Masatoshi Shioya; Takashi Kajikawa; Kuniaki Takahashi; Yoshiki Sugimoto
Abstract
Development of carbon fibers from alternative precursory materials through new production processes is a recent topic of active research. In such a research, the maximum available tensile strength, i. e. the tensile strength which will be achieved after elaboration to suppress defect formation during ...
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Development of carbon fibers from alternative precursory materials through new production processes is a recent topic of active research. In such a research, the maximum available tensile strength, i. e. the tensile strength which will be achieved after elaboration to suppress defect formation during production process, is the matter of great concern. We have developed a method for determining this strength through the tensile test on a single fiber after introducing an artificial notch. In the present paper, this method has been refined. By using the refined method, the distribution of the maximum available tensile strength at various radial positions has been measured for a polyacrylonitrile-based carbon fiber. The difference between the maximum available tensile strength and the strength predicted using other methods such as those based on the fracture toughness and the fiber-length dependence of the tensile strength has also been discussed.
Rakesh Kumar; Seema Joon; Avanish P. Singh; Brij P. Singh; S. K. Dhawan
Abstract
In response to the striking research activity and publications in fabrication of multifunctional materials, the present work is an attempt to fabricate processible composite sheets of poly (o-anisidine)-carbon fiber (PoACF) by a facile, low cost method and find their use in electromagnetic interference ...
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In response to the striking research activity and publications in fabrication of multifunctional materials, the present work is an attempt to fabricate processible composite sheets of poly (o-anisidine)-carbon fiber (PoACF) by a facile, low cost method and find their use in electromagnetic interference (EMI) shielding in X-band (8.2-12.4 GHz). PoACF composite is synthesized by in-Situ oxidative emulsion polymerization and transformed into thin sheets by compression molding technique using different ratio of phenolic novolac resin as a binder. The prepared PoACF composites and sheets are characterized by SEM, TGA, UV-vis, & FT-IR techniques. PoACF sheets have conductivity of the order of 10 -3 to 10 -1 S/cm and maximum shielding effectiveness of 32.57 dB at 4 mm thickness. These sheets have flexural strength between 18.82 to 41.28 MPa. The sheets of PoACF composite have sufficient thermal as well as mechanical stability and may be accepted as an economical material for EMI shielding application.
Abstract
The preparation process of carbon fiber sulphoaluminate cement composite (CFSC) was intimately associated with its piezoresistivity effect. In this paper the piezoresistivity effects of CFSC prepared by different preparation processes were investigated. The experimental results indicated there was no ...
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The preparation process of carbon fiber sulphoaluminate cement composite (CFSC) was intimately associated with its piezoresistivity effect. In this paper the piezoresistivity effects of CFSC prepared by different preparation processes were investigated. The experimental results indicated there was no significance difference of the variation amplitude for all specimens. Meanwhile, the good reversibility order of the piezoresistivity effect for all specimens was the specimen prepared by pressing, the specimen prepared by extrusion and the specimen prepared by casting. This phenomenon was related to the interfacial layer structure. Therefore, pressing and extrusion technology could improve the reversibility of the piezoresistivity effect of CFSC. Copyright © 2011 VBRI press.
Wang Shoude; Lu Lingchao; Cheng Xin
Abstract
Small size particle of ultra-fine fly ash was contributed to the dispersion of carbon fiber in composite in the preparation process. The dispersibility of carbon fiber in composite was associated with self-sensing property of composite. The effect of ultra-fine fly ash on the change in relative dielectric ...
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Small size particle of ultra-fine fly ash was contributed to the dispersion of carbon fiber in composite in the preparation process. The dispersibility of carbon fiber in composite was associated with self-sensing property of composite. The effect of ultra-fine fly ash on the change in relative dielectric constant of carbon fiber sulphoaluminate cement composite under stress was investigated. The sensitivity, accuracy and reversibility of the change in relative dielectric constant under stress have been improved when 10% content (by mass of cement) of ultra-fine fly ash was added into carbon fiber sulphoaluminate cement composite (CFSC). Besides promoting micro capacitor creation, ultra-fine fly ash could endow CFSC with excellent mechanical property and weaken the ions polarization effect. The combination of above three effects upgraded the dielectric behavior of CFSC under stress.
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