Photo-Healable and Stretchable Fibers from Upcycled TPEE and Azopolymers by Harnessing Solid-to-Liquid Photoisomerization.

The increasing emphasis on environmental sustainability has driven the development of products derived from recycled plastics; however, their applications remain largely confined to packaging and beverage containers due to high recycling costs and limited economic viability. This study focuses on upcycling plastic waste by depolymerizing and repolymerizing waste polyethylene terephthalate (PET) into thermoplastic polyester elastomers (TPEE). To enhance the functional properties of the resulting material, an azobenzene-containing polymer (PAzo) is incorporated, leveraging its reversible photoinduced solid-to-liquid phase transition under ultraviolet and visible light irradiation. Electrospinning is employed to fabricate one-dimensional photoresponsive fibers composed of a TPEE/PAzo blend. The self-healing capability of the fibers is investigated by evaluating healing efficiency at different PAzo concentrations using tensile testing and analyzing microscopic healing behavior via scanning electron microscopy (SEM). This approach presents a potential strategy for developing high-value, recyclable, and smart-healing fibers.