Depolymerized Poly(ethylene-2,5-furanoate) as a Sustainable Feedstock for Biobased Unsaturated Polyester Resins

This study describes the chemical upcycling of poly-(ethylene-2,5-furanoate) (PEF) waste into biobased thermosetting materials. High molar-mass PEF of intrinsic viscosity of 1.04 dL/g, serving as a model of postconsumer PEF, was synthesized by melt polymerization followed by solid-state polymerization. After characterization, PEF was depolymerized by glycolysis to give a mixture of hydroxy-terminated oligomers suitable as a raw material for the production of styrene-free unsaturated polyester resins. It was exemplified in a series of formulations that use biobased itaconic acid as a source of polyester unsaturation and biobased dimethyl itaconate as a reactive diluent. Mechanical and thermoanalytic testing of the cured formulations indicates that biobased materials produced in this way can serve as an equal substitute for fossil-based polyester resins currently used in the industry.