Mechanical and surface properties of HF50S carbon fibers

Gu Hongxing,Zhang Ming,Zhang Shubin,Qi Jingyao 한국탄소학회 2022 Carbon Letters Vol.32 No.3

To thoroughly analyze the mechanical properties and surface conditions of HF50S carbon fibers, the tensile properties, surface morphology, surface chemical element, surface energy, sizing agent properties, and Naval Ordnance Laboratory (NOL) ring of their composites were characterized. Furthermore, the aforementioned properties were exhaustively compared with those of T1000G carbon fibers. The results showed that the tensile strength, modulus, and elongation of the HF50S carbon fibers were 6638 MPa, 297 GPa, and 2.2%, respectively, thus demonstrating that the mechanical properties of the HF50S carbon fibers were on par with those of the T1000G carbon fibers, in addition, the coefficient of variation (Cv) indices of HF50S carbon fiber were below 3%, indicating good stability. The HF50S carbon fibers have a smooth surface without grooves, which is analogous to that of the T1000G carbon fibers prepared by the typical dry jet–wet spinning process. The main component of the sizing agent of the HF50S carbon fibers is an epoxy resin, which is also used for the preparation of epoxy matrix composites. Because the HF50S carbon fiber surface has greater O and N contents than the T1000G carbon fiber surface, the HF50S carbon fibers have more active functional groups and higher surface activity. The surface energy of the HF50S carbon fibers is 30.13 mJ/m2, which is higher than that of the T1000G carbon fibers (28.42 mJ/m2). Owing to the higher strength and surface activity of the HF50S carbon fibers than those of the T1000G carbon fibers, the strength and strength conversion of NOL ring based on the former are slightly higher than those of that prepared using the latter.

Effect of carbonization temperature and chemical pre-treatment on the thermal change and fiber morphology of kenaf-based carbon fibers

Jin-Myung Kim,In-Seong Song,Dong-Hwan Cho,Ik-Pyo Hong 한국탄소학회 2011 Carbon Letters Vol.12 No.3

Kenaf fibers, cellulose-based natural fibers, were used as precursor for preparing kenafbased carbon fibers. The effects of carbonization temperature (700℃ to 1100℃) and chemical pre-treatment (NaOH and NH4Cl) at various concentrations on the thermal change, chemical composition and fiber morphology of kenaf-based carbon fibers were investigated. Remarkable weight loss and longitudinal shrinkage were found to occur during the thermal conversion from kenaf precursor to kenaf-based carbon fiber, depending on the carbonization temperature. It was noted that the alkali pre-treatment of kenaf with NaOH played a role in reducing the weight loss and the longitudinal shrinkage and also in increasing the carbon content of kenaf-based carbon fibers. The number and size of the cells and the fiber diameter were reduced with increasing carbonization temperature. Morphological observations implied that the micrometer-sized cells were combined or fused and then re-organized with the neighboring cells during the carbonization process. By the pre-treatment of kenaf with 10 and 15 wt% NaOH solutions and the subsequent carbonization process, the inner cells completely disappeared through the transverse direction of the kenaf fiber, resulting in the fiber densification. It was noticeable that the alkali pre-treatment of the kenaf fibers prior to carbonization contributed to the forming of kenaf-based carbon fibers.

Carbon fiber coating with MWCNT in the presence of polyethyleneimine of different molecular weights and the effect on the interfacial shear strength of thermoplastic and thermosetting carbon fiber composites

Dongkyu Lee,Youngeun Kim,Oh Hyeong Kwon,Won Ho Park,Donghwan Cho 한국탄소학회 2021 Carbon Letters Vol.31 No.3

The effect of multi-walled carbon nanotubes (MWCNT) coating in the presence of polyethyleneimine (PEI) of different molecular weights (MW) on the interfacial shear strength (IFSS) of carbon fiber/acrylonitrile–butadiene–styrene (ABS) and carbon fiber/epoxy composites was investigated. The IFSS between the carbon fiber and the polymer was evaluated by means of single fiber microbonding test. The results indicated that uses of the carbon fibers uncoated and coated with pristine, low MW PEI-treated, and high MW PEI-treated MWCNT significantly influenced the IFSS of both thermoplastic and thermosetting carbon fiber composites as well as the carbon fiber surface topography. The incorporation of low MW (about 1300) PEI into the carboxylated MWCNT was more effective not only to uniformly coat the carbon fiber with the MWCNT but also to improve the interfacial bonding strength between the carbon fiber and the polymer than that of high MW (about 25,000) PEI. In addition, carbon fiber/epoxy composite exhibited the IFSS much higher than carbon fiber/ABS composite due to the chemical interactions between the epoxy resin and amine groups existing in the PEI-treated MWCNT.

