An Adhesive Composite Material from Magnetite and a Methacrylate Copolymer with Epoxy and PEG Side Groups

Abstract This article reports the synthesis, characterization, and adhesive application of poly(GMA‐ co ‐mPEGMA) copolymers with different monomer feed ratios. 4,4′‐Methylenedianiline (MDA) was used as the hardener. The effects of the presence of mPEG side units in the epoxy copolymer and magnetite (Fe 3 O 4 ) nanoparticles on the mechanical properties of single‐lap steel joints were investigated in detail. The presence and the percent ratio of oxygen‐rich mPEG side groups in the copolymers promoted the shear Young's moduli and the ultimate strength of their cured counterparts to some extent. On the other hand, the higher ratios of mPEGMA monomer residues compromised the crosslinking density of the cured polymeric networks and, therefore, their shear moduli values. Besides, the ductility of the crosslinked polymers was greatly enhanced with the increasing ratio of mPEGMA in their structures. The optimum ratio of magnetite nanoparticles was found to be 2% (out of the mass of organic solid material). The presence of magnetite nanoparticles markedly increased both the ultimate shear strength and the displacement values of the cured polymers. Besides, they exhibited strain‐induced hardening due to the formation of more ordered structures during the plastic deformation process.