• Carbon letters
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• 제3권1호
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• pp.33-38
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• 2002

Petroleum based isotropic pitch was spun into short fiber by melt-blown spinning technology. The processing parameters chosen were air velocity, die temperature, and throughput rate of the pitch within the ranges of experimental tolerances. The fiber diameter was reduced to $6{\mu}m$ by increases of hot air velocity, and spin die temperature. Also, the fiber diameter was strongly dependent on the throughput rate of the pitch and jet speed of hot air through the spinnerets. Even fibers with $10{\mu}m$ diameter were produced at throughput rate of $0.17g/min{\cdot}hole$ and at die temperature of $290^{\circ}C$.

• Carbon letters
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• 제2권3_4호
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• pp.170-175
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• 2001

A petroleum-based isotropic pitch fiber spun by melt-blown method was oxidized in air flow at various conditions. The oxidized pitch fiber obtained was tested for its infusibility and its elemental composition during the process of stabilization. The structural changes were traced by using solvent solubility, FT-IR spectroscopy, and elemental analysis. The samples showed a gradual increase in weight with increasing the oxidization temperature. The weight gain of sample oxidized at $320^{\circ}C$ for 10 min was about 4.5%. The concentration of the pyridine and toluene soluble fraction decreased with an increase in stabilization temperatures. The oxygen uptaken in the stabilization process converted aliphatic side chains into the carbonyl groups. As stabilization proceeded, the more ether and carboxylic acid groups were formed through the oxidations of aldehyde and primary alcohol, and then the carboxylic acid was dehydrated to be aromatic anhydride.

• Carbon letters
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• 제3권2호
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• pp.93-98
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• 2002

Short pitch fibers were prepared from petroleum based isotropic precursor pitch by melt-blown technology. The pitch fibers were stabilized in oxidizing condition, followed by steam activations at various conditions. The fiber surface and pore structures of the activated carbon fibers (ACFs) were respectively characterized by using SEM and applying BET theory from nitrogen adsorption at 77 K. The weight loss of the oxidized fiber was proportional to activation temperature and activation time, independently. The adsorption isotherms of the nitrogen on the ACFs were constructed and analyzed to be as Type I consisting of micropores mainly. The specific surface area of the ACFs proportionally increased with the weight loss at a given activation temperature. The specific surface area was ranged 850~1900 $m^2/g$ with pores of narrow distribution in sizes. The average pore size was ranged 5.8~14.1 ${\AA}$ with the larger value from the more severe activation condition.

• Fibers and Polymers
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• 제2권4호
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• pp.178-183
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• 2001

A pitch precursor for a general purpose carbon fiber was prepared by condensation of pyrolized fuel oil (petroleum residual oil) with bromine under nitrogen blowing. such a condensation raised the softening point of the pitch from 4$0^{\circ}C$ to $265^{\circ}$ with a yield of 43%. The pitch precurosr showed an enhanced aromaticity and enlarged molecular size, which led to a reduction in molecular mobility and optical isotropy. The precursor was spun into fibers of $20\mu\textrm{m}$ diameter at a take-up speed of 700m/min. The fiber was stepwise stabilized in air and carbonized in Ar gas to obtain an isotropic carbon fiber. The carbon fiber exhibited tensile strengths of 500-800 ㎫though the fiber was formed via a crude method. The electric conductivity of the carbon fiber was relatively high, 2.2$\times$$10^2$S/cm, sufficient to be used as electrode materials.

• Carbon letters
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• 제3권3호
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• pp.146-151
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• 2002

Activated carbon fibers were prepared from the petroleum isotropic pitch and organometallic compounds. The metalsvwere dispersed uniformly in the ACFs. The specific surface area and pore size distributions of metal containing ACFsvwere measured. The mesopores of ACFs were developed by Co, Ni, and Mn metals addition and the catalytic reactivityvof ACFs'SOx removal was increased by adding Ni and Pd metals. It was found that the mesopores did not work forvthe improvement of catalytic reactivity of ACFs' SOx removal with the blank experiment using the metal removedvACFs.

• Fibers and Polymers
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• 제1권2호
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• pp.97-102
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• 2000

Pitch precursors were synthesized from coal tar(CT) and pyrolysis fuel oil(PFO, petroleum residue oil) at relatively low temperature of $250^{\circ}$, in the presence of horontrifluorideidiethyletherate complex(BFDE) as a catalyst and nitrobenzene(NB) as a co-catalyst. The softening point, nitrogen content and carbon yield increased with an increase of concentration of NB. The pitch precursors with good spinnability were prepared by removing the volatile components through $N_2$ blowing. The precursor pitches were spun through a circular nozzle, stabilized at $310^{\circ}$ and finally carbonized at $1000^{\circ}$. The optically anisotropic structure formed at the absence of NB was changed into isotropic structure, showing a decrease in size of the flow domain. The hollow carbon fiber could be prepared in the process of stabilization. The results proposed that the morphology of carbon materials could be controlled by changing the concentration of catalyst and/or co-catalyst and/or stabilization condition that affect on the mobility of molecules during carbonization.

• 공업화학
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• 제31권1호
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• pp.36-42
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• 2020

산화 공정이 피치의 열거동 특성에 미치는 영향을 규명하기 위하여 다양한 공정 온도에서 산화된 피치를 제조하였다. 피치의 열거동 특성은 thermogravimetric analysis (TGA)를 이용하여 분석하였으며, derivative thermogravimetry (DTG) 그래프 거동 변화에 따라 A (25~100 ℃), B (250~550 ℃), C (550~800 ℃) 세 구간으로 분석하였다. A 구간에서는 피치에 함유되어 있던 수분이 제거되면서 중량 감소가 발생하였다. B 구간에서 산화에 의하여 피치의 열적 안정성이 향상되었다. 이는 산화 온도가 증가할수록 피치의 방향족화도 및 분자량이 증가하였기 때문으로 판단된다. 반면, C 구간에서는 B 구간과 반대의 결과를 보였다. C 구간에서 열적 안정성이 저해된 것은 산화 공정에 의하여 피치에 도입된 C-OH, C-O-C, C=O 결합이 분해되고, 이에 의하여 발생한 산소 화합물이 피치의 연소 반응을 유도하였기 때문으로 사료된다.

• 공업화학
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• 제28권4호
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• pp.432-436
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• 2017

석유 잔사유로부터 제조된 ${\beta}$-resin 함량이 각각 다른 바인더 피치와 등방코크스를 혼합 후 압축성형을 거쳐 탄소블럭을 제조하였다. 원소분석, FT-IR 및 열중량 분석을 통하여 바인더 피치의 물리적, 화학적 특성 및 열적 거동을 각각 고찰하였다. 또한, 주사전자현미경을 이용하여 측정된 탄소블럭의 파단면으로부터 등방코크스 입자와 바인더 피치의 결합성을 평가하였다. 실험 결과로부터 바인더 피치의 ${\beta}$-resin 함량이 높을수록 코크스와 바인더의 결합성이 향상됨을 알 수 있었다. 또한, 탄소블럭의 탄화 후 밀도는 ${\beta}$-resin 함량이 1.4%에서 20.1%로 증가함으로 인하여 $1.325g/cm^3$에서 $1.383g/cm^3$으로 증가하였다.