A synchronously chemically closed-loop and high-performance approach for furan-based copolyesters with robustness, high gas barriers, and high puncture resistance

Utilizing bio-based resources is an essential part of the sustainable development of plastics. Meanwhile, the end-of-life options of bio-based plastics must be considered to avoid contributing to the accumulation of plastic waste. To address the problem of end-of-life plastics and the trade-off between chemical closed-loop recycling and high performance, targeted selection of monomers and a method for the preparation of high-performance linear polyesters that can be rapidly closed-loop recycled without the addition of additional organic solvents under mild conditions are necessary. Herein, we report strategies for synchronously constructing chemical closed-loop polyesters and achieving high performance, by using linear furan-based poly(butylene furandicarboxylate-diethylene glycol) (PBDyF), synthesized from dimethyl 2,5-furandicarboxylate, diethylene glycol (DEG) and 1,4-butanediol (BDO). Adjusting the ratio of ethyleneoxyethylene and butylene groups can endow PBDyF with excellent tensile strength (77.8 MPa), puncture resistance properties (129.7 N mm(-1)), and barrier properties (CO2 0.0120 barrier and O-2 0.0103 barrier) for PBD80F. Processing can be performed by injection moulding, and additive manufacturing, such as 3D printing. Moreover, we developed a rapid chemical-solvolysis strategy under mild conditions without producing other organic waste by using DEG/BDO to obtain recycled 2,5-furandicarboxylate, DEG, and BDO from PBDyF. Utilizing the differences in the solubility and boiling point, the recycled chemicals can be separated. The repolymerized polyester (rPBD(y)F) still maintains high performance compared with PBDyF. In our approach, the high-performance chemically recyclable copolyester, exhibiting greatly potential films or 3D printing applications, provides a state-of-the-art method for solving the trade-off problem between the chemical-recycling and high performance of previous linear polyesters, further supporting sustainable closed-loop chemistry.

Automated summary

This article introduces a strategy for simultaneously constructing chemically closed-loop polyesters and achieving high performance by synthesizing linear furan-based polyesters PBDyF. A rapid chemical-solvolysis strategy is developed to obtain recyclable chemicals from PBDyF. PBDyF exhibits excellent mechanical properties and barrier properties, and can be processed by injection molding and 3D printing.