Fiber-reinforced plastics (FRP), also known as fiber-reinforced polymers, are a category of composite plastics specifically using fiber materials to mechanically augment the elasticity and strength of the plastic. They consist of a polymer matrix – the original plastic which is usually tough but weak – which is blended with a reinforcing material to yield a final product with the desired material or mechanical properties.
The polymer matrix is developed via a step growth or addition polymerisation and is usually an epoxy, vinylester or polyester thermosetting plastic. FRP are chiefly created through molding processes, where a mold is used to place a fiber preform – containing balsalt, carbon, an aramid, or even glass – into the matrix. Occasionally asbestos, wood or paper can be incorporated instead.
After wetting and curing, the fibers and matrix take on the shape of the mold. The resulting structure has a greater mechanical strength and elasticity than the original plastic, toughened by the addition of the reinforcing fiber or filament, which plays a critical role in differentiating the parent polymer from the FRP.