Recycled Poly(Ethylene Terephthalate) from Waste Textiles with Improved Thermal and Rheological Properties by Chain Extension

Annual production of textile fibers is continuing to rise and the substantial discharge of undegradable waste polyester fibers can cause serious environmental and even health problems. Thus, the recycling and reuse of recycled poly(ethylene terephthalate) from waste textiles (rPET-F) is highly desirable but still challenging. Here, five chain extenders with a different number of epoxy groups per molecules were used to blend with discarded PET fibers and improve its viscosity and quality loss in the recycling process. The molecule weight, thermal properties, rheological properties and macromolecular architecture of modified r-PET were investigated. It was found that all modified rPET-F samples show higher viscosities and better thermal properties. rPET-F modified by difunctional EXOP molecules show linear structure and improved rheological properties. rPET-F modified by polyfunctional commercial ADR and synthesized copolymers exhibit a long chain branched structure and better crystallization. This study reveals a deeper understanding of the chain extension and opens an avenue for the recycling of PET textiles.