Novel glass fiber-reinforced composites having a UV and peroxy curable fluoropolymer matrix

Novel glass fiber-reinforced composites were prepared from E-glass fibers and perfluoropolyether (PFPE), polyurethane acrylate, and methacrylate resins. The PFPE resins were synthesized by a two-step process and formulated with reactive acrylic diluents obtaining two compositions with different viscosity and fluorine content. These formulations were photocrosslinked by UV-A radiation and characterized by tensile and dynamic-mechanical properties as well as by impact resistance. The two UV cured fluoropolymer compositions are high modulus (> 1 GPa), polyphasic materials characterized by a fracture toughness higher than conventional polymer matrices, like epoxies and unsaturated polyesters. Unidirectional laminate composites were also prepared by hand lay-up and crosslinked both photochemically and thermally. Mechanical characterization of glass fiber-reinforced composites was carried out by tensile tests and shear adhesion measurements, showing a good fluoropolymer-glass adhesion strength (ca. 9 MPa). Surface characterization of composites by static contact angle measurements allowed the calculation of the total surface tension gamma(s) according to Wu's harmonic mean approximation. Surface tension is very low (< 20 mN/m) suggesting a preferential stratification of PFPE segments at the material-air interface.