Tensile Property and Toughening Mechanism of Nanoparticle-Modified Epoxy Adhesive

Abstract

Unmodified epoxy adhesive is a brittle material, which limits its application in practical engineering. Adding nanomodified materials to epoxy adhesives is an effective method to improve the tensile property. In this study, the composites were artificially dispersed for 10 min, and then dispersed for 2 h in an ultrasonic cell crusher to ensure the nanoparticles were evenly dispersed in the epoxy adhesive. The influence of SiO2 and TiO2 nanoparticles (NS and NT) with different mass fractions on the tensile properties of epoxy adhesives was analyzed, and the tensile section morphology of 11 kinds of the composites was observed by scanning electron microscope (SEM). In addition, the nanomodified epoxy adhesive model was simulated using software, which was based the Python language; randomly distributed nanoparticles were generated in the two-dimensional representative volume element (RVE) model. The experimental results showed that the tensile properties of epoxy adhesive increased first and then decreased with the increase of the mass fraction of nanoparticles. When NS or NT with a mass fraction of 0.05% or 0.40% were added to epoxy adhesive, the tensile properties of the composites reached their highest value. Through the SEM observation of the colloid tensile section, it was observed that the nanoparticles could change the composites’ fracture from brittle to ductile, which achieved the purposes of strengthening and toughening. The finite-element results showed that the difference between the simulated tensile properties and the experimental value of epoxy adhesive was within 5%, and thus the software model in this study has a certain reliability.