Value-In-Use of Composite Reinforcing Fibers

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Value-In-Use of Composite Reinforcing Fibers Frederick T. Wallenberger PPG Industries, Inc., Glass Technology Center Fiberglass Science and Technology Pittsburgh, PA 15230-2844, U.S.A.

ABSTRACT This paper analyzes the value-in-use of advanced fibers, especially of those, which are used to reinforce polymer matrix composites. Of particular interest in this regard are some recent fibers, such as (1) pure silica fibers derived from water glass, (2) oxynitride glass fibers, having the same high elastic modulus as SM carbon fibers, and (3) Kenaf, as well as other natural plant fibers, which are beginning to find commercial use in selected automotive composites. INTRODUCTION Science is driven by fundamentally new conceptual insights. It results in new theory and in new technology. Materials science and materials technology leads to new commercial applications, but only if the new technology offers a higher value-in-use than the technology it replaces. New technology must yield the same performance at lower cost than the one it replaces, or afford superior, previously unattainable performance at appropriately higher cost. In this symposium, new science and new technology co-equal. New technology is driven by actual and/or perceived needs of society, and by the expectation that it would lead to a better tomorrow. Value-in-use drives the search for a lighter composite part for automobiles to reduce the gasoline consumption, or for a more effective computer wire board with low dielectric constants to usher in completely new communications capabilities. The present paper bridges recent advances in the disciplines of inorganic fibers [1], composite reinforcing fibers [2], fiber glass reinforcements [3] and glass fibers for electronic applications [4]. VALUE-IN-USE Together new materials science and new materials technology can lead to new commercial uses, but only if the new technology offers a higher value-in-use than the technology it replaces. New technology must afford the same properties or performance at a lower cost than the technology it replaces, or superior and previously unattainable properties as well as capabilities at commensurately higher cost. In this context, cost becomes a materials property. Depending on design requirements, it is therefore possible to select a specific compositereinforcing fiber that will yield the sought-after balance of composite properties at the lowest possible cost. A fiber that meets or exceeds the design requirements for a commercial composite part with a low selling price has high value-in-use.

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THE FUNCTION OF REINFORCEMENTS Composite reinforcing fibers are a key component of polymer matrix, ceramic matrix and metal matrix composites. They impart high strength and stiffness to the matrix material, which they modify, and offer other equally desirable properties such as low dielectric constants, and high temperature, impact and/or creep resistance, especially at elevated temperatures. Reinforcing fibers differ from each other by virtue of their chemical composition, structur