Adhesion performance of magnetite-reinforced epoxy copolymer adhesives evaluated using multi-criteria decision-making methods

Abstract

This study investigates the adhesive performance of epoxy-based copolymers prepared from glycidyl methacrylate (GMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA), cured with 4,4′-methylenedianiline (MDA) and reinforced with magnetite (Fe ₃ O ₄ ) nanoparticles. The influence of PEGMEMA side groups and nanoparticle incorporation on the mechanical properties of single-lap aluminum joints was systematically evaluated. Results demonstrated that oxygen-rich PEGMEMA segments enhanced interfacial adhesion and improved shear strength and shear modulus. In contrast, higher PEGMEMA incorporation reduced the effective crosslinking density, leading to a deterioration in the mechanical performance of the copolymers, as evidenced by lower shear strength and shear modulus values. A significant increase in polymer ductility was observed with higher PEGMEMA ratios, which was attributed to increased chain mobility and flexibility. Furthermore, the addition of magnetite nanoparticles (1–4 wt %) to the adhesive formulation enhanced adhesive strength, with the P1 copolymer containing 2 wt % magnetite exhibiting the highest performance. In addition, three Multi-Criteria Decision-Making (MCDM) techniques were used to identify monitoring indicators with minimal dispersion and strong correlations with shear strength, elastic shear modulus, and displacement. These indicators exhibit predictive capability for mechanical properties, potentially reducing the need for shear testing.