Glass-reinforced plastic
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Glass-reinforced plastic (GRP), is a composite material or fibre reinforced plastic made of a plastic reinforced by fine fibers made of glass. Like graphite-reinforced plastic, the composite material is commonly referred to by the name of its reinforcing fibers (fiberglass), an example of part-for-whole metonymy. The plastic is most often polyester or vinylester, but other plastics, like epoxy (GRE), are also sometimes used. The glass is mostly in the form of chopped strand mat (CSM), but woven fabrics are also used.
GRP/GRE is a versatile material with many uses. Although GRP was originally developed in the UK during the Second World War as a replacement for the molded plywood used in aircraft radomes (GRP being transparent to microwaves) its first main civilian application was for building of boats, where it gained acceptance in the 1950s, and now plays a dominant role. But its use has broadened over the years, and it is used extensively within the automotive and sport equipment sectors, although its use there is being taken over by carbon fiber because of its lower weight. GRE is also used to make hot tubs, pipes for drinking water, sewers, chemicals, and so on.
Advanced manufacturing techniques such as pre-pregs and fibre rovings extend the applications and the tensile strength possible with fibre-reinforced plastics.
GRP is also widely used in the telecommunications industry for shrouding the visual appearance of antennas, due to its RF permeability and low signal attenuation properties. It may also be used to shroud the visual appearance of other equipment where no signal permeability is required, such as equipment cabinets and steel support structures, due to the ease with which it can be moulded, manufactured, and painted to custom designs, to blend in with existing structures or brickwork.
Examples of GRP usage
- Thorpe Park's 'Tidal Wave' ride uses reinforced GRP for its 4 tonne boats.
- Sailplanes have been built almost exclusively of reinforced plastic since the mid-1960s, with carbon, aramid and other fibres taking the place of glass in modern competition sailplanes, and with extensive use of high strength rovings.
- The hollow rotor blades of large wind turbines are usually made of GRP.
- Kayaks are often made of chopped strand mat and polyvinylester because they are strong, durable, and are easily shaped.