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 (similar to 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.