Influence of carbon fibers on interfacial bonding properties of copper-coated carbon fibers

Zhang Guodong,Yang Weizhuang,Ding Jianan,Liu Mengxiang,Di Chengrui,Ci Shengzong,Qiao Kun 한국탄소학회 2024 Carbon Letters Vol.34 No.3

Copper-coated carbon fibers have excellent conductivity and mechanical properties, making them a promising new light-weight functional material. One of the main challenges to their development is the poor affinity between carbon fiber and metals. This paper selects different carbon fibers for copper electroplating experiments to study the effect of carbon fiber properties on the interface bonding performance between the copper plating layer and carbon fibers. It has been found that the interfacial bonding performance between copper and carbon fiber is related to the degree of graphitization of carbon fiber. The lower the degree of graphitization of carbon fiber, the smaller the proportion of carbon atoms with sp2 hybrid structure in carbon fiber, the stronger the interfacial bonding ability between carbon fiber and copper coating. Therefore, carbon fiber with lower graphitization degree is conducive to reducing the falling off rate of copper coating and improving the quality of copper coating, and the conductivity of copper-plated carbon fibers increases with the decrease of graphitization degree of carbon fibers. The conductivity of copper-plated carbon fibers increases by more than six times when the graphitization degree of carbon fibers decreases by 23.9%. This work provides some benchmark importance for the preparation of high-quality copper-plated carbon fibers.

금속(Ag, Cu, Co)함유 활성탄소섬유의 미세공도와 금속입자의 거동

임광순,엄상용,유승곤,Edie, Dan D. 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.4

개질된 석유 피치에 금속(Ag, Cu, Co)염들을 혼합하여 전구체 피치를 만들고 용융방사하여 금속함유 탄소섬유를 만든 후, 이를 수증기로 활성화하여 활성탄소섬유를 만들고 미세공도와 금속 입자의 거동을 관찰하였다. 전구체 피치의 용융방사온도는 금속함량이 증가함에 따라 선형적으로 증가했다. Co와 Cu가 함유된 탄소섬유는 공기분위기에서 400℃에서부터, Ag이 함유된 탄소섬유는 금속이 함유되지 않은 탄소섬유와 같이 480℃에서부터 급격히 분해되었다. 금속을 함유하지 않은 활성탄소섬유의 평균 기공과 비표면적은 20 Å, 1,100㎡/g이었다. 금속함유 활성탄소섬유는 금속의 촉매적 가속 때문에 활성화 속도가 크고 평균기공직경과 중기공 비율은 커졌으나, 비표면적은 감소하였다. 금속 함유 활성탄소섬유는 1 wt%가 함유되어도 각각의 금속에 대응하는 피크가 나타났다. 활성탄소섬유내에서 은 입자들은 비교적 균일하게 분포되었으나, 구리와 코발트 입자들은 일부가 합체하여 큰 입자를 형성하는 경향을 보였으며, 합체된 구리입자들은 수증기 활성화동안 일부가 섬유로부터 빠져나와 표면에 거대 기공을 남겼다. Metal (Ag, Cu, Co)salts were mixed to reformed petroleum pitches for production of metal-containing carbon fibers. The carbon fiber was steam activated to investigate the microporosity and the behaviour of metal particles in activated carbon fiber. The melt spinning temperature of precursor pitch linearly increased as the metal content increased. Cobalt and copper-containing carbon fibers were decomposed after 400℃, silver-containing and non-metal containing carbon fibers were decomposed after 480℃ in air. The average pore diameter and specific surface area of non-metal containing activated carbon fibers were 20 Å and 1,100 ㎡/g. The activation rates of metal-containing carbon fibers increased by catalytic acceleration of metals. Average pore diameter and mesopore fraction of metal-containing activated carbon fiber increased as the metal content increased, however, specific surface area decreased. The metal-containing activated carbon fibers showed peaks corresponding to their own metal. Silver particles were uniformly distributed in activated carbon fibers, while copper and cobalt particles tended to coalesence and some of coalesced copper exited from activated carbon fibers resulting in macropores on the surface of activated carbon fibers during the steam activation.

