MWCNTs toward superior strength of epoxy adhesive joint on mild steel adherent

In this work, the characteristics of the lap shear joints of MWCNT-epoxy adhesive on mild steel adherend are investigated. In this paper, multiwall carbon nanotubes (MWCNTs) are homogeneously and cluster-freely reinforced in epoxy matrix by simultaneously applying ultrasonic waves and an axial flow impeller on epoxy resin to develop toughened epoxy adhesives. Here, we describe details pertaining to mild steel surface morphology, the bond line thickness of the adhesive, the wettability of MWCNT-epoxy resin on the mild steel surface and the impact of the presence of MWCNTs in epoxy resin on the performance of lap shear joints. The experimental observations indicate that the reinforcement of MWCNTs in epoxy with uniform cluster-free dispersion and a change in the morphology of the mild steel adherend significantly improve the strength of lap shear joints and change their failure mode. The inclusion of 0.75 wt% of MWCNTs in epoxy adhesive resulted in the largest enhancement in the lap shear strength and as the weight percentage of MWCNTs increased from 0.75 wt%, the lap shear strength began to degrade.