Study on the Effect of Silica Submicron Particle Size and Content on Fracture Toughness of Filled Epoxy Resin

Epoxy resins with excellent physical, mechanical properties and electrical insulation are used in a wide variety of fields. In order to overcome their inherent brittleness, silica particles, one of the most intriguing inorganic particles, have been extensively used as modification fillers of epoxy composites, and various toughening mechanisms have been brought out. On the base of former studies and theories, different sizes and contents of silica particles on submicron Scale, ranging from 100 nm to 1 pm and 0 to 60 wt.% respectively, were used in this study to toughen epoxy resins, and the effect of particle size and filler content on the mechanical properties, especially fracture toughness (K-IC) of Silica-epoxy composites were investigated. The size and morphology of silica particles were observed by scanning election microscopy (SEM). Fracture toughness (K-IC) of silicaepoxy composite was measured by a single-edge notch threepoint-bending (SEN3PB) test. The fracture surfaces were observed by SEM to investigate and determine the toughening mechanisms of silica-epoxy composites. The effect of filler size and content on _ fracture toughness has_ been _ further investigated and understood.