Thermal Conductivity and Thermal Expansion Behavior of Pseudo-Unidirectional and 2-Directional Quasi-Carbon Fiber/Phenolic Composites

Cho, Donghwan,Choi, Yusong,Park, Jong Kyoo,Lee, Jinyong,Yoon, Byung Il,Lim, Yun Soo The Korean Fiber Society 2004 Fibers and polymers Vol.5 No.1

In the present paper, a variety of fiber reinforcements, for instance, stabilized OXI-PAN fibers, quasi-carbon fibers, commercial carbon fibers, and their woven fabric forms, have been utilized to fabricate pseudo-unidirectional (pseudo-UD) and 2-directional (2D) phenolic matrix composites using a compression molding method. Prior to fabricating quasi-carbon fiber/phenolic (QC/P) composites, stabilized OXI-PAN fibers and fabrics were heat-treated under low temperature carbonization processes to prepare quasi-carbon fibers and fabrics. The thermal conductivity and thermal expansion/contraction behavior of QC/P composites have been investigated and compared with those of carbon fiber/phenolic (C/P) and stabilized fiber/phenolic composites. Also, the chemical compositions of the fibers used have been characterized. The results suggest that use of proper quasi-carbonization process may control effectively not only the chemical compositions of resulting quasi-carbon fibers but also the thermal conductivity and thermal expansion behavior of quasi-carbon fibers/phenolic composites in the intermediate range between stabilized PAN fiber- and carbon fiber-reinforced phenolic composites.

Study of a melt processable polymer precursor for carbon fiber

Samsuddin F. Mahmood,Benjamin L. Batchelor,Minhye Jung,Kyusoon Park,Walter E. Voit,Bruce M. Novak,Duck Yang 한국탄소학회 2019 Carbon Letters Vol.29 No.6

Carbon fibers (CF) are predominantly being manufactured from polyacrylonitrile (PAN) based precursors which require solution spinning utilizing health hazardous organic solvent. This also adds to the cost of production due to the investment for the solvent recovery. Study of melt processable precursors has long been sought as a solution for health and environmental problems associated with the use of hazardous solvent. No use of solvent for spinning will also reduce the cost of manufacturing. Our coworker Deng et al. reported the possibility of using acrylonitrile-co-1-vinylimidazole (AN/VIM) copolymer as melt processable CF precursor. Here we report a successful preparation of carbon fiber from the co-polymer. We successfully demonstrated the preparation of thinner precursor fibers and carbon fibers through our optimization study of melt spinning, annealing, stabilization and carbonization.

유리섬유 코팅사와 탄소섬유를 이용한 일방향 탄소섬유시트 제조 공정이 콘크리트 보강에 미치는 영향

권지은,권선민,채시현,정예담,김종원 한국염색가공학회 2022 韓國染色加工學會誌 Vol.34 No.3

In this study, carbon fiber and coated glass fiber are applied to warp and weft fiber in order to reduce the amount of carbon fiber used in carbon fiber fabrics, which are often used for reinforcement of building structures. A low-cost thermoplastic resin was coated on glass fibers to prepare a shape-stabilizing glass fiber. A unidirectional carbon fiber sheet was manufactured using the prepared coated glass fiber and carbon fiber. In order to identify whether it can be used for reinforcing architectural and civil structures, it was attached to a concrete specimen and its mechanical properties were analyzed. The optimum manufacturing conditions for the coated glass fiber were 0.3 mm in diameter of the coating nozzle, the coating temperature was 190 ℃, and the coating speed was 0.3 m/s. 14 mm was optimal for the weft spacing of the coated glass fiber. The flexural strength of the concrete reinforced with the manufactured unidirectional carbon fiber sheet was slightly lower than that of the concrete reinforced with carbon fiber fabric, but it was confirmed that the reinforcement effect was better when the amount of carbon fiber was considered.

