Tensile, Quasistatic and Dynamic Fracture Properties of Nano-Al₂O₃-Modified Epoxy Resin.

Epoxy resin, modified with different particle sizes (50 nm, 100 nm, 200 nm) and contents (1 wt %, 3 wt %, 5 wt %, 7 wt %) was manufactured. The mechanical behaviors of tensile, quasistatic fracture and dynamic fracture under SHPB (split Hopkinson pressure bar) loading were investigated. The dynamic fracture behaviors of the composites were evaluated by 2D-DIC (digital image correlation) and the strain gauge technique, and the fracture surface was examined by SEM (scanning electron microscope). According to the results, the tensile modulus and strength significantly increased for epoxy resin modified with 5 wt % Al₂O₃ of 50 nm. The quasistatic fracture toughness of modified epoxy resin increased with the particle content. However, the fracture toughness of epoxy resin modified with high content fillers decreased for particle agglomeration that existed in epoxy resin. The crack propagation velocity can be decreased for epoxy resin modified with particles under dynamic loading. The dynamic initiation fracture toughness of modified epoxy resin increases with both particle size and content, but when the fillers have a high content, the particle size effects are weak. For the composite under dynamic loading conditions, the toughening mechanism is also affected by particle size.