Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE The preparation and mechanical testing procedure of single-lap adhesive joints.

ABSTRACT
In this study, poly(glycidyl methacrylate) (PGMA) and poly(GMA-co-MMA) copolymers were synthesized using different monomer feed ratios. Composite adhesives based on PGMA and poly(GMA-co-MMA) were prepared by incorporating heat-treated boric acid (HTB), heat-treated ulexite (HTU), TiO2, and Fe3O4 at concentrations of 1, 2, and 4 wt%. The polymers were characterized by FTIR and 1H NMR. Thermogravimetric analysis (TGA) was employed to assess the thermal stability of the synthesized polymers and confirm the filler content of their adhesive formulations. Furthermore, the influence of filler concentration on the shear strength of single-lap joints bonded with PGMA and poly(GMA-co-MMA) adhesives was systematically investigated using aluminum adherends. The addition of fillers to the polymer matrix improved thermal stability and increased single-lap shear strength, indicating enhanced adhesive performance. The incorporation of TiO2 and Fe3O4 into poly(GMA-co-MMA) copolymer adhesive formulations yielded very similar maximum shear strengths, 421.03 and 420.15 N, respectively. The addition of HTU strongly increased the maximum shear strength to 1064.5 N. The highest value of 1884.12 N was obtained with the inclusion of HTB in the adhesive matrix, attributed to the polar interactions between HTB and the functional groups of the polymeric structure and the aluminum surface.