The bonding performances of carbon nanotube (CNT)-reinforced epoxy adhesively bonded joints on steel substrates

Carbon nanotubes (CNTs) are generally considered as a promising particle reinforcement of incorporating advanced properties and characteristics into epoxy nanocomposites. This paper investigated the bonding performances of CNT-reinforced epoxy adhesively bonded joints on steel substrates using the single lap shear (SLS) tests. The bonding performances (including bonding strength, fracture strain, toughness, and failure mode) were studied with three adhesive thicknesses (1 mm, 0.5 mm, and 0.25 mm) and three CNT weight fractions (0%, 0.375%, and 0.75%). The experimental results indicated that thinner bondlines and higher CNT additions could significantly improve the bonding performances and modify the failure mode of CNT-reinforced epoxy adhesively bonded joints. However, the effects of adhesive thickness became less significant with the increase of CNT weight fractions. In addition, the plastic behaviour of CNT-reinforced epoxy, CNTs pulling-out, and the aggregation of CNTs were observed by scanning electron microscopy (SEM) image analysis on the fracture surfaces of CNT-reinforced epoxy adhesively bonded joints, indicating the potential effectiveness of the CNT reinforcement.

Automated summary

Thinner bondlines and higher CNT additions can significantly enhance the bonding performances and modify the failure mode of CNT-reinforced epoxy adhesively bonded joints. However, the effects of adhesive thickness become less significant with the increase of CNT weight fractions. Moreover, scanning electron microscopy (SEM) analysis shows the potential effectiveness of CNT reinforcement in improving the bonding performances.