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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. |
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