A novel approach to design structural natural fiber composites from sustainable CO2-derived polyhydroxyurethane thermosets with outstanding properties and circular features
Guillem Seychal, Pierre Nickmilder, Vincent Lemaur, Connie Ocando, Bruno Grignard, Philippe Leclère, Christophe Detrembleur, Roberto Lazzaroni, Haritz Sardón, Nora Aranburu, Jean‐Marie Raquez
Abstract
We herein propose capitalizing on strong hydrogen bonding from novel bio-CO2-derived dynamic thermosets to achieve high-performance natural fiber composites (NFC) with circular features. CO2- and biomass-derived polyhydroxyurethane (PHU) thermosets were selected, for the first time of our knowledge, as matrices for their ability to make strong H-bond, resulting in outstanding mechanical properties for NFC. Exploiting this H-bond key feