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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
Korean Carbon Society
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Volume & Issues
Volume 5, Issue 4 - Dec 2004
Volume 5, Issue 3 - Sep 2004
Volume 5, Issue 2 - Jun 2004
Volume 5, Issue 1 - Mar 2004
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Effects of Fiber Surface-Treatment and Sizing on the Dynamic Mechanical and Interfacial Properties of Carbon/Nylon 6 Composites
Cho, Dong-Hwan ; Yun, Suk-Hyang ; Kim, Jun-Kyung ; Lim, Soon-Ho ; Park, Min ; Lee, Geon-Woong ; Lee, Sang-Soo ;
Carbon letters, volume 5, issue 1, 2004, Pages 1~5
The effects of fiber surface-treatment and sizing on the dynamic mechanical properties of unidirectional and 2-directional carbon fiber/nylon 6 composites by means of dynamic mechanical analysis have been investigated in the present study. The interlaminar shear strengths of 2-directional carbon/nylon 6 composites sized with various thermosetting and thermoplastic resins are also measured using a short-beam shear test method. The result suggests that different surface-treatment levels onto carbon fibers may influence the storage modulus and tan
behavior of carbon/nylon 6 composites, reflecting somewhat change of the stiffness and the interfacial adhesion of the composites. Dynamic mechanical analysis and short-beam shear test results indicate that appropriate use of a sizing material upon carbon fiber composite processing may contribute to enhancing the interfacial and/or interlaminar properties of woven carbon fabric/nylon 6 composites, depending on their resin characteristics and processing temperature.
Controlling the Hardness and Tribological Behaviour of Non-asbestos Brake Lining Materials for Automobiles
Mathur, R.B. ; Thiyagarajan, P. ; Dhami, T.L. ;
Carbon letters, volume 5, issue 1, 2004, Pages 6~11
In spite of unparalleled combination of essential material properties for brake linings and clutch facings, replacement for asbestos is seriously called for since it is a health hazard. Once asbestos is replaced with other material then composition and properties of brake pad changes. In certain cases hardness of the material may be high enough to affect the rotor material. In this study, hardness of the brake pad has been controlled using suitable reinforcement materials like glass, carbon and Kevlar pulp. Brake pad formulations were made using CNSL (cashew net shell liquid) modified phenolic resin as a binder, graphite or cashew dust as a friction modifier and barium sulphate, talc and wollastonite as fillers. Influence of each component on the hardness value has been studied and a proper formulation has been arrived at to obtain hardness values around 35 on Scleroscopic scale. Friction and wear properties of the respective brake pad materials have been measured on a dynamometer and their performance was evaluated.
Influence of Oxyfluorination on Properties of Polyacrylonitrile (PAN)- Based Carbon Fibers
Lim, In-Seub ; Yoo, Seung-Hwa ; Park, Il-Nam ; Lee, Young-Seak ;
Carbon letters, volume 5, issue 1, 2004, Pages 12~17
In this study, the oxyfluorination of PAN-based carbon fibers was undertaken at room temperature using fluorine-oxygen mixtures, and the influence of oxyfluorination on properties was investigated. The surface characteristics of the modified fiber were determined by using X-ray photoelectron spectroscopy (XPS) and dynamic contact angle analyzer. The oxyfluorination of carbon fibers was one of the more effective methods to increase surface wettability by the formation of semicovalent C-F bond and C-O bond depending on reaction conditions. When oxygen mole fraction is increased from 0.5 to 0.9, it is probable that attached fluorine atoms at the surface of the fibers reacted with other components. As increased oxyfluorination time and decreased its pressures, semi-covalent peak is increased at 0.5 of oxygen mole fraction. The total surface free energy of oxyfluorinated carbon fibers decreased with increasing oxygen mole fraction over 0.5. These results indicate that the surface of carbon fibers became much more hydrophilic after the short oxyfluorination. The surface free energy of oxyfluorinated carbon fibers progressively decreased after 10 min treatment. The polar components of surface free energies were however, significantly higher for all oxyfluorinated samples than that for the untreated carbon fiber.
Monitoring Failure Behaviour of Pultruded CFRP Composites by Electrical Resistance Measurement
Mao, Yaqin ; Yu, Yunhua ; Wu, Dezhen ; Yang, Xiaoping ;
Carbon letters, volume 5, issue 1, 2004, Pages 18~22
The failure behaviours of unidirectional pultruded carbon fiber reinforced polymer (CFRP) composites were monitored by the electrical resistance measurement during tensile loading, three-point-bending, interlaminar shear loading. The tensile failure behaviour of carbon fiber tows was also investigated by the electrical resistance measurement. Infrared thermography non-destructive evaluation was performed in real time during tensile test of CFRP composites to validate the change of microdamage in the materials. Experiment results demonstrated that the CFRP composites and carbon fiber tows were damaged by different damage mechinsms during tensile loading, for the CFRP composites, mainly being in the forms of matrix damage and the debonding between matrix and fibers, while for the carbon fiber tows, mainly being in the forms of fiber fracture. The correlation between the infrared thermographs and the change in the electrical resistance could be regarded as an evidence of the damage mechanisms of the CFRP composites. During three-point-bending loading, the main damage forms were the simultaneity fracture of matrix and fibers firstly, then matrix cracking and the debonding between matrix and fiber were carried out. This results can be shown in Fig. 9(a) and (b). During interlaminar shear loading, the change in the electrical resistance was related to the damage degree of interlaminar structure. Electrical resistance measurement was more sensitive to the damage behaviour of the CFRP composites than the stress/time curve.
A Study of Partial Carbonisation for the Development of Pitch Based Carbon Fibres
Aggarwal, R.K. ; Bhatia, G. ; Raman, V. ; Saha, M. ; Mishra, A. ;
Carbon letters, volume 5, issue 1, 2004, Pages 23~26
A study of partial carbonisation of green pitch fibres to temperatures in the range of 500-
was carried out on three precursors - a neat pitch and two polymer modified pitches, with a view to find out a suitable temperature at which the fibres acquire considerably improved toughness or handleability (compared to that in the green stage) for their subsequent processing into carbon fibres. A partial carbonisation temperature of 500-
has been identified to result in a remarkable improvement in the toughness/handleability of the fibres in all the three cases. However, from techno-economical considerations, the neat pitch appears to provide the best precursor system for the production of pitch based carbon fibres.
A Structural Study of the Oxidized High Modulus Pitch Based Carbon Fibers by Oxidation in Carbon Dioxide
Roh, Jae-Seung ;
Carbon letters, volume 5, issue 1, 2004, Pages 27~33
Structural changes of high modulus carbon fiber by oxidation in carbon dioxide gas using SEM, TEM, and XRD have been observed. It was shown that the originally high modulus carbon fiber is composed of highly ordered graphitic crystalline area and non-crystalline area. It was observed that the La increases during the whole oxidation process. It was shown that the oxidation of high modulus carbon fiber initiates at the non-crystalline area and at the ends of fiber. The large pores developed in fiber by direction of fiber length at high temperature (
), and the small pores developed on the fiber surface at low temperature (
). In conclusion, it is found that the oxidation of the carbon fiber was progressed through the imperfection.