• Carbon letters
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• 제7권3호
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• pp.161-165
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• 2006

Activated carbon fiber could be prepared at 973 K by catalytic activation using potassium hydroxide. Phenol resin fiber (Kynol) was impregnated with potassium hydroxide ethanol solution, carbonized and activated at 973 K, resulting in activated carbon fibers with different porosities. The potassium hydroxide accelerated the activation of the fiber catalytically to form narrow micropore preferentially in carbon dioxide atmosphere. The narrow micropore volume of 0.3~0.4 cc/g, total pore volume of 0.3~0.8 cc/g, mean pore width of 0.5~0.7 nm was obtained in the range of 20~50% burnoff.

• 한국결정성장학회지
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• 제25권6호
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• pp.290-293
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• 2015

최근 사회기반시설물의 구조물 유지관리 분야의 관심이 높아짐에 따라 새로운 유지관리 공법 및 신소재에 관한 연구가 활발히 진행되어지고 있다. 그중에서도 유지관리의 주요 대상인 교량 유지관리에는 탄소섬유를 이용한 공법이 주목을 받고 있다. 탄소섬유시트(Carbon Fiber Sheet, 이하 CFS)는 이미 여러 연구자들이 국내에서도 재료시험 및 보강공법에 관한 연구를 진행하여 연구결과가 보고되고 있지만, 탄소섬유 스트랜드 시트(Carbon Fiber Strand Sheet, 이하 CFSS)는 최근 새롭게 개발된 재료로써 아직까지 국내에는 연구 성과가 없는 실정이다. 따라서, 본 연구에서는 CFSS를 RC 상판 공시체에 접착보강하여 내피로성을 평가하였다. 그 결과, 무보강 RC 상판 공시체에 비해 약 25.3배의 보강 효과가 확인되었고, CFS 접착보강 RC 상판 공시체에 비교하여 약 1.2배의 보강 효과가 확인되었다.

• 센서학회지
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• 제17권3호
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• pp.162-167
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• 2008

In this paper we report on the electrical properties of carbon fiber which is an attractive material for strain gauges and can also be applied to resonating micro sensors. The carbon fibers used in this research was manufactured from polyactylonitrile (PAN). The fabricated carbon fibers had about $10\;{\mu}m$ in length and several centimeters in length. We employed a micro structure to measure electrical properties of the carbon fiber. The measured electrical resistivity of the carbon fibers were about $3{\times}10^{-3}{\Omega}{\cdot}cm$ A gauge factor of the carbon fiber is also observed with the same system and it was about 400, depending on the structure of the carbon fiber. For the sensor applications of the carbon fiber, it is selectively placed between the gap of Al electrodes using a dielectrophoresis method. When the carbon fiber is resonated by a piezoelectric ceramic, resistance change at a variety of resonance mode was observed through an electrical system.

• Carbon letters
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• 제15권3호
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• pp.162-170
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• 2014

Pitch is an attractive raw material for carbon fiber precursors due to its low cost stemming from its availability as a residue of coking and petroleum processes. Ford Motor Company reported a carbon fiber target price of $11.0/kg by using a fast cycle-time manufacturing method with carbon fiber in an inexpensive format, allowing for an average retail price of gasoline of $3.58/gallon. They also recommended the use of carbon fiber with strength of 1700 MPa, modulus of 170 GPa, and 1.5% elongation. This study introduced a ca. $5.5{\mu}m$ carbon fiber with 2000 MPa tensile strength obtained from a precursor through simple distillation of petroleum residue. Petroleum pitch based carbon nanofibers prepared via electrospinning were characterized and potential applications were introduced on the basis of their large specific surface area and relatively high electrical conductivity.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.743-749
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• 1999

Recently new rehabilitation techniques have been proposed with advanced composite materials like carbon fiber, aramid, glass fiber sheet and so forth. The purpose of this paper is to investigate the mechanical characteristics of reinforced concrete columns confined with carbon fiber sheet and evaluate the degree of their strengthening effect. For the test, the specimen size of column is 15cm$\times$15cm$\times$90cm reinforced with 4 number of main bars of 10 mm diameter, tied bars of 6 mm diameter and slenderness ratio 20. Columns were wrapped with carbon fiber sheet along the column length. It is necessary to make some assumption regarding the confinement of carbon fiber sheet to apply to reinforced concrete columns under concentric loads. The strength gain effect of columns confined with carbon fiber sheet could be predicted using the proposed equation.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1993년도 ACT 93
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• pp.622-626
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• 1993

