Morphology, tensile properties, and fracture toughness of epoxy/Al2O3 nanocomposites

Abstract Epoxy/Al 2 O 3 nanocomposites were prepared using an epoxy resin, diglycidyl ether of bisphenol A, and cured with a polyoxypropylene diamine (Jeffamine D‐400). Transmission electron microscopy and wide angle X‐ray diffraction were employed to reveal the morphology of epoxy/Al 2 O 3 nanocomposites. Dynamic mechanical analysis results showed that the storage modulus and the glass transition temperature ( T g ) of epoxy were improved. Tensile strength and Young's modulus also increased with increasing Al 2 O 3 loading. Fracture toughness, as indicated by the stress intensity factor, K Q , was determined using single edge notch bending method, and 40% increase in K Q was observed with only 2 vol % Al 2 O 3 . Scanning electron microscopy study of fracture surface showed a rather smooth and flat morphology for neat epoxy. However, massive plastic deformation was observed for epoxy/Al 2 O 3 nanocomposites, leading to the significant increase in fracture toughness. The influence of spherical Al 2 O 3 nanoparticles on thermophysical properties of epoxy was discussed and compared with that of sheet‐like nanoclays. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1466–1473, 2006