Co-cured carbon fibre/epoxy composite joints by advanced thermoplastic films with excellent structural integrity and thermal resistance
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Abstract
Carbon fibre/epoxy composite joints were assembled with Poly-etherether-ketone (PEEK) and Poly-ethylenimine (PEI) films using a co-curing process to prepare single-lap joint specimens. The joints were tested under quasi-static loading conditions at 22 °C and 130 °C and a fatigue loading condition. The experimental results demonstrated better or comparable structure integrity of the composite joints co-cured by PEEK and PEI films than the reference joints bonded by aerospace FM300 adhesives. In particular, the PEEK co-cured joints exhibited extraordinary mechanical performance at 130 °C and excellent fatigue resistance. For instance, the lap-shear strength at 130 °C and the fatigue life of the composite joints co-cured by 200μm PEEK films was 2.1 times and 2.7 times higher than that of the aerospace adhesive joints, respectively. Overall, the results of this work proved that advanced thermoplastic films are promising alternatives to epoxy adhesives for the co-cure joining of thermoset composites with significantly enhanced structural integrity and thermal stability.