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.

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.

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.

분체공학,유동층,고분자,재료(무기, 유기) : 금속(Ag, Cu, Co)함유 활성탄소섬유의 미세공도와 금속입자의 거동

임광순 ( Im Gwang Sun ),엄상용 ( Eom Sang Yong ),유승곤 ( Yu Seung Gon ),( Dan D. Edie ) 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.4

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.

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.

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.

Carbon fibers/nickel nanocomposite particles reinforced ethylene vinyl acetate stretchable conductive polymer: fabrication, microstructure, electrical and mechanical properties

Daoush Walid M.,Al-Zuair Abdullah Fahad,Saharudin Mohd Shahneel,Inam Fawad 한국탄소학회 2024 Carbon Letters Vol.34 No.5

Carbon fibers of polyacrylonitrile (PAN) type were coated with nickel nanoparticles using a chemical reduction method in alkaline hydrazine bath. The carbon fibers were firstly heated at 400 °C and then chemically treated in hydrochloric acid followed by nitric acid to clean, remove any foreign particles and functionalized its graphitic surfaces by introducing some functional groups. The functionalized carbon fibers were coated with nickel to produce 10 wt% Cf/Ni nanocomposites. The uncoated heat treated and the nickel coated carbon fibers were investigated by SEM, EDS, FTIR and XRD to characterize the particle size, morphology, chemical composition and the crystal structure of the investigated materials. The nickel nanoparticles were successfully deposited as homogeneous layer on the surface of the functionalized carbon fibers. Also, the deposited nickel nanoparticles have quazi-spherical shape and 128–225 nm median particle size. The untreated and the heat treated as well as the 10 wt% Cf/Ni nanocomposite particles were further reinforced in ethylene vinyl acetate (EVA) polymer separately by melt blending technique to prepare 0.5 wt% Cf-EVA polymer matrix stretchable conductive composites. The microstructures of the prepared polymer composites were investigated using optical microscope. The carbon fibers as well as the nickel coated one were homogenously distributed in the polymer matrix. The obtained samples were analyzed by TGA. The addition of the nickel coated carbon fibers to the EVA was improved the thermal stability by increasing the thermal decomposition temperature Tmax1 and Tmax2. The electrical and the mechanical properties of the obtained 10 wt% Cf/Ni nanocomposites as well as the 0.5 wt% Cf-EVA stretchable conductive composites were evaluated by measuring its thermal stability by thermogravimetric analysis (TGA), electrical resistivity by four probe method and tensile properties. The electrical resistivity of the fibers was decreased by coating with nickel and the 10 wt% Cf/Ni nanocomposites has lower resistivity than the carbon fibers itself. Also, the electrical resistivity of the neat EVA is decreased from 3.2 × 1010 to 1.4 × 104 Ω cm in case of the reinforced 0.5 wt% Cf/Ni-EVA polymer composite. However, the ultimate elongation and the Young’s modulus of the neat EVA polymer was increased by reinforcing with carbon fibers and its nickel composite.