Mechanical Properties, Thermal Stability, and Phase Structure of Polysulfone Toughened Epoxy Structural Adhesive

ABSTRACT Epoxy structural adhesives are widely used in various industries. However, it is still challenging to research the relationship between the mechanical properties and phase structure of toughened adhesives and their bonding properties. To address this issue, in this paper, an epoxy structural adhesive was fabricated using polysulfone (PSF) and dicyandiamide (DICY) as a toughener and a curing agent, respectively. PSF improved the toughness, thermal stability, mechanical properties, and bonding properties of the modified epoxy resin (EP). The tensile strength of the modified EP increased from 64.56 to 81.01 MPa when the PSF content increased from 0 to 60 phr. The impact strength of the 60 phr PSF modified EP increased by 319.0% to 61.55 kJ/m 2 , compared to that of the EP without PSF. For the 60 phr PSF modified EP, the tensile shear strength and peel strength between the aluminum alloy plate and aluminum honeycomb at room temperature were 45.98 MPa and 4.43 N/mm, respectively, which were 91.9% and 906.8% higher than those of pure EP. The improved performance of the modified EP system was attributed to PSF and the unique phase structure. The influence of the microphase structure on the bonding properties was explained by a combination of the microphase structure and mechanical properties of the modified EP.