New approach to surface preparation for adhesive bonding of aeronautical composites: atmospheric pressure plasma. Studies on the pretreatment lifetime and durability of the bondline

In two previous studies, promising results regarding the feasibility of atmospheric pressure plasma (APP) as surface preparation for aeronautical composites prior to structural assembly by adhesive bonding were presented. In this paper, further investigations to assess the viability of this pretreatment technique were performed. Thus, APP treatment effects upon both the lifetime of the pretreatment and the long-term durability of composite adhesive bonds were demonstrated by contact angle measurements, surface free energy by using both Owens-Wendt-Rabel-Kaeble and test inks analyses and single lap shear tests. As a result, the effective combination of removal of release compounds, chemical activation and new topographical features were correlated with excellent long-term adhesion properties.