• 폴리머
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• 제26권4호
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• pp.468-476
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• 2002

순수한 PAN 섬유의 예비산화와 가수분해의 과정을 통하여 제조된 oxy-PAN은 염기와 산용액에 담그었을 때 신장과 수축 거동을 보임이 알려져 있다. 본 연구에서는, 염기 (NaOH) 용매에서 약 30%의 신장과 산 (HCl) 용매에서 30∼50%의 수축 거동을 관찰하였다. 기계적 특성에 대한 실험에서, oxy-PAN 섬유가 수축되었을 때 향상된 기계적 특성을 나타내었다. 이러한 거동과 기계적 특성은 인체의 근육과 선형 구동체의 그것들과 유사하였다. NaOH와 HCl 용액에서 oxy-PAN 섬유의 길이가 변화하는 중요한 요인으로는 친수화 또는 소수화 구조의 전환에 의한 영향이다. 다른 요인으로는 oxy-PAN 섬유와 용액간의 이온과 물의 교환, 이온의 농도차에 의한 삼투압 등이 영향을 준다. Oxy-PAN 섬유의 신장 및 수축과 기계적 특성에 영향을 미치는 여러 가지 요인들을 규명하기 위한 보다 많은 연구가 필요하지만, 본 연구실에서 제조된 oxy-PAN 섬유가 인공 근육 및 선형 구동체로 적용될 수 있는 충분한 가능성이 있음을 제시한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.159-162
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• 1998

The new type polymer electrolyte composed of polyacrylonitrile(PAN) baed polymer electrolyte contain LiClO$_4$-EC/PC and LiPF$\sub$6/-EC/PC were developed for the weightless and long or life time of lithium polymer battery system with using polyaniline electrode. The gel type electrolytes were prepared by PAN at different lithium salts in the glove box. We prepared for polymer electrolyte with knife casting method. The minimum thickness of PAN gel electrolyte for the slim type is about <400∼500$\mu\textrm{m}$. These gel electrolytes showed good compatibility with lithium electrode. The test cell of Li/polymer electrolyte/Lithium cobalt oxide solid state cell which was prepared by different lithium salt was researched by electrochemical technique. Resistance of polymer electrolyte which consist of LiClO$_4$ is more less than that of LiPF$\sub$6/ and cycle life is more longer than that of LiPF$\sub$6/.

• 공업화학
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• 제29권3호
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• pp.318-324
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• 2018

본 연구에서는 물리적 활성화법인 수증기 활성화법을 이용하여 PAN (Polyacrylonitrile)계 활성탄소섬유를 제조하였다. 활성화는 온도와 시간을 변수로 하였으며, 활성화 온도(700, 750, $800^{\circ}C$)에 도달하였을 때 200 mL/min의 수증기 유량의 조건으로 PAN 탄소섬유의 활성화를 진행하였다. 제조된 활성탄소섬유의 기공구조를 분석하기 위하여 질소가스의 흡 탈 등온선을 통한 비표면적($S_{BET}$) 측정과 표면분석을 위한 AFM 분석을 실시하였다. 또한 인장시험을 실시하여 활성화 결과 형성된 기공구조가 섬유의 기계적 특성에 미치는 영향을 고찰하였다. 그 결과, 활성화 후 섬유의 비표면적($S_{BET}$)은 $448{\sim}902m^2/g$의 값을 나타냈으며, 인장강도는 58.16~84.92%, 탄성계수는 69.81~83.89%의 감소를 보였다.

• Carbon letters
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• 제12권1호
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• pp.31-38
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• 2011

This study experimentally investigated dicyclohexylammonium 2-cyanoacrylate (CA) as a potential comonomer for polyacrylonitrile (PAN) based carbon fiber precursors. The P(AN-CA) copolymers with different CA contents (0.19-0.78 mol% in the feed) were polymerized using solution polymerization with 2,2-azobis(isobutyronitrile) as an initiator. The chemical structure and composition of P(AN-CA) copolymers were determined by proton nuclear magnetic resonance and elemental analysis, and the copolymer composition was similar to the feeding ratio of the monomers. The effects of CA comonomer on the thermal properties of its copolymers were characterized differential scanning calorimetry (DSC) in nitrogen and air atmospheres. The DSC curves of P(AN-CA) under nitrogen atmosphere indicated that the initiation temperature for cyclization of nitrile groups was reduced to around $235^{\circ}C$. The heat release and the activation energy for cyclization reactions were decreased in comparison with those of PAN homopolymers. On the other hand, under air atmosphere, the P(AN-CA) with 0.78 mol% CA content showed that the initiation temperature of cyclization was significantly lowered to $160.1^{\circ}C$. The activation energy value showed 116 kJ/mol, that was smaller than that of the copolymers with 0.82 mol% of itaconic acids. The thermal stability of P(AN-CA), evidenced by thermogravimetric analyses in air atmosphere, was found higher than PAN homopolymer and similar to P(AN-IA) copolymers. Therefore, this study successfully demonstrated the great potential of P(AN-CA) copolymers as carbon fiber precursors, taking advantages of the temperature-lowering effects of CA comonomers and higher thermal stability of the CA copolymers for the stabilizing processes.

