Effect of TiO₂ surface treatment on the mechanical properties of cured epoxy resin

Mechanical properties of epoxy resin toughened with two different submicron particles of TiO₂ at different weight fractions (1, 3, and 5%, respectively) were investigated. The first TiO₂ particles are surface treated with Al₂O₃–SiO₂, and the second are surface treated with Al₂O₃–ZrO₂. The composites were characterized by tensile, flexural, pull off and abrasion tests, followed by X-ray photoelectron spectroscopy and scanning electron spectroscopy of the fracture surfaces. A small amount of TiO₂ (~1%) submicron particles improves the flexural, abrasion and pull-off strengths, while amounts up to 5% significantly enhance tensile properties only. TiO₂ particles surface treated with Al₂O₃–ZrO₂ produce an epoxy composite with higher strength and weight loss but lower pull off strength and more brittle than that prepared with Al₂O₃–SiO₂ particles. The TiO₂ particles surface treated with Al₂O₃–SiO₂ have a higher adherence to the epoxy composite matrix than the particles treated with Al₂O₃–ZrO₂ as shown by scanning electron spectroscopy.