In this study, we have fabricated the phenolic resin (PR)/polyacrylonitrile (PAN) blend-derived core-sheath nanostructured carbon nanofibers (CNFs) via one-pot solution electrospinning. The obtained core-sheath nanostructured carbon nanofibers were further treated by mixed salt activation process to develop the activated porous CNFs (CNF-A). Compared to pure PAN-based CNFs, the activated PR/PAN blend with PR 20% (CNF28-A)-derived core-sheath nanostructured CNFs showed enhanced specific capacitance of ~ 223 F g− 1 under a three-electrode configuration. Besides, the assembled symmetric CNF28-A//CNF28-A device possessed a specific capacitance of 76.7 F g− 1 at a current density of 1 A g− 1 and exhibited good stability of 111% after 5,000 galvanostatic charge/discharge (GCD) cycles, which verifies the outstanding long-term cycle stability of the device. Moreover, the fabricated supercapacitor device delivered an energy density of 8.63 Wh kg− 1 at a power density of 450 W kg− 1.

Abstract In the present study, the effect of nickel nitrate addition as a catalytic precursor for the in situ formation of Ni nanoparticles during the heating process has been investigated on the modification of microstructure and graphitization of amorphous carbon resulting from pyrolysis of phenolic resin. For this purpose, the prepared resin samples were cured in carbon substrate with and without additives at temperatures of 800, 1000, and 1250 °C. XRD, FESEM, and TEM studies were performed to investigate the phase and microstructural changes in the samples during the heating process. In addition to phase and microstructural studies, thermodynamic calculations of the reactions performed for the in situ formation of nickel nanoparticles and their effective factors during the curing process were performed. The results indicated that nickel nitrate is transformed to nickel nanoparticles of different sizes during the reduction process in a reduced atmosphere. The in situ formation of nickel nanoparticles and its catalytic effect led to the graphitization of carbon resulting from the pyrolysis of phenolic resin at a temperature of 800 °C and above. By increasing temperature, the morphology of the formed graphite changed and hollow carbon nanotubes, carbon cells, and onion skin carbon were formed in the microstructure. It was also observed that by increasing the temperature and the amount of additive, carbon nanotubes and their size are increased. A noteworthy point from thermodynamic calculations during the formation of nickel nanoparticles was that the nickel nanoparticles themselves acted as accelerators of nickel oxide reduction reactions and the formation of nickel nanoparticles. This increases the amount of amorphous carbon graphitization resulting from the pyrolysis of phenolic resin which leads to the formation of more carbon nanotubes at higher temperatures.

Macro-porous carbon foams are fabricated using cured spherical phenolic resin particles as a matrix and furfuryl alcohol as a binder through a simple casting molding. Different sizes of the phenolic resin particles from 100– 450 μm are used to control the pore size and structure. Ethylene glycol is additionally added as a pore-forming agent and oxalic acid is used as an initiator for polymerization of furfuryl alcohol. The polymerization is performed in two steps; at 80oC and 200oC in an ambient atmosphere. The carbonization of the cured body is performed under Nitrogen gas flow (0.8 L/min) at 800oC for 1 h. Shrinkage rate and residual carbon content are measured by size and weight change after carbonization. The pore structures are observed by both electron and optical microscope and compared with the porosity results achieved by the Archimedes method. The porosity is similar regardless of the size of the phenolic resin particles. On the other hand, the pore size increases in proportion to the phenol resin size, which indicates that the pore structure can be controlled by changing the raw material particle size.

유리섬유 번들의 인장강도와 복합재료의 매트릭스수지인 페놀수지와의 접착성을 향상시키기 위하여 관능기를 가진 실란 커플링제와 페놀 수지를 이용하여 표면을 개질하였다. 일반적으로 보강재인 유리섬유의 표면을 화학적으로 개질하므로 복합재료의 특성을 조절할 수 있다. 본 연구에서는 에폭시계인 glycidyltrimethoxysilane(G-silane)과 아미노계 aminopropyltriethoxysilane (A-silane)과 페놀 수지를 사 용하여 여러 농도와 온도에서 유리섬유 표면에 1단계 처리 및 2단계 복합처리를 수행하였다. 이 때 열처 리 조건이 인장강도를 향상시키는 데 가장 중요하였다. 즉 170oC에서 처리된 유리섬유의 인장강도가 10.05 gf/D로 최대를 나타내었다. 개질 후의 유리섬유 표면은 전자현미경과 적외선분광법을 이용하여 분 석하였다. 실란의 종류와 처리 조건에 따른 유리 섬유 기계적 강도에 관한 영향도 고찰하였다.

