Transparent fiber glass reinforced composites

We present here studies targeting the processing of cross-woven, fiber-glass reinforced epoxy–resin composites with ≈50 wt.% loadings of 0/90 cross-woven fiber glass mats of potential use as low-cost, high strength, light weight materials for safety/sports goggle, motorcycle helmet or window armor applications. Epoxy–resin systems were developed that match the refractive index (RI) of S-glass (1.521–25) fiber mats with woven densities of ≈0.012 g/cm2. The fiber glass mats were impregnated with the RI matched matrix and cured under pressure to produce composites with high transparencies, up to 84%. Moreover their mechanical properties are superior to those reported for traditional fiber glass reinforced composites exhibiting tensile strengths of up to 333 ± 12 MPa and flexural strengths of up to 436 ± 28 MPa. The improved values likely result from the elimination of large surface flaws through the use of very smooth mold surfaces. The current composites exhibit slightly blue or yellow chromatic dispersion resulting from incomplete RI matching at all visible wavelengths.