Cyclic anhydride and epoxide ring-opening copolymerization is a versatile and controlled route to make polyesters, gaining attention in different application sectors but so far the chemical recycling of these polyesters to cyclic monomers is under-explored. Here, the catalytic chemical recycling of aliphatic polyesters to selectively form 16- and 18-membered lactones is presented. The recycling reactions are catalysed using commercial tin octoate and conducted in the polymer melt (230 °C) resulting in high conversions to the macro-lactones (>90%). The recycled macro-lactones undergo catalysed ring-opening polymerizations to produce polyesters with equivalent properties to the virgin materials.
Keywords:
Chemical Recycling * Depolymerization * Polyesters * Lactones * Catalysis
