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255. Fracture behavior of mesophase carbon fiber
Abstracts
233
252. Influence of processing variables on carbon fiber properties in a continuous process system T. Nagabhushanan, Th. Miiller, A. E. Simionato and J. L. Comes da Silva (Centro T&nico
256. Morphological rearrangements in conversion of acrylic fibers to carbon fibers. Oxidative stabilization M. K. Jain, P. Desai and A. S. Abhiraman (Geor-
Aeroespacial-IPD-PMR, 12.200~Scio Jo& dos Campos, ScZoPaulo, Brasil). Young’s modulus and tensile
gia Institute of Technology, School of Textile Engineering, Georgia Tech, Atlanta, GA 30332, U.S.A.).
strength of carbon fibres depend strongly on the preferred orientation of carbon layers in the fibres. The preferred orientation of these graphite layers can be increased by stretching the fibres during all stages of C-fibre production. In this paper the influence of the degree of prestretching and oxidation process parameters on intermediate products and on the properties of resulting C-fibres from PAN are presented.
Changes in orientational and lateral order and in mechanical properties occurring at different stages in the conversion of an acrylic polymer to carbon fibers are characterized. The results obtained so far indicate that significant morphological rearrangements precede the onset of reactions during oxidative stabilization. Based on the experimental results, a suitable morphological model for the precursor fibers has been identified. Results from experiments to produce precursor fibers with significantly higher order by deformation under conditions of “internal mobility” at high temperatures will also be presented.
253. Transverse properties of carbon and kevlar fibre composites J. F. Helmer and R. J. Diefendorf (Materials Engineering Department, Rensselaer Polytechnic Institute, Troy, NY 12181, U.S.A.). The prediction of
transverse laminae properties from those of constituents is an important aspect of better understanding overall composite behavior. Axial properties of fibres alone and in composites are both predictable from theory and are easily measured. The transverse properties, particularly of anisotropic fibres are almost impossible to generally predict and difficulties arise in direct experimental measurements off the fibre. Laminates of various filament volume ratios were constructed and measured for transverse CTE and transverse modulus so as to extrapolate a value for the fibre. 254. Structure and microtexture of some pitch-base fibres M. Guigon and A. Oberlin (Laboratoire Marcel Mathieu, ER 131 du CNRS, UER Sciences, 45046-Orleans Cedex, France). The three pitch-base
fibres studied more or less (graphitized) have lamellar radial texture, where defectives zones are distributed almost periodically, in bands parallel to the fibre axis (sometimes transversely). Defective zones are crumpled partially graphitized areas and turbostratic porous ones. The lamellar texture favors high Young’s modulus and low tensile strength, whereas defective zones do the reverse effect.
257. Stabilization of poly(acrylonitrile) copolymer precursor in air at 265% G. L. Collins, N. W. Thomas and G. E. Williams (Celanese Research Company, 86 Morris Avenue, Summit, NJ 07901, U.S.A.). An empirical kinetic
description of poly(acrylonitrile) copolymer stabilization has been developed which is based on the heat evolution from PAN materials during an isothermal treatment at 265°C. This approach avoids the difficulties encountered in attempting to extract kinetic information from scanning temperature methods such as DSC. The kinetic model developed has been useful in predicting the thermal behavior of partially stabilized copolymer fibers. 258. Carbon filaments on separated iron clusters J. Galuszkat and M. H. Back (Ottawa-Carleton Institute for Research and Graduate Studies in Chemistry, University of Ottawa Campus, Ottawa, Canada KIN 984). A new approach to the preparation of
metal surfaces for the catalytic formation of filamentous carbon is described. The procedure has allowed the production and observation (by SEM) of single, isolated carbon filaments. The filaments have been subjected to oxidation and to treatment with acid solution, which clearly identified the position of the metal cluster within the filament and the direction of growth of the filament.
255. Fracture behavior of mesophase carbon fiber C. B. Ng, G. W. Henderson, M. Buechler and J. L. White (Materials Sciences Laboratory, The Aerospace
TPresent address: Energy Research Laboratories, CANMET, Ottawa Canada, KlA OGI.
Corporation, P.O. Box 92957, Los Angeles, CA 90009, U.S.A.). Three structural models based on
259. Formation of vapor-grown carbon fibers by seed ing method of metal ultra-fine particles Morinobu Endo (Faculty of Engineering, Shinshu University, Wakasato, Nagano, 380, Japan). Kunio Komaki (Ohmachi Research Laboratory, Showa Denko Co., Ltd., Ohmachi, 398, Japan). Vapor-grown carbon fibers have been successfully grown by seeding method of ultra-fine particles of metals such as iron. The growth of the fibers is controlled by the size of
optical and electron micrography are proposed for the microstructures present in carbon fibers spun from mesophase pitch. The failure mechanisms of those characteristic structures have been studied by breaking filaments in tensile and loops tests conducted under a viscous liquid to preserve the fracture surfaces.
