The Composite Materials

Fiberglass Reinforced Plastic is a composite material. Composites are an engineering material compromising of a thermoset resin (the matrix) and a fiber reinforcement. The liquid resin is combined with the fiber reinforcement in the manufacturing process and cures into a solid laminate. There are many types of composite resins and reinforcements and each of these imparts specific properties to the GRP product.

There are at least 6 major family groups of resins used in composite fabrication. These include: Polyester, Vinyl Ester, Modified Acrylic, Epoxy, Phenolic, and Urethane resin systems. The list goes on, however, the important point to note is that each of these resins has specific performance characteristics. If corrosion is an issue, a vinyl ester resin would be a good candidate. If high strength is critical, an epoxy might be the resin of choice. In the realm of polyester resin alone, specific formulations will be used. If cosmetics are an issue, enhanced corrosion resistance is required, elevated temperatures will be encountered, or cost is an over-riding factor, then the particular resin needed for that application is used. The resin system is selected based on the functional and cost requirements of the product.

The Reinforcements

There are also a number of reinforcement fibers used in composites. Glass fiber is used in over 90% of all composites. However, if required, advanced fibers such as Kevlar of carbon fiber are available. In the realm of glass fiber there are many "styles" of reinforcement. Depending on the molding process and the strength requirements of the product there are many options. Glass fiber is available in random fiber orientation in the form of chopped strand mat.

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