR-TEM, Raman spectroscopy and BET specific surface area analyzer. The average innermost and outermost diameters of the synthesized nanotubes were around 45 and 75 nm, respectively. The large empty inner space and the presence of graphitic carbons on the surface may open potential applications for gas storage and collection of hazardous materials.