Effects of release media on the fusion bonding of carbon/PEEK laminates

Carbon fibre reinforced thermoplastic composite laminates have been press-consolidated using various release media. The potential contamination of the laminate's surface by the release media and its effect on the performance of the joint after fusion bonding was studied. Before bonding, the physical and chemical state of the bonding surfaces were analysed by measurement the surface energy and roughness. The laminate surfaces chemical composition was investigated by X-ray photoelectron spectroscopy (XPS). Subsequently, the laminates were fusion bonded through an autoclave cycle. The mechanical performance of the joints was characterized by mode-I fracture toughness and short beam strength tests. The surface of some of the composite laminates were found to contain high concentration of the release medium residues after consolidation. This contamination showed a significant effect on the mechanical performance of fusion bonded joints. It was demonstrated that the performance of the joint can be regained by employing a simple cleaning method.