Activated carbon spheres (ACS) were prepared at different heating rates by carbonization of the resole-type phenolic beads (PB) at 950℃ in N2 atmosphere followed by activation of the resultant char at different temperatures for 5 h in CO2 atmosphere. Influence of heating rate on porosity and temperature on carbon structure and porosity of ACS were investigated. Effect of heating rate and temperature on porosity of ACS was also studied from adsorption isotherms of nitrogen at 77 K using BET method. The results revealed that ACS have exhibited a BET surface area and pore volume greater than 2260 m2/g and 1.63 cm3/g respectively. The structural characteristics variation of ACS with different temperature was studied using Raman spectroscopy. The results exhibited that amount of disorganized carbon affects both the pore structure and adsorption properties of ACS. ACS were also evaluated for structural information using Fourier Transform Infrared (FTIR) Spectroscopy. ACS were evaluated for chemical composition using CHNS analysis. The ACS prepared different temperatures became more carbonaceous material compared to carbonized material. ACS have possessed well-developed pores structure which were verified by Scanning Electron Microscopy (SEM). SEM micrographs also exhibited that ACS have possessed well-developed micro- and meso-pores structure and the pore size of ACS increased with increasing activation temperature.

반응성 페놀수지 폐액을 처리하기 위해 중공사막 모듈을 이용한 투과증발 막 탈수공정을 연구하였다. 이 공정의 거동을 예측하기 위한 모사모델을 확립하였고 여기에 사용되는 중요 기본 파라메타들을 평판형 막을 사용하여 직접 구하여 사용함으로써 공정모사의 정확성을 얻을 수가 있었다. 이들을 모사치와 중공사 투과증발 막으로 부터 직접 측정한 각 투과특성들을 비교한 결과 서로 잘 일치함을 보여 본 모사모델의 타당성을 입증하였다. 사용된 중공사막은 중공사 안쪽에 활성층이 도포되어 있으며 공급액은 중공사 내부로 공급하였다. 공급액의 막내에서의 흐름속도에 따라 온도분포가 결정되며 이에 따라 막 투과특성이 달라짐을 모사결과로부터 얻을 수가 있었다. 공급액 온도증가는 막을 통한 탈수 투과 속도를 증가시킬 뿐 아니라 반응속도 증가로 인하여 물 생성속도도 증가시킴으로써 공급액 저장조 내의 수분 함량은 이들 상반된 공정들에 의해 결정이 됨을 보였다. 투과압력이 공급액 증기압보다 훨씬 작은 범위에서 증가할 경우 투과추진력인 공급액과 투과부의 투과물 활성도비 감소가 크지 않아 투과특성을 약간 저하시킨다. 그러나 투과압력이 공급액의 증기압에 접근할 경우 활성도비 감소가 현저하게 일어나 투과특성저하가 급격히 일어난다.

Granular Activated Carbon (GAC) has been proven to be an excellent material for many industrial applications. A systematic study has been carried out of the kinetics of physical as well as chemical activation of phenolic resin chars. Physical activation was carried out using CO2 and chemical activation using KOH as activating agent. There are number of factors which influence the rate of activation. The activation temperature and residence time at HTT varied in the range 550~1000℃ and ½~8 hrs respectively. Kinetic studies show that the rate of chemical activation is 10 times faster than physical activation even at much lower temperature. Above study show that the chemical activation process is suitable to prepare granular activated carbon with very high surface area i.e. 2895 m2/g in short duration of time i.e. 1 to 2 hrs at lower temperature i.e. 750℃ from phenolic resins.

