A novel amine-first strategy suitable for preparing both functional and engineering bio-polyamides: furfurylamine as the sole furan source for bisfuranic diamine/diacid monomers†

Biomass-based polyamides (bioPAs) are renewable materials that are viable alternatives to petroleum-based polyamides in the engineering field. However, limited attention has been paid to designing functional bioPAs with tunable properties. Herein, by taking furfurylamine as the sole furan source, we first utilized amine-acid oxidative conversion to prepare a bisfuranic diacid monomer directly from a bisfuranic diamine monomer (amine-first strategy), and it was totally different from the castor oil-based acid-first strategy for preparing PA1010. Then the as-prepared multifunctional diamine/diacid monomers underwent polycondensation to obtain all-furan-based bioPAs with or without functional pendant groups. The properties of bioPAs, including glass transition temperature, degradation character, solubility, etc., can be regulated over a larger range through the design of the spacer structure between two furan rings on diamine monomers. Charged bioPAs with cationic or anionic groups were further developed by postpolymerization modification. The oppositely charged bioPAs, sharing an identical main chain structure but different pendant groups, formed porous polyelectrolyte complexes owing to their rigid main chain. Therefore, this research provides a novel strategy for preparing both functional and engineering furan-based bioPAs.