Preparation of PET-based aerogels from post-consumer packaging waste

In this work, a straightforward method to produce aerogels from recycled poly(ethylene terephthalate) (rPET) drinking water bottles is presented. It consists of dissolving the rPET, followed by precipitation and subsequent gelation, after which the aerogel is obtained by freeze-drying. Three types of rPET aerogels, unreinforced and reinforced with organic or inorganic fibers, were prepared using this method. The obtained aerogels have a porosity between 80 and 86% and a bulk density between 150 and 210 kg/m 3 . The resulting materials have good mechanical properties, with a Young's modulus between 1.5 and 3.5 MPa, and do not release particles when handled. They also show thermal insulation capability at the level of commercial thermal insulators (∼20–65 mW m −1 K −1 ). The observed presence of macropores in the predominantly mesoporous structure can be useful for sound absorption. The developed aerogels represent a unique opportunity to value plastic waste by producing an advanced material, following the principles of circular economy. • PET aerogels obtained only from waste through a dissolution/gelation method. • Monolithic aerogels with very low shrinkage, even without mechanical reinforcement. • Young's moduli of 1.5–3.5 MPa and temperature of 5% of degradation up to 393 °C. • Quartz fibers-reinforced aerogels show higher flexibility than non-reinforced ones. • Plastic waste as aerogel's raw-material reduces the cost and promotes circular economy.