PROCESSING AND CHARACTERIZATION OF POLYESTER-ALUMINUM AND POLYESTER-ALUMINA NANOCOMPOSITES

摘要

Micron- and nanometer-sized aluminum and alumina particles are used as reinforcements to enhance the fracture toughness of a highly crosslinked, nominally brittle, thermosetting unsaturated polyester resin. Both particle size and particle volume fraction are systematically varied to investigate their effects on the fracture behavior and the fracture toughness. Furthermore, the particle-matrix interface strength is controlled using appropriate treatment by an organofunctional silane. It is observed that the overall fracture toughness of the composite is strongly influenced by the size of the reinforcement particles. Nanometer sized particles lead to significantly greater increases in the fracture toughness provided particle dispersion is maintained and the particles are strongly bonded to the polyester matrix. Scanning electron microscopy of the fracture surfaces is employed to establish crack front trapping as the primary extrinsic toughening mechanism, and to investigate the effect of particle-matrix adhesion on the fracture process.