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        검색결과 5

        1.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the aromatic carbon content of epoxy resin (EP) increased via carbon tar pitch (CTP) modification, and the CTP occurred self-polymerization reaction. The carboxyl and hydroxyl groups of CTP and the hydroxyl and carboxyl groups of EP occurred chemical cross-linking reaction. CTP and graphitization treatment promoted EP CF carbon crystal growth. The graphitization degree of pure EP CF and 40 wt% CTP modified EP CF are 8.42% and 44.21%, respectively. With the increase CTP content, the cell size, ligament junction and density of graphitization modified EP CF gradually increased, while the number of pores and cells gradually decreased. The cell size, ligament junction size and density of 40 wt% CTP modified graphitization EP CF increased to 1200 μm, 280 μm and 0.5033 g/cm3, respectively. EP CF exhibits entangling carbon ribbon and isotropic amorphous carbon. The 40 wt% CTP modified EP CF is composed of evenly distributed amorphous resin carbon and graphite domain CTP carbon. The graphitization modified EP CF improved electrical conductivity, and the electrical conductivity of 40 wt% CTP modified EP CF is 126.6 S/m. The compressive strength can be decided by EP carbon strength and its char yield, and graphitization 40 wt% CTP modified EP CF reached 4.9 MPa. This study provides some basis for preparation and application of CTP modified EP CF.
        4,000원
        2.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, Pitch-derived activated carbon (PAC) pellets were by steam activation for automotive carbon canisters. The crystal structure of PAC was analyzed using X-ray diffraction. The textural properties of PAC were studied by Brunauer– Emmett–Teller (BET), Horvath-Kawazoe (HK), and Non-Localized Density Functional Theory (NLDFT) equations with N2/ 77 K isotherm adsorption/ desorption curves. The butane adsorption capacity of the PAC pellets was analyzed according to the ASTM D5228 standard. With increasing steam activation time, the specific surface area and total pore volume of the PAC increased 650–1950 m2/ g and 0.27–1.02 cm3/ g, respectively. The mesopore ratio of PAC increased with increasing activation time and was observed up to 28.4% at 190 min. The butane adsorption capacity of the PAC increased and was observed to range from 10.86 to 51.55%. A close relationship between butane adsorption capacity and pore size (1.47–2.39 nm) was found. Finally, the butane activity of PAC was found to be 51.55% for the steam activated at 950 ℃ for 190 min; this butane activity is 24% better than that of the coconut-derived activated carbon (41.43%) with a similar specific surface area, indicating that pitch is a suitable material for the activated carbon of automotive carbon canisters.
        4,200원
        3.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pitch precursors affording excellent spinnability, high-level oxidation-resistance, and good carbonization yields were prepared by bromination–dehydrobromination of various ratios of pyrolyzed fuel oil and coal tar pitch. The pitches exhibited spinnabilities that were much better than those of pitches prepared via simple distillation. A pitch prepared using a 1:2 ratio of fuel oil and coal tar pitch exhibited the best tensile strength. Pitch fibers of diameter 8.9 ± 0.1 μm were stabilized at 270 °C without soaking time after heating at a rate of 0.5 °C/min and carbonized at 1100 °C for 1 h after heating at 5 °C/min. The resulting carbon fibers exhibited a tensile strength, elongation, Young’s modulus, and average diameter of 1700 ± 170 MPa, 1.6 ± 0.1%, 106 ± 37 GPa, and 7.1 ± 0.2 μm, respectively.
        4,000원
        4.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To manufacture a carbon/carbon composite the coal tar pitch was used as the matrix precursor and the PAN (polyacrylonitrile)-based carbon fiber was used as the reinforcing material to weave 3-directional preform. For pressure carbonization HIP equipment was used to produce a maximum temperature of 1000℃ and a maximum pressure of 100 MPa. The carbonization was induced by altering the dwell temperature between 250℃ and 420℃, which is an ideal temperature for the moderate growth of the mesophase nucleus that forms within the molten pitch during the pressure carbonization process. The application of high pressure during the carbonization process inhibits the mesophase growth and leads to the formation of spherical carbon particles that are approximately 30 nm in size. Most particles were spherical, but some particles were irregularly shaped. The spread of the carbon particles was larger on the surface of the carbon fiber than in the interior of the matrix pocket.
        4,000원
        5.
        1996.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 정속마찰 시험기를 사용하여 공기중에서 핏치/CVI계와 페놀/CVI계 낱소/탄소 복합재료의 마찰특성을 평가하고 상호 비교하였다. 운용조건(마찰거리, 마찰속도, 마찰압력)에 관계없이 페놀/CVI계의 평균 마찰계수가 핏치/CVI계 보다 높은 값을 나타내었다. 마찰거리가 4Km이하 일때는 평균 마찰계수가 불안정한 경향을 나타내고 그 이후에서는 안정한 평균 마찰계수 값을 갖는다. 또한 마찰속도와 마찰압력이 증가할수록 평균 마찰계수는 감소하는 경향을 나타내며, 페놀/CVI계의 평균 마찰계수가 핏치/CVI계 보다 높고 마찰면 온도 상승률과 최대 마찰면 온도도 높다. 마찰계수는 마찰면 온도의 영향을 받으며, 마찰속도와 3kg/cm2이하에서 마찰압력이 커질수록 최대 마찰계수를 갖는 마찰면 온도는 높아진다.
        4,000원