Recoverable Polyanion Bead Catalysts for Selective Depolymerization and Fiber Recovery from Polyester Composites

Polyesters are widely used as composites in many commercial products, such as textiles, electronics, and automotive components, yet their multicomponent nature complicates separation processes and renders recycling impractical. Herein, glycolysis of polyester composites with macroporous polyanion bead catalysts selectively depolymerizes the polyester matrix, enabling facile recovery of the monomer product, non-polyester components, and the catalyst itself for reuse. Glass-fiber-reinforced PET and PBT are efficiently depolymerized, affording bis(2-Hydroxyethyl) terephthalate (BHET) yields of 95.8 ± 2.0% and 90.5 ± 2.6%, respectively. The non-corrosive nature of the glycolysis reaction condition preserves the glass fibers in both composition and length. Moreover, the macroscopic bead form of the catalyst allows simple filtration and density-based fractionation to cleanly separate reinforcing fibers and catalyst, and the recovered catalyst is reused over five cycles with an average BHET yield of 93.3 ± 4.3%. The polyanion bead-catalyst glycolysis extends to post-consumer polyester composites. Polyester/cotton textiles (65:35 wt%) give 98.9% depolymerization conversion and 93.7% monomer yield, with cotton morphology and chemistry preserved. Intact glass-fiber-reinforced polyester parts from automotive and electronics likewise yield both the polyester monomer and the reinforcing fibers. Scaling up further, a single ~40 g automobile polyester composites part affords 35.1 g of purified BHET and 10.8 g of clean glass fibers, showing that mechanically intractable composites can be recycled without grinding. Glycolysis with recoverable polyanion bead catalyst enables selective depolymerization of polyesters in composites, recovering catalyst, fiber, and monomer—turning unrecyclable composites into recoverable feedstock.