GFRP, Glass Fiber Reinforced Polymer
Index
Fiberglass is a low cost composite material made from glass fibers in a polymeric matrix (gfrp). The fibers provide the main load carrying capability of the material and the polymer serves to protect the fibers and permit load transfer to them. The photograph shows a cross section of a gfrp material where the fibers were woven into a fabric before being impregnated with the polymer. The lowest cost form of the material uses chopped fibers that are randomly oriented in the polymeric matrix.  The matrix may be an epoxy, a polyamide such as nylon 6-6, or a polycarbonate. Selection is based on cost/ performance considerations. Water uptake is an issue in the performance of the gfrp. The water absorption in 24 h at 20 C and 100% relative humidity is 0.03% for the polypropylene, 1.3% for the 6-6 nylon, and 0.1% for the polycarbonate. For the fibers, E-glass has a specific Young's modulus of 30 GPa/Mg.m3.
From: Hull, "An Introduction to Composite Materials," Cambridge (1992)