Fe3O4-Nanoparticle-Doped Epoxy Resin as a Detachable Adhesive by Electromagnetic Heating for GFRP Single-Lap Joints

An adhesive based on a Fe3O4-nanoparticle (MNP)-doped epoxy resin was proposed for the development of detachable adhesive joints with GFRP substrates. The analysis of cryofractures showed that the increasing MNP content promotes a higher presence of larger aggregates and a lower sedimentation of nanoparticles due to the higher viscosity of the mixture. In this regard, the inclusion of expandable microspheres (MS) induces a more uniform dispersion of MNPs, reducing their sedimentation. The capability of the proposed adhesives for electromagnetic (EM) heating was also evaluated, with increases in temperature of around 100 degrees C at 750 A, enough to reach the T-g of the polymer required to facilitate the adhesive detachment, which is around 80 degrees C. Finally, the lap shear strength (LSS) of 14 and 20 wt.% MNP samples was evaluated in a single-lap shear joint with simultaneous EM heating. The LSS values were reduced by 60-80% at 750 A, thus promoting successful adhesive joint detachment under EM heating.

Automated summary

This study proposes an adhesive based on Fe3O4 nanoparticle-doped epoxy resin for detachable adhesive joints with GFRP substrates. The results show that increasing the MNP content promotes larger aggregates and reduces nanoparticle sedimentation. The addition of expandable microspheres allows for a more uniform dispersion of MNPs and enhances the adhesive's electromagnetic heating capability. Furthermore, the lap shear strength of the adhesive is significantly reduced under EM heating, facilitating successful detachme