A series of micro- and mesoporous activated carbons were prepared from two kinds of phenolic resin using a metal treated chemical activation methodology. N2-adsorption data were used to characterize the surface properties of the produced activated carbons. Results of the surface properties and pore distribution analysis showed that phenolic resin can be successfully converted to micro- and mesoporous activated carbons with specific surface areas higher than 973 m2/g. Activated carbons with porous structure were produced by controlling the amount of metal chlorides (CuCl2). Pore evolvement depends on the amount of additional metal chloride and precursors used. From the SEM and EDX data, copper contents were shown to be most effected by the incremental addition of metal chloride.

In polymer precursor based activated carbon, the structure of starting material is likely to have profound effect on the surface properties of end product. To investigate this aspect phenolic resins of different types were prepared using phenol, mcresol and formaldehyde as reactants and Et3N and NH4OH as catalyst. Out of these resins two resol resins PFR1 and CFR1 (prepared in excess of formaldehyde using Et3N as catalyst in the basic pH range) were used as raw materials for the preparation of activated carbons by both chemical and physical activation methods. In chemical activation process both the resins gave activated carbons with high surface areas i.e. 2384 and 2895 m2/g, but pore size distribution in PFR1 resin calculated from Horvath-Kawazoe method, contributes mainly in micropore range i.e. 84.1~88.7 volume percent of pores was covered by micropores. Whereas CFR1 resin when activated with KOH for 2h time, a considerable amount (32.8%) of mesopores was introduced in activated carbon prepared. Physical activation with CO2 leads to the formation of activated carbon with a wide range of surface area (503~1119 m2/g) with both of these resins. The maximum pore volume percentage was obtained in 3-20 a region by physical activation method.

Composite adsorbents were prepared by mixing water plant sludge with phenolic resin having the ratio of 1 : 1, 1 : 2, and 1 : 3 respectively, curing from 100℃ to 170℃ under N2 atmosphere, and then activating with N2 at 700℃. Thermal property, specific surface area and morphology of the composite adsorbents as well as their precursors were measured by TGA, BET and SEM respectively. Removal efficiency of the composite adsorbents to NH4+ and TOC was compared with those of commercial zeolite and activated carbon. The adsorbents presented very promising TOC removal efficiency of 98%, which was identical level to that of commercial activated carbon while they displayed removal efficiency, only 32%, of NH4+. Therefore, this composite adsorbent considered as the alternative material of commercial activated carbon, used as an expensive removal agent of organic substances and THM in water treatment plant and it also suggested a possibility of practical application in other processes.

The present research was undertaken to evaluate the possibility of water purification filter with activated carbon fibers (ACFs) using a very low cost precursor consisting of phenolic resin coated on glass fibers. The simplified procedure involving coating, curing and activation and a very low cost glass fiber as a raw material were adopted in order to reduce manufacturing cost. The breakthrough curves of the manufactured ACFs and the commercial activated carbon (AC, Calgon F-200) were investigated in the initial concentration range from 19 to 49 ppm for benzene, toluene and ethylbenzene. From breakthrough profiles, the manufactured ACFs had significantly faster adsorption kinetics than the AC. Especially the benzene breakthrough curves, the manufactured ACF (13 g of ACF with 32% of carbon on the glass) was over the limited level (5 ppb) after flowing of 32 l at initial concentration of 15 ppm, while the commercial AC was shown about 3 ppm in initial adsorption.

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.

The objective of this study is to manufacture an efficient activated carbon fiber (ACF) assemblies filter. Cellulose acetate and phenolic resin were dissolved in acetone and coated on a 2 cm-long and 2 cm-wide stainless steel mesh. Various concentrations of cellulose acetate and phenolic resin in acetone solution were examined for the extent of coating on the stainless steel mesh using a thermogravimetric analyzer (TGA), a surface area analyzer (BET) and a microscope. As a result, the best quality of coating on the stainless steel mesh was obtained with 2 wt,% cellulose acetate and 10 wt,% phenolic resin in acetone solution. The ACF filter was also impregnated with ZnCl2, KOH, H3PO4 and Na2CO3, respectively to enhance its adsorption capacity. Iodine number increased by impregnating with the chemical compound in the following order: KOH > ZnCl2> Na2CO3> H3PO4. Iodine numbers for the ACF filters impregnated with ZnCl2 (ACFz) and KOH (ACFK) were found to be 972 ~ 1,117 mg/g and 987 ~ 1,183 mg/g respectively.