Study on Thermal and Lap Shear Characteristics of Epoxy Adhesive Loaded with Metallic and Non-Metallic Particles

Influence of loading of Al2O3, Al, and Cu particles (0.5-5 mu m) in an epoxy adhesive has been studied in reference to thermal stability and single lap shear joint properties of the resulting composites. The SEM studies on state of dispersion of particles in the epoxy adhesive largely reveal their homogeneous distribution in the matrix up to an optimum level of loading. The thermal stability of the neat epoxy adhesive and the epoxy-particulate composites has been studied by the TGA/DTG analysis. The thermal stability and single lap shear joint strength of epoxy-particulate composites for 10 wt% loading of Al2O3, Al, and Cu particles in the epoxy matrix show significant improvement with respect to those of the neat epoxy adhesive as well as the adhesive joint where the addition of Al gives maximum benefit in this regard. The fracture surfaces of the epoxy-particulate composites observed under SEM reveal the presence of fracture mechanisms such as shear band formation, void growth, crack deflection, crack bifurcation, and plastic shear deformation.