http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Carbon nanofiber from deacetylated cellulose acetate prepared by direct fluorination
김민일,김민지,이상민,임지선,이영석 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0
In this study, cellulose based carbon nanofiber has been fabricated by electrospinning from cellulose acetate (CA) followed by fluorination and carbonization at 800 ℃ for 1 h. The properties of the fluorinated electrospun CA nanofibers have been analyzed by scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS) and thermo-gravimetric analysis (TGA). Fluorine functional group in CA nanofiber is introduced by fluorination which has caused deacetylation on cellulose acetate fiber. This deacetylation of CA fiber has prevented from melting of cellulose acetate during carbonization process. The introduced fluorine functional groups have also increased thermal stability and carbonization yield of CA fiber.
Effect of nitric acid treatment on the pitch properties and preparation of activated carbon
김민일,배병철 한국탄소학회 2022 Carbon Letters Vol.32 No.1
The pore structure of pitch-based activated carbon prepared by physical activation was improved by nitric acid treatment of pitch. The nitric acid treatment introduced oxygen and nitrogen functional groups on pitch, and increased pitch molecular weight by cross-linking. The introduced oxygen and nitrogen functional groups on pitch were removed during the carbonization process, so they did not directly affect the physical activation process. The increased pitch molecular weight induced an increase of the pitch softening point. The increased softening point prevented rearrangement between the pitch molecules during the carbonization process, thereby inhibiting the orientation improvement of pitch molecules. The crystal degree of the carbonized pitch was reduced due to the inhibition of the orientation improvement. The reduced crystal degree increased reactivity between carbonized pitch and activation agent (CO2) and formed micropores, so that activated carbon with a high specific surface area could be prepared.
Thermal stability enhancement of lyocell fiber by gas phase fluorine treatment
김민일,김민지,이상민,이영석 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
Lyocell fiber was treated with gas phase fluorine for increasing thermal stability. The properties of gas phase fluorine treated lyocell fibers were analyzed by FT-IR, XPS and TGA. Integral procedure decomposition temperature (IPDT) and initial decomposition temperature (IDT) were calculated from TGA. Increasing of gas phase fluorine treatment temperature was increased the fluorination functional groups on lyocell fiber. The IPDT of lyocell fibers was increased and IDT was decreased depending on increasing of fluorine functional group. In this study, the IPDT of fluorinated cellulose fibers at 120°C was increased 60.8% compared to pure cellulose fibers.
The effect of fluorine functional groups on carbonization of cellulose fibers
김민일,김도영,김민지,임지선,이영석 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1
Fluorine functional groups in cellulose fibers were introduced by fluorination for increasing of carbonization yield. The surface functional groups and thermal properties of fluorinated cellulose fibers were analyzed by X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA), respectively. Carbonization of fluorinated cellulose fibers was accomplished in N<sub>2</sub> gas at 800 °C for 1h, and the carbonization yield was measured. The content of fluorine functional groups in fluorinated cellulose fibers was increased according to increasing of fluorination temperature. However in high fluorination temperature (at 180 °C), the content of fluorine functional groups was decreased by the high heat energy during fluorination. Introduced fluorine functional groups increases the carbonization yield of cellulose fibers by increasing of double bond (C=C bond). The carbonization yield was increased 52.5% compared to pure cellulose fibers by fluorination at 120 °C.