How Poly(Ethylene Terephthalate) (PET) From Mechanically and Chemically Recycling Affects the Performance of Monopolymer Blends

From 2030, in line with the new directive issued by the European Union, manufacturers of plastic beverage bottles will have to include at least 30% recycled plastic, calculated as an average for all bottles placed on the market in each Member State. In this context, many companies and start‐ups are producing blends of virgin poly(ethylene terephthalate) with mechanically or chemically recycled poly(ethylene terephthalate). In this study, a monopolymer blend composed of virgin poly(ethylene terephthalate) and 30% mechanically recycled poly(ethylene terephthalate) was prepared and compared with a commercial blend containing 30% chemically recycled poly(ethylene terephthalate). Rheological (processability) and mechanical properties were evaluated. The results show that the monopolymer blend with 30% mechanically recycled poly(ethylene terephthalate) exhibits mechanical properties similar to the commercial blend, with percentage variations of approximately +10.9% for elastic modulus, +5.8% for tensile strength, and −13.6% for elongation at break. Furthermore, when reprocessed, the properties remain largely preserved. An additive model accurately predicts blend behavior, with deviations between experimental and theoretical values generally below 10%.