• Journal of Electrochemical Science and Technology
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• 제8권2호
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• pp.107-114
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• 2017

Pseudo capacitors belong to one group of super capacitors which are consisted with non carbon based electrodes. As such, conducting polymers and metal oxide materials have been employed for pseudo capacitors. Conducting polymer based pseudo capacitors have received a great attention due to their interesting features such as flexibility, low cost and ease of synthesis. Much work has been done using liquid electrolytes for those pseudo capacitors but has undergone various drawbacks. It has now been realized the use of solid polymer electrolytes as an alternative. Among them gel polymer electrolytes (GPEs) are in a key place due to their high ambient temperature conductivities as well as suitable mechanical properties. In this study, composition of a polyacrylonitrile (PAN) based GPE was optimized and it was employed as the electrolyte in a pseudo capacitor having polypyrrole (PPy) electrodes. GPE was prepared using ethylene carbonate (EC), propylene carbonate (PC), sodium thiocyanate (NaSCN) and PAN as starting materials. The maximum room temperature conductivity of the GPE was $1.92{\times}10^{-3}Scm^{-1}$ for the composition 202.5 PAN : 500 EC : 500 PC : 35 NaSCN (by weight). Performance of the pseudo capacitor was investigated using Cyclic Voltammetry technique, Electrochemical Impedance Spectroscopy (EIS) technique and Continuous Charge Discharge (GCD) test. The single electrode specific capacity (Cs) was found out to be 174.31 F/g using Cyclic Voltammetry technique at the scan rate of 10 mV/s and within the potential window -1.2 V to 1.2 V. The same value obtained using EIS was about 84 F/g. The discharge capacity ($C_d$) was 69.8 F/g. The capacity fade over 1000 cycles was rather a low value of 4%. The results proved the suitability of the pseudo capacitor for improving the performance further.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1523-1526
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• 2012

In this work, we prepared activated multi-walled carbon nanotubes/polyacrylonitrile (A-MWCNTs/C) composites by film casting and activation method. Electrochemical properties of the composites were investigated in terms of serving as MWCNTs-based electrode materials for electric double layer capacitors (EDLCs). As a result, the A-MWCNTs/C composites had much higher BET specific surface area, and pore volume, and lower volume ratio of micropores than those of pristine MWCNTs/PAN ones. Furthermore, some functional groups were added on the surface of the A-MWCNTs/C composites. The specific capacitance of the A-MWCNTs/C composites was more than 4.5 times that of the pristine ones at 0.1 V discharging voltage owing to the changes of the structure and surface characteristics of the MWCNTs by activation process.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.305-305
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• 2009

The carbon nano-structured materials could be applied to the fields of advanced fillers, templates, electrode materials, sensor, storage, and absorption materials. The polyacrylonitrile (PAN) based carbon nano-particles provide the remarkable properties of high specific surface area, large pore volume, chemical inertness, and good mechanical stability. In this study, well-defined carbon nano-particles were obtained through pyrolysis of polyacrylonitrile based particles. The precursor nano-particles were prepared by modified aqueous dispersion polymerization using hydrophilic poly(vinyl alcohol) in a water/ N,N-dimethylformamide mixture media. Synthesized precursor nanoparticles have relatively monodisperse particles ranging 80 ~ 250nm. Stable spherical particles are obtained without coagulum or secondary particles in our system. The characteristic of the carbon nanoparticles were investigated in terms of surface area, morphology, and size distribution.

• 한국막학회:학술대회논문집
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• 한국막학회 1997년도 춘계 총회 및 학술발표회
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• pp.34-35
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• 1997

The phase inversion is a significant phenomena in the preparation of membranes and wet spinning. In both these processes, a viscous dope solution is precipitated in a nonsolvent bath and a porous structure is formed under certain conditions. Such structure could have been considered as a diffusion controlled process. The membrane formation of the polymer solution includes both phase separation and gelation. We have studied the influence of variables on the final structure and tried to control the porosity and ultrafiltration(UF) performance of the polyacrylonitrile(PAN) and its copolymer.

• 한국염색가공학회지
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• 제7권2호
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• pp.24-31
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• 1995

The properties of carbon fibers made from PAN are controlled by the heat treatment conditions. The length changes of high strength homo-PAN and co-PAN (acrylonitrile/acrylamide= 98/2wt% ) fibers under constant tensile stress during heat treatment in nitrogen gas were investigated by measuring the shrinkage behavior. In order to elucidate the relation between the length and fine structure change, the measurements of the crystalline orientation and birefringence index etc. were made for the fibers treated under linear heating up to 27$0^{\circ}C$. There are two regions in the length change with heat treatment temperature. The change in the initial period is mainaly due to the relaxation of amorphous molecular chain confined by the fiber-manufacture process. The length change in later period is considered to arise as cyclization reactions. The co-PAN fibers caused a larger shrinkage, while the onset of the shrinkage change in later period is, shifted to lower temperature. Significant morphological changes are shown to precede onset of the cyclization reactions and also during these reactions.

• Composites Research
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• 제26권3호
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• pp.160-164
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• 2013

In this study, the effect of phosphoric acid (PA) as a fiber spinning aid on the strength increase of polyacrylonitrile (PAN) nano-fibers by using modified mechano-electrospinning technologies has been analyzed. The medium carbonization temperature of $800^{\circ}C$ has been selected for the future economic production of these new materials. The concentration of PAN in dimethyl sulfoxide (DMSO) was fixed as 5 wt%. The weight fraction of PA was selected as being 2%, 4%, 6%, and 8% in comparison to PAN. These solutions have been used to make the nanofibers. The mechano-electrospinning apparatus installed in KRICT was made by our own design. By using this apparatus the continous and highly aligned precursor nano-fibers have been obtained. The bundle of 50 well aligned nano diameter continuous fibers with the diametr of 10 microns with 6 wt% phosphoric acid for addition showed maximum mechanical properties of 1.6 GPa as tensile strength and 300 GPa as Young's modulus. The weight of final product can be increased 19%, which can improve the economical benefits for the application of these new materials.