High-modulus type fibers

High strength carbon fibers (Type II) are much more abrasive than the high modulus (Type I) variety [74]. Carbon-carbon composites have high compressive strengths and stiffnesses and friction and wear properties can be modified by the introduction of additives [75]. 

Unfortunately, Ni catalyzes the crystallization of carbon fibers when heated and the high modulus carbon fibers are more resistant to recrystallization than the high strength types [41,42]. The effect of 1 h of heat treatment in the range 800-1300°C in Ar on the tensile strength, modulus and recrystallization of electroless Ni plated carbon fibers was determined by Warren [105], who showed that the high modulus PAN type carbon fibers were less affected. 

Figure 22.3 Elastic constants of 0 angle ply of Type I high modulus carbon fiber epoxy laminates. At 9 = 0°, Eai=Eii Ea2 = and 6312= G. The maximum value of Gai2 occurs at 9 = 45°. Source Reprinted from Sinclair JH, Chamis CC, Proceedings of the 35" SPI/RP Annual Technology Conf, Paper 12A, Society of the Plastics Institute, New York, 1980.

Figure 22.4 Interlaminar shear stress as a function of ply angle for Type I high modulus carbon fiber epoxy resin laminate tested in uniaxial tension in x-direction. The maximum interlaminar shear strength occurs at 0 = 35° and the stresses are zero at 0, 60 and 90°. Source Reprinted with permission from Pipes RB, Pagano NJ, Interlaminar shear stress in composite laminates under axial tension, J Composite Mater Sci, 13, 2131-2136, 1978. Copyright 1978, Sage Publications.

Three types of Kevlar aramid fibers are available a high-tensile-strength, high-modulus type for reinforcement of plastic a similar fiber for use in ropes, cables, coated fabrics, and protective clothing and a third type designed to reinforce rubber products such as tires, belts, and hoses. 

Figure 4. Tensile fracture surfaces for three structural types of high-modulus mesophase carbon fibers (E = 100 Mpsi ...

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