Demanufacturing of thermoplastic composites: Small scale experiments exploring ply separation and recovery

• 12 mm wide PA6, PP and PBT tape plies were peeled apart under controlled conditions. • The PP and PBT tapes peeled readily at room temperature, PA6 did not. • The required peel force for PA6 tape ranged from 20 N at 192 °C to 0.26 N at 212 °C. • Failure mode and resulting surface character was dependent on peel temperature. • A potential window for PA6 peel without transverse failure is from 200 °C to 215 °C. Thermoplastic composites are intrinsically suited to recycling, but processes are poorly realised. Methods applied to thermosets are energy intensive, resulting in fibre downgrading and matrix loss. With digital manufacturing and data intertwining, the exact construction of a component can now be known. As such, instead of destructive recycling, a thermoplastic component might instead be demanufactured by peeling layers apart. In this study, the potential for recovering thermoplastic tapes by controlled peel was explored through novel small-scale tests. Unidirectional composites of three different tapes (PP/glass, PBT/glass and PA6/carbon) were compression moulded and subjected to transverse, lap shear and peel testing. Representative load and temperature conditions were established and their effects on the morphology of the recovered tape were considered. It was determined that peeling could be achieved well below the matrix melt temperature with only modest loading, and that contact failure changed from adhesive to cohesive at higher temperatures.