High Performance Synthetic Fibers for Composites (1992) / Chapter Skim
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1 High-Performance Synthetic Fibers for Composites
1 High-Performance Synthetic Fibers for Composites
Pages 9-20
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From page 9... ...
This class of advanced composite materials exhibits physical properties that are vastly superior to those of the matrix material alone. These new composite materials are vital to the defense posture of the United States, but their future impact on the growth of our ~on~mv mom he STOW mm'" important.
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From page 10... ...
_ ~ Thus, both performance and wet economy can benefit from increased utilization of these materials. Since high-performance fibers are extensively used in aircraft structures, it is imperative to have a sound foundation in fiber technology and domestic production of these high performance fibers if the United States is to remain a world leader in aircraft production.
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From page 11... ...
Likewise, metals such as aluminum, steel, copper, or tungsten are adequate for lightweight structural components, tooling, electrical conductors, and lame filam~nt.c: r~c:n~rti~r~1 or ~ ~ ~ factor, the _ _ window glass, structural bricks, and cement blocks is considered satisfactory. However, in many applications where performance is the controlling factor (i.e., aerospace, transportation, underwater vessels)
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From page 12... ...
While the strength of an injection-molded polyamide plate in only O.08 GPa, the tensile strength of the same polymer is over five times greater when it is extruded into a textilegrade fiber. If this same textile-grade fiber is stretched in an extensive drawing process, an industrial-grade tire cord fiber can be produced that is 10 times stronger and nearly twice as stiff as the injection-molded polymer.
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From page 13... ...
Thus, in addition to forming a more perfect structure, brittle materials in fiber form contain smaller flaws, further enhancing the tensile strength.2 Unfortunately, the increased tensile strength of fibers does not come without a penalty. Fibers, like rope, display this increased strength only when the load is applied parallel to the fiber axis.
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From page 14... ...
synthetic fibers industry also grew dramatically. In 1988 the industry produced over 9 billion pounds of synthetic fibers for industrial and textile end uses, 3 accounting for about 24 percent of the total world production.
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From page 15... ...
To increase productivity and reduce manufacturing and processing costs, synthetic fibers are normally produced and sold in multifilament bundles. As Figure 1.3 shows, there is often a trade-off between the size of this bundle of fibers, final fiber properties, and fiber cost, even for current highperformance fibers.
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From page 16... ...
FIBE:R-REINFORCED COMPOSITES In a composite material the fibers are surrounded by a thin layer of matrix material that holds the fibers permanently in the desired orientation
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From page 17... ...
When high-performance fibers, such as carbon or polyaramide, at fiber loadings typically greater than 45 percent, are surrounded by the same plastic matrix, the material becomes an "advanced composite." Thus, in many ways, advanced composite materials represent a major breakthrough for a composite material technology that has been extensively utilized for many years. It is the added strength and stiffness of these new reinforcing fibers that allows the new advanced composites to out perform current metal and metal alloy structures.
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From page 18... ...
properties Toughness Electrical and thermal conductivities Thermal expansion Stiffness Resistance to corrosion ~ Better resistance to creep at high temperatures · Substitution for critical or strategic materials · Creation of multipurpose or "smart" structures The recently published Handbook on Composites is an important reference for current information on composites and basic materials used in composites, including fibers and fiber properties useful in the design or development of composites. Also, an especially pertinent broad review of present materials and needs for the future was published in the October, 1986, issue of Scientific American.9 Projections for High Performance Fibers The fiber research needed will depend on both the application and the fiber in question.
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From page 19... ...
Because the composites industry is highly international, extensive fiber science/technology bases also exist in Western Europe and Japan, where there are strong commitments to support the development of high-performance fibers. Unless steps are taken to strengthen our domestic fiber science/technology base, to facilitate its industrial application, and to broaden the industrial base for high-performance fibers, the United States might lose its present competitive position in this key industry.
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From page 20... ...
1191-1220, Sept.-Oct., 1985. Presentations at Federal Sector Briefing, "Advanced Composites 89; An Industry Overview," Suppliers of Advanced Composite Materials Assn.
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