The growing demand for recycled PET in bottles is accelerating the search for solutions that combine circularity, performance and food safety.

The study by La Mantia and colleagues compares two strategies that are currently central to the industry: the use of blends of virgin and recycled PET, and the use of PET regenerated via solid-state polycondensation (SSP) – a treatment that increases the polymer’s molecular weight without melting it – evaluating them from a bottle-to-bottle perspective. The researchers compared recycled PET regenerated via SSP with PET subjected to successive cycles of mechanical recycling and with blends containing virgin and recycled PET to verify whether these solutions retain the characteristics required for the production of new bottles. Mechanical recycling leads to a progressive reduction in the viscosity and molecular weight of the material, with negative effects on the processability and final properties of the PET. PET regenerated via SSP, on the other hand, exhibits very different behaviour. The process restores the molecular weight to levels substantially equivalent to those of virgin PET, whilst improving the properties required for stretch-blow moulding processes. Tensile strength is also higher, with a marked increase in crystallinity.

According to the authors, blends offer an effective solution for increasing the recycled content in packaging, but regeneration via SSP offers additional benefits. Regenerated PET therefore emerges as the most comprehensive option for supporting high-performance bottle-to-bottle recycling systems.

Bibliografy: La Mantia F.P., Titone V., Botta L., Glerean P. Mechanical Recycling Processes of Polyethylene Terephthalate (PET) in the Framework of Circular Bottle-To-Bottle Manufacturing. Journal of Applied Polymer Science, 2026. https://onlinelibrary.wiley.com/doi/10.1002/app.57954