Despite extensive studies on the in-service performance of resistance-welded thermoplastic composites (TPCs), their potential for separation and re-welding in the context of sustainability, material recycling, repair or reuse remains underexplored. In this study, the disassembly and re-welding of carbon fibre-reinforced low-melting poly(aryl ether ketone) (CF/LM-PAEK) laminates joined by resistance welding is evaluated. Two resistance heating-based methods, partial and complete separation (PS and CS), are applied to separate the welded adherends from the heating element, which are subsequently re-welded using varying amounts of LM-PAEK in the weld zone. Both PS and CS yield clean separation surfaces without thermal damage. However, it is assumed that the PS is more error-prone when the temperature-controlled initiation of the separation process is not automated, CS is not feasible beyond a certain weld area. Mechanical lap-shear tests shows that welding after PS restores of the virgin joint strength, compared to for CS. Microscopy analyses indicate that strength losses could stem from matrix accumulation at the weld interface and squeeze-out of matrix from the weld zone during re-welding. These findings demonstrate that resistance-welded CF/LM-PAEK joints can be separated and reassembled with minimal losses regarding performance, thus offering a pathway towards closed-loop recycling of TPC structures.
Schafer et al. (Mon,) studied this question.