Work-hardening Photopolymer from Renewable Photoactive 3,3’-(2,5-Furandiyl)bisacrylic Acid

• Published in: ChemSusChem
• Main Authors: Lie, Yann, Pellis, Alessandro, Funes-Ardoiz, Ignacio, Sampedro, Diego, Macquarrie, Duncan J., Farmer, Thomas J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: Antarc*; Antarctica
• Online Access: https://eprints.whiterose.ac.uk/164306/; https://eprints.whiterose.ac.uk/164306/1/cssc.202000842.pdf; https://doi.org/10.1002/cssc.202000842

The design of a photopolymer around a renewable furan-derived chromophore is presented herein. An optimised semi-continuous oxidation method using MnO2 affords 2,5-diformylfuran from 5-(hydroxymethyl)furfural in gram quantities, allowing the subsequent synthesis of 3,3’-(2,5-furandiyl)bisacrylic acid in good yield and excellent stereoselectivity. The photoactivity of the diester of this monomer is confirmed by reaction under UV irradiation, and the proposed [2+2] cycloaddition mechanism supported further by TD-DFT calculations. Oligoesters of the photoreactive furan diacid with various aliphatic diols are prepared via chemo- and enzyme-catalysed polycondensation. The latter enzyme-catalysed (Candida antarctica lipase B) method results in the highest Mn (3.6 kDa), suggesting milder conditions employed with this protocol minimised unwanted side reactions, including untimely [2+2] cycloadditions, whilst preserving the monomer's photoactivity and stereoisomerism. The photoreactive polyester is solvent cast into a film where subsequent initiator-free UV curing leads to an impressive increase in the material stiffness, with work-hardening characteristics observed during tensile strength testing.