Acoustic emission of the fracture behaviors of epoxy foam composites reinforced by bamboo fibers

The epoxy foam composites reinforced by unidirectional bamboo fibers were prepared and their mechanical property was examined by tensile test. The fracture morphology was observed by an environmental scanning electron microscopy (ESEM) and the fracture behaviors were quantitatively analyzed based on the acoustic emission (AE). The results indicated that the fiber reinforced foam (FRF) composites displayed much higher strength and toughness that are 131.3% and 223.5% higher than the pristine unfilled epoxy foam (PF), respectively. The mechanical behaviors of FRF during the fracture process were mainly the failure of porous matrix covered on the fiber interface, which took a proportion of 72.2%. The fiber dissociations and fiber breakage took 19.6% and 8.2%, respectively. The structure-property relationships bridged by AE and the fractography were investigated, and the strategies on strengthening and toughening the porous polymer composites were discussed.