Study on synthesizing new urethane epoxy adhesives and their adhesive properties on different substrates

Abstract

In this work, we prepared urethane epoxy adhesives from the reaction of glycidol and aliphatic diisocyanate, 4, 4-methylene bis (cyclohexyl isocyanate) (HMDI). We modified diglycidyl ether of bisphenol A (DGEBA) with this urethane epoxy and cured by maleic anhydride. We used Fourier-transform infrared (FTIR) for monitoring the reaction progress and confirming the unique structure. We measured the lap shear strength of joints, bonded with different weight ratios of urethane epoxy and DGEBA, on three different substrates aluminum, stainless steel, and glass fiber reinforced epoxy. The effect of substrates with varied materials was studied by scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX) with comparisons with X-ray photoelectron spectroscopy (XPS) results from other studies. The novel urethane-epoxy adhesive exhibited improvements in mechanical properties such as shear strength and elongation in comparison to common DGEBAbased epoxy adhesives.