Comparing recycled and virgin poly (ethylene terephthalate) melt-spun fibres

Five different poly (ethylene terephthalate) (PET) materials (two recycled and three virgin ones) were melt-spun into fibres using a capillary rheometer and aerodynamic stretching. In order to cover a wide range of processing parameters, two temperatures in combination with six different take-up pressures were used during the melt spinning process. The surface smoothness, diameter and mechanical properties of the PET fibres were investigated. Compared with other studies, this study provides comprehensive research on melt-spun PET fibres. One recycled PET and one virgin PET in this study showed acceptable tenacity, outstanding elongation at break and desirable fibre fineness in denier. The molecular and rheological properties of these materials were studied further and presented minor differences in weight-average molar mass and molar mass distribution as well as in their viscosity, which resulted in their similar processing behaviour. This study proved the possibility to make a fibre from bottle-grade recycled co-polymer PET with similar properties to the fibre-grade virgin homo-polymer PET. •Two recycled and three virgin PET materials were investigated to be melt-spun into fibres.•A wide range of processing parameters was covered during the melt spinning process.•rPET-B and vPET-1 showed acceptable tenacity, outstanding elongation at break and a desirable fibre fineness.•It was possible to make a fibre from bottle-grade recycled co-polymer PET with similar properties to the fibre-grade virgin homo-polymer PET.•The similar mechanical properties of fibres were related to a higher crystallinity for vPET-1 but to a higher molecular orientation for rPET-B.