Jiuke Chen, Empa
Extruded PET (polyethylene terephthalate) fibres neat or with two different phosphorus PIN FRs (DOPO derivate DOPO-PEPA, phosphonate compound) were tested for mechanical recycling, with twin-screw extrusion – quench – spin-melt – reprocessing cycles (without ageing, total 3 extrusions). The neat PET showed little deterioration of properties with multiple extrusions. The phosphonate reacted with the PET during reprocessing causing cross-linking and brittleness. This, deterioration of the PET was mitigated by the DOPO derivate, which stabilised the recycled PET. A combination of these two PIN FRs showed compatibility with mechanical PET fibre recycling.