The development of recyclable crosslinked thermosetting fibres is a challenging research topic. In the present work, we have designed and synthesized polyurethane fibres from fructose-derived 5-chloromethylfurfural (CMF) and lignin-derived monomeric phenols. The greenhouse gas emissions associated with the production of CMF showed comparable results to that of 5-hydroxymethylfurfural (HMF), a high potential sugar-based platform molecule. The wet-spun biobased polyurethane fibres produced could be conveniently crosslinked using Diels–Alder chemistry to effectively enhance the glass transition temperature and mechanical properties. At a mildly elevated temperature (140 °C), the chemically crosslinked fibres could be effectively de-crosslinked, which enabled complete separation from a mixture with poly(ethylene terephthalate) (PET) and cotton fibres. These results outline a potential strategy to design and fabricate new biobased fibres with reversible crosslinking, which may enable fibre-to-fibre recycling. © 2024 The Authors. ChemSusChem published by Wiley-VCH GmbH.
The Swedish Foundation for Strategic Environmental ResearchMISTRA (Nos. 2016/1489 and F2019/1822) within the frameworkof the research program STEPS at Lund University. The SwedishResearch Council for Sustainable Development FORMAS (No.2021-01107). The Carl Trygger Foundation for Scientific Re-search (No. 18 : 435). The Crafoord Foundation (Nos. 20160774and 20180939). The Research Council of Norway through theproject L2BA – Lignin to BioAromatics (No. 321427).