Upcycling polyethylene terephthalate (PET) plastic waste into multifunctional aerogel-inspired materials

Upcycling polyethylene terephthalate (PET) plastic waste into multifunctional aerogel-inspired materials

Inspired by the lightweight and porous properties of aerogels and needle-punching nonwoven (NW) technology, this work successfully develops novel porous aerogel-inspired materials (AIMs) using recycled polyethylene terephthalate (rPET) fibers derived from PET plastic waste. These rPET AIMs can be continuously mass-produced at a productivity of 1.0 m/min, with an estimated production cost of 0.85 USD/m2 and without the use of toxic organic solvents typically employed in gel-based methods. rPET AIMs exhibit ultra-low density (0.030–0.114 g/cm3), high porosity (91.7–97.9 %), superior tensile Young’s modulus (0.08–69.60 MPa), and high decomposition temperature (350 °C). Particularly, with low thermal conductivity (32.3–35.5 mW/m·K) and excellent noise reduction coefficient (NRC) of 0.51, AIMs are highly competitive with reported freeze-dried PET aerogels and superior to other NW materials for effective heat and sound insulation. They also function as reusable oil sorbents, achieving the maximum oil uptake of 28.5 g/g, outperforming commercial oil sorbents such as polypropylene mats (15.0 g/g) and NW polypropylene sheets (9.0 g/g). When combined with carbon nanotube (CNT) to form a sandwich structure, the resulting rPET/CNT AIMs exhibit desirable properties for electromagnetic wave (EMW) absorption applications, including lightweight properties (0.133 g/cm3), flexibility, high thermal stability (350 °C), and excellent EMW absorption with over 90 % of EMW energy absorbed across nearly the entire X-band (8.2–12.4 GHz). With their cost-effective, eco-friendly production process and diverse high-value applications, recycled PET-based AIMs are highly promising for the construction industry as next-generation integrated heat-sound-EMW insulation materials for building walls, roofs, and glazing systems.