FRP composites based on different types of glass fibers and matrix resins: A comparative study

Flexural properties, impact energy, heat deflection temperature, and resistance to thermal and hydrothermal degradation of composites based on E‐glass and N‐glass fibers as the reinforcing agents, and epoxy, unsaturated polyester, phenolic, and epoxy‐phenolic resin systems as the matrix materials were studied and compared. As a reinforcing agent E‐glass fiber is superior to N‐glass fiber, particularly with respect to development of flexural strength and modulus, impact strength, and thermal resistance; N‐glass fiber, however, imparts to the composites substantially higher resistance to hydrothermal degradation under boiling conditions in different chemical environments. For use of both E‐glass and N‐glass fibers as reinforcing agents, the general order of resistance to hydrothermal degradation for the composites based on different matrix resins is epoxy > phenolic > unsaturated polyester resin. Incorporation of a low dose of a rubbery polymer, such as styrene butadiene rubber (0.1–0.2%) and liquid polybutadiene (0.5–0.75%), in unsaturated polyester resin as the matrix resin measurably enhances impact energy of the composite. © 1995 John Wiley & Sons, Inc.