Explain a) Fiber glass reinforced composite. b) Carbon fiber reinforced composite.

a) Glass-fibre reinforced composite (GFRP / fibreglass)

• Constituents: continuous or chopped glass fibres (E-glass, S-glass), about 3–20 µm in diameter, as the dispersed phase, in a polymer matrix of polyester, epoxy or vinyl ester resin.
• Preparation: hand lay-up, spray-up, filament winding or pultrusion, followed by curing of the resin.
• Properties: high specific strength; good corrosion and chemical resistance; electrical insulator; cheap. Limitations: low stiffness (modulus) compared with CFRP, and it cannot be used above about 200 °C.
• Applications: boat hulls, car body panels, pipes and storage tanks, water tanks, sports goods, helmets, circuit boards, wind-turbine blades, roofing sheets.

b) Carbon-fibre reinforced composite (CFRP)

• Constituents: carbon or graphite fibres (made by pyrolysis of polyacrylonitrile or pitch) in a polymer matrix, usually epoxy.
• Properties: very high strength and very high modulus (stiffness) at low density, so the specific strength and stiffness are the highest of common composites. It keeps its strength at high temperature, has low thermal expansion, resists fatigue and corrosion, and conducts electricity. Limitations: high cost and brittle failure.
• Applications: aircraft and spacecraft structures, racing cars, bicycle frames, tennis rackets, golf clubs, fishing rods, wind-turbine blades, prosthetics, pressure vessels.