Continuous fiber reinforced glass composites processing

P. Card and G. D. Soraru, Sol-gel processing of continuous fiber reinforced composites by the liquid infiltration and pyrolysis (LIP) method, in Innovative Processing and Synthesis of Ceramics, Glasses and Composites, N. P. Bansal, K. V. Logan, and J. P. Singh (Eds), Ceramic Transactions, Vol. 85, 1997, pp. 405-416. The American Ceramic Society, Westerville, Ohio, USA. 

Oxide fibers find uses both as insulation and as reinforcements. Glass fibers, based on silica, possess a variety of compositions in accordance with the characteristics desired. They represent the biggest market for oxide fibers. Unlike other oxide fibers, glass fibers are continuously spun from the melt and are not used at temperatures above 250°C. Short oxide fibers can be melt blown whilst other aluminasilicate and alumina based continuous fibers are made by sol-gel processes. Initial uses for these fibers were as refractory insulation, up to 1600°C, but they are now also produced as reinforcements for metal matrix composites. Continuous oxide fibers are candidates as reinforcements for use up to and above 1000°C. 

The surface treatment chemistry of glass fiber is normally tailored to match the product function. Reinforcement size chemistries must be compatible with a multitude of processes and with the composite material end-use performance criteria. Processes such as injection molding require chopped fibers with compatibility for thermoplastic compounds. Filament winding and pultrusion require continuous fibers with utihty in thermoset and thermoplastic compovmds. Typically three basic components cue used with glass size chemistries a film former, lubricant, and coupling agent. Readers are directed to the patent literature or [1] and [2] for more specific details. 

For composite reinforcement appUcations such as fiber-reinforced polymers (FRPs), also known as glass-fiber-reinforced plastic (GRP), the fiber can be supplied as chopped strands (at several standard lengths, from 3 to 12 mm) or continuous roving, which can be chopped at the point of composite manufacture. It can also be supplied as milled fiber, with lengths of about 0.2 mm. Roving can be woven into a wide variety of two-dimensional and three-dimensional shapes for polymer impregnation. The relationships between the various process steps and the resulting types of reinforcement fiber products are shown in Fig. 6.41. 

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