Improved Processes for Joining of Polyetheretherketone (PEEK) Thermoplastic Components

A new chemical surface treatment is proposed that will prepare the surface of polyetheretherketone (PEEK) components for traditional structural adhesive bonding. This low viscosity treatment is easily applied to the adherend in an ultra-thin layer, cures quickly, and is adaptable to a field repair scenario. In-house studies of this material resulted in cohesive failure of a lap shear bond between PEEK/carbon composite test coupons. This data supports the observation that the adhesive bond of the surface treatment to the PEEK/carbon composite surpasses the strength of the adhesive. The surface treatment is free of volatile organic compounds (VOCs) and will be an environmentally-friendly alternative to other more aggressive surface treatments such as chromic acid etching. The Phase I effort will be devoted to progressing the development of this surface treatment and testing its ability to bond IM7/APC-2 composite material. Mechanical testing will include wedge test adhesion analysis, lap shear adhesion testing, and environmental durability analysis using standard adhesion test methods such as ASTM D1002. TRI/Austin will be teaming with a leading aircraft repair training facility during the Phase I effort in order to utilize their expertise of the necessary requirements for Air Force field repair.