233
252. Influence of processing variables on carbon fiber properties in a continuous process system T. Nagabhushanan, Th. Miiller, A. E. Simionato and J. L. Comes da Silva (Centro T&nico
256. Morphological rearrangements in conversion of acrylic fibers to carbon fibers. Oxidative stabilization M. K. Jain, P. Desai and A. S. Abhiraman (Geor-
Aeroespacial-IPD-PMR, 12.200~Scio Jo& dos Campos, ScZoPaulo, Brasil). Young’s modulus and tensile
gia Institute of Technology, School of Textile Engineering, Georgia Tech, Atlanta, GA 30332, U.S.A.).
strength of carbon fibres depend strongly on the preferred orientation of carbon layers in the fibres. The preferred orientation of these graphite layers can be increased by stretching the fibres during all stages of C-fibre production. In this paper the influence of the degree of prestretching and oxidation process parameters on intermediate products and on the properties of resulting C-fibres from PAN are presented.
Changes in orientational and lateral order and in mechanical properties occurring at different stages in the conversion of an acrylic polymer to carbon fibers are characterized. The results obtained so far indicate that significant morphological rearrangements precede the onset of reactions during oxidative stabilization. Based on the experimental results, a suitable morphological model for the precursor fibers has been identified. Results from experiments to produce precursor fibers with significantly higher order by deformation under conditions of “internal mobility” at high temperatures will also be presented.
253. Transverse properties of carbon and kevlar fibre composites J. F. Helmer and R. J. Diefendorf (Materials Engineering Department, Rensselaer Polytechnic Institute, Troy, NY 12181, U.S.A.). The prediction of
transverse laminae properties from those of constituents is an important aspect of better understanding overall composite behavior. Axial properties of fibres alone and in composites are both predictable from theory and are easily measured. The transverse properties, particularly of anisotropic fibres are almost impossible to generally predict and difficulties arise in direct experimental measurements off the fibre. Laminates of various filament volume ratios were constructed and measured for transverse CTE and transverse modulus so as to extrapolate a value for the fibre. 254. Structure and microtexture of some pitch-base fibres M. Guigon and A. Oberlin (Laboratoire Marcel Mathieu, ER 131 du CNRS, UER Sciences, 45046-Orleans Cedex, France). The three pitch-base
fibres studied more or less (graphitized) have lamellar radial texture, where defectives zones are distributed almost periodically, in bands parallel to the fibre axis (sometimes transversely). Defective zones are crumpled partially graphitized areas and turbostratic porous ones. The lamellar texture favors high Young’s modulus and low tensile strength, whereas defective zones do the reverse effect.
257. Stabilization of poly(acrylonitrile) copolymer precursor in air at 265% G. L. Collins, N. W. Thomas and G. E. Williams (Celanese Research Company, 86 Morris Avenue, Summit, NJ 07901, U.S.A.). An empirical kinetic
description of poly(acrylonitrile) copolymer stabilization has been developed which is based on the heat evolution from PAN materials during an isothermal treatment at 265°C. This approach avoids the difficulties encountered in attempting to extract kinetic information from scanning temperature methods such as DSC. The kinetic model developed has been useful in predicting the thermal behavior of partially stabilized copolymer fibers. 258. Carbon filaments on separated iron clusters J. Galuszkat and M. H. Back (Ottawa-Carleton Institute for Research and Graduate Studies in Chemistry, University of Ottawa Campus, Ottawa, Canada KIN 984). A new approach to the preparation of
metal surfaces for the catalytic formation of filamentous carbon is described. The procedure has allowed the production and observation (by SEM) of single, isolated carbon filaments. The filaments have been subjected to oxidation and to treatment with acid solution, which clearly identified the position of the metal cluster within the filament and the direction of growth of the filament.
255. Fracture behavior of mesophase carbon fiber C. B. Ng, G. W. Henderson, M. Buechler and J. L. White (Materials Sciences Laboratory, The Aerospace
TPresent address: Energy Research Laboratories, CANMET, Ottawa Canada, KlA OGI.
Corporation, P.O. Box 92957, Los Angeles, CA 90009, U.S.A.). Three structural models based on
259. Formation of vapor-grown carbon fibers by seed ing method of metal ultra-fine particles Morinobu Endo (Faculty of Engineering, Shinshu University, Wakasato, Nagano, 380, Japan). Kunio Komaki (Ohmachi Research Laboratory, Showa Denko Co., Ltd., Ohmachi, 398, Japan). Vapor-grown carbon fibers have been successfully grown by seeding method of ultra-fine particles of metals such as iron. The growth of the fibers is controlled by the size of
optical and electron micrography are proposed for the microstructures present in carbon fibers spun from mesophase pitch. The failure mechanisms of those characteristic structures have been studied by breaking filaments in tensile and loops tests conducted under a viscous liquid to preserve the fracture surfaces.