PHYSICOMECHANICAL CHARACTERISTICS OF CARBON FIBER REINFORCED POLYMER COMPOSITE USING X-RAY DIFFRACTION, ATOMIC FORCE AND ELECTRON MICROSCOPIES

Ye Htet Lin,Preechar Karin,Patcharee Larpsuriyakul,Naoto Ohtake 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.5

The physicomechanical characteristics of PAN-based carbon fibers were investigated by SEM-EDS, XRD, TEM and AFM analysis while the mechanical properties of the composites were studied by tensile, flexural and Charpy impact tests with ASTM standards. Regarding the tensile test of carbon fiber fabric, the average tensile strength of CF-Ⅰ, CF-II and CF-III fibers were around 147 MPa, 137 MPa and 225 MPa and the tensile modulus of those were 12.8 GPa, 13.2 GPa and 12.8 GPa, respectively. Later, the nanostructure of carbon fiber was recognized not as a pure graphite carbon structure because they mixed with graphite and amorphous structures. The higher tensile strength and modulus of CF-III fiber fabric was lower interlayer spacing (d002) because it consisted of more graphene layers in the graphite structure when compared with CF-Ⅰ and CF-Ⅱ fiber fabrics. Concerning AFM analysis’s results, CF-Ⅰ fiber fabric has higher surface roughness (Ra) of 34.8 nm and more in-depth with wider pit lines along the fiber axis, which caused higher mechanical properties among the three composites. According to this article, the nanostructure of carbon fibers had a lower impact on CFRP composite because the interfacial bonding between fiber and epoxy matrix, which obtained the higher mechanical properties in the composite, was directly enhanced by the higher surface roughness of the fibers.

탄소섬유강화플라스틱 유래 폐 탄소섬유로 제조된 불화탄소 기반 리튬일차전지의 전기화학적 특성

하나은 ( Naeun Ha ),임채훈 ( Chaehun Lim ),하성민 ( Seongmin Ha ),명성재 ( Seongjae Myeong ),이영석 ( Young-seak Lee ) 한국공업화학회 2023 공업화학 Vol.34 No.5

본 연구에서는 탄소섬유강화플라스틱(CFRP)을 열분해하여 얻은 폐 탄소섬유를 이용하여 기상 불소화를 통해 불화탄소를 제조하고 리튬일차전지의 환원극 소재로 재활용하고자 하였다. 먼저 열분해로 얻은 폐 탄소섬유의 물리화학적 특성을 파악하였으며, 이 폐 탄소섬유에 기상 불소화 효과를 평가하기 위하여 불화탄소의 구조적, 화학적 특성을 분석하였다. XRD 분석에 의해 폐 탄소섬유의 육각망탄소 적층구조(002피크)는 기상 불소화의 온도가 증가함에 따라 점차 불화탄소 구조(001피크)로 전환되었음을 확인하였다. 이 불화탄소를 이용하여 제조된 리튬일차전지의 방전용량은 최대 862 mAh/g이었다. 이는 다른 탄소 재료로 제조한 불화탄소 기반 리튬이온차전지의 방전용량과 비교하였을 때 우수한 성능을 보였다. 이러한 결과는 폐 CFRP 기반 폐탄소섬유를 이용한 불화탄소는 리튬일차전지의 환원극 소재로 활용할 수 있을 것으로 여겨진다. In this study, waste carbon fiber obtained by pyrolysis of carbon fiber reinforced plastic (CFRP) was used to produce carbon fluoride through vapor phase fluorination and recycled as a reducing electrode material for lithium primary batteries. First, the physicochemical properties of the waste carbon fiber obtained by pyrolysis were determined, and the structural and chemical properties of carbon fluoride were analyzed to evaluate the effect of vapor phase fluorination on the waste carbon fiber. XRD analysis confirmed that the hexagonal network carbon laminated structure (002 peak) of the waste carbon fiber was gradually converted into a carbon fluoride structure (CF_X, 001 peak) as the temperature of gas phase fluorination increased. The discharge capacity of the lithium primary battery produced using this carbon fluoride was up to 862 mAh/g. This was compared to the discharge capacity of carbon fluoride-based Li-ion batteries made of other carbon materials. These results suggest that carbon fluoride made from waste CFRP-based carbon fibers can be used as a reducing electrode material for Li-ion batteries.