Fracture toughness of composite-to-composite joints of an elastomer-toughened ethyl cyanoacrylate adhesive for real-time aged batches and an accelerated aged adhesive batch

In this research, the mode I fracture energy of an elastomer-toughened ethyl cyanoacrylate adhesive was measured for composite-to-composite joints. The influence of weak acid concentration present in adhesive formulations on the fracture behaviour of the adhesive joints was investigated for real-time aged and accelerated aged adhesive batches. It was found that the adhesive weak acid concentration increased in both real-time and accelerated aged formulations and the polymerisation rate decreased. The fracture morphology and phase-separation of the elastomer was also determined by the adhesive weak acid concentration. Toughness was achieved at the expense of a slower curing rate. The effect of thermal treatment up to 110 °C on the phase separation of the elastomer in the adhesive joints was also investigated. After the thermal treatment, at higher weak acid concentrations, the mode of failure was cohesive with composite delamination. •Study of real-time and accelerated aged elastomer-toughened cyanoacrylate adhesive for composite-to-composite joints.•Rate of polymerisation is determined by the concentration of weak acid.•Elastomer phase-separation behaviour is determined by polymerisation rate.•Toughness was achieved at the expense of a slower curing rate.•At higher weak acid concentrations, the mode of failure of thermally treated composite joints, was cohesive with composite delamination.