• 한국세라믹학회지
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• 제35권6호
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• pp.603-609
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• 1998

The composites of insulating polymer filled with conducting carbon-fiber were fabricated by molding press method. To understand the fiber aspect-ratio dependence of electrical conductivity the aspect ratio was varied from 4 to 10 The percolation thresholds of transition from the insulator to the conductor de-creased as the fiber aspect ratio increased. The percolation threshold of fiber-segregated composite in this study was smaller than that of fiber-random composite shown in other study. When the electrical con-ductivity curves were fitted by general effective medium equation morphological variable(t) decreased as the fiber aspect-ratio increased.

• Carbon letters
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• 제10권1호
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• pp.43-51
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• 2009

Carbon fibers are a new breed of high-strength materials. The existence of carbon fiber came into being in 1879 when Edison took out a patent for the manufacture of carbon filaments suitable for use in electric lamps. However, it was in the early 1960s when successful commercial production was started, as the requirements of the aerospace industry for better and lightweight materials became of paramount importance. In recent decades, carbon fibers have found wide applications in commercial and civilian aircraft, along with recreational, industrial, and transportation markets as the price of carbon fiber has come down and technologies have matured. The market for carbon fiber has experienced a good growth in recent years. The growth rate for the last 23years was about 12%. The article reviewed 9,641 Korea, U.S., Japan, Europe patents issued in the carbon fibers in order to offer additional insight for researchers and companies seeking to navigate carbon fiber patent landscape. This article will provide you with all the valuable information and tools you will need to investigate your study successfully within the carbon fiber field. This article also will save you hundreds of hours of your own personal research time and will significantly benefit you in expanding your business in the carbon fiber market.

• Carbon letters
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• 제9권4호
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• pp.316-323
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• 2008

The factors that influence ablation resistance in fiber composites are properties of the reinforced fiber and matrix, plugging quantity of fiber, geometrical arrangement, crack, pore size, and their distributions. To examine ablation resistance according to distribution of crack and pore size that exist in carbon/carbon composites, this study produced various sizes of unit cells of preforms. They were densified using high pressure impregnation and carbonization process. Reinforced fiber is PAN based carbon fiber and composites were heat-treated up to $2800^{\circ}C$. The finally acquired density of carbon/carbon composites reached more than $1.932\;g/cm^3$. The ablation test was performed by a solid propellant rocket engine. The erosion rate of samples is below 0.0286 mm/s. In conclusion, in terms of ablation properties, the higher degree of graphitization is, the more fibers that are arranged vertically to the direction of combustion flame are, and the less interface between reinforced fiber bundle and matrix is, the better ablation resistance is shown.

• 한국해양공학회지
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• 제11권2호
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• pp.48-56
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• 1997

This work has been investigated in order to study the influence of the moisture absorption on the mechanical pf the glass fiber/epoxy resein composites and the carbon fiber/epoxy resein composites. The types of glass fiber used in the glass fiber/epoxy resein composites were randomly oriented fiber and plain fabric fiber. And carbon fiber.epoxy resein composites was laminated with fabric prepreg which was formed with carbon fiber and epoxy resein. Both composites were immersed up to 100 days in distilled water at $80^{\circ}C$, and then dried up to 3 days in an oven at 80$80^{\circ}C$. Both composites were measured for the weight gain of water(wt.%) and tensile strength through immersion and dry time. Consequently, it was found that the tensile strength of thw glass fiber/epoxy resein composites and the carbon fiber/epoxy resein composites were reduced proportionally to the moisture absortion rate. Also, the tensile strength of glass fiber composites was decreased more than that of the carbon fiber composites. Additionally, it was found that the tensile strength of all composites which decreased by moisture absorption were partly recovered by drying in an oven at 80$80^{\circ}C$.