Glass-graphite fibers

Risilan AZM Polyamide-12 with glass/graphite fibers, PA-12 Elf Atochem... 

Glass/Graphite Fibers Reinforced Epoxy Resins... 

High performance composites may be laminates wherein veils of carbon fiber ate treated with an epoxy resin, stacked up to the desired final product thickness, and then laminated together under heat and pressure (see Composite materials Carbon and graphite fibers). Simply mixing together carbon or glass fibers and polymeric resins to form a reinforced plastic leads to a composite material, but this is not a laminate if not constmcted from discrete phes. 

Composites. The history of phenoHc resin composites goes back to the early development of phenoHc materials, when wood flour, minerals, and colorants were combined with phenoHc resins to produce mol ding compounds. In later appHcations, resin varnishes were developed for kraft paper and textile fabrics to make decorative and industrial laminates. Although phenoHcs have been well characterized in glass-reinforced composites, new developments continue in this area, such as new systems for Hquid-injection molding (LIM) and sheet-molding compounds (SMC). More compHcated composite systems are based on aramid and graphite fibers. 

The water hberated during the cure has no apparent effect on the composite properties. Glass-filled composites prepared in this manner retain mechanical properties at elevated temperatures as well as solvent and flammabiUty resistance (88). PhenoHc-graphite-fiber composites that exhibit superior mechanical properties have also been prepared by this process. 

For friction material appHcations, composite materials (qv) comprising glass or metallic fibers with other minerals have been developed. In such appHcations also, aramid and graphite fibers are effective, although the cost of these materials restricts their use to heavy duty or high technology appHcations (see Carbon fibers). 

A polymer blend is a physical or mechanical blend (alloy) of two or more homopolymers or copolymers. Although a polymer blend is not a copolymer according to the above definition, it is mentioned here because of its commercial importance and the frequency with which blends are compared with chemically bonded copolymers. Another technologically significant material relative to the copolymer is the composite, a physical or mechanical combination of a polymer with some unlike material, eg, reinforcing materials such as carbon black, graphite fiber, and glass (see Composite materials). 

Bismaleimide, BMI/graphite fibers (1098) Phenolic/glass fibers (45 %)... 

Gulino, R. and Phoenix, L. (1991). Weibull strength statistics for graphite fibers measured from the break progression in a model graphite/glass/cpoxy microcomposites. J. Mater. Sci. 26, 3107-3118. 

Asbestos fibers are found worldwide in many products as reinforcement in cement water pipes and the inert and durable mesh material used in filtration processes of chemicals and petroleum, for example. However, asbestos is not the only inorganic fiber in use today. Synthetic inorganic fibers abound. Glass fibers have replaced copper wire in some intercontinental telephone cables. Fiberglas (a trade name) has become the insulation material of choice in construction. Carbon and graphite fiber composites are favored materials for tennis racket frames and golf clubs. Fibrous inorganic materials have become commonplace in our everyday lives. 

This brief summary of the composition and structural characteristics of glass fibers, whiskers, and carbon and graphite fibers illustrates the ranges of synthetic inorganic fibrous materials. The purposes of the construction of these materials is to capitalize on the physical and chemical advantages of the fibrous morphology, size, and state. 

Different kinds of carbon-intense fibers are used, the most common being carbon and graphite fibers, and carbon black. As is the case with fibrous glass, surface voids are present. Carbon-intense fibers are often surface-treated with agents such as low molecular weight epoxy resins. Such surface treatments also aim at increasing the fiber-matrix adhesion. 

Iodine is packed and supplied in polyethylene-lined fiber drums or high sihcon iron, Hastelloy B, or lead coated steel containers. Glass, graphite and acid-proof bricks are very suitable for storing iodine and its solutions. 

Poisson s ratio for the off-axis loaded lamina, v y, can also be derived. The relative tensile modulus, E jEi, shear modulus, Gj jGi2, and Poisson s ratio, v y, are plotted as a function of the angle of rotation, 9, for a glass-fiber-reinforced epoxy lamina and a graphite-fiber-reinforced epoxy lamina in Figures 5.120a and 5.120b, respectively. 

Figure 5.120 Elastic constants for unidirectional (a) glass fiber reinforced epoxy and (b) graphite fiber-reinforced epoxy laminae. Reprinled, by permission, from P. C. Powell and A. J. I. Housz, Engineering with Polymers, pp. 222, 223. Copyrighl 1998 by Stanley Thorned Publishers.

The relevant properties of these materials for the torsional-mechanical analysis are listed in Table 8.11. On the basis of specific elastic modulus and specific shear modulus, the best materials are the graphite-fiber-reinforced epoxy resin, followed by either of the alloys, then the Kevlar fiber-reinforced epoxy. The chopped glass sheet molding compound is obviously not a good choice. 

The standard ASTM D2585 filament wound pressurized bottle test method utilizes a 0.15-m (5.75-in.)intemal diameter filament wound bottle as the test article. This standard test method (with variation in bottle sizes) has been used extensively by the rocket motor industry [47-50] to evaluate glass, aramid, and graphite fiber composite vessel performance. This test method has generally shown good results, but is a relatively expensive test method. Testing of one 0.5-m (20-in.) diameter bottle can cost up to 20K. Other disadvantages are ... 

The value of the epoxy resins lies in their reactivity with a variety of chemical groups. This enhanced reactivity also means that the surface chemistry of the reinforcement which the epoxies are cured against, can alter the local structure in the interphase regionJl). The most common reinforcement surfaces cured in contact with the epoxies are carbon/graphite fibers, glass fibers, aramid fibers and metal oxides. The surface chemistry of these reinforcement surfaces is quite diverse and in many cases can be the reason for alteration of the interphase epoxy structure as compared to the bulk. 

Inorganic membranes Glass hollow fiber Glass hollow fiber Graphite, oxidized Schott A Gen. Westinchouse (Union Carbide Comp.) SO 98 80 120 41 0.5 0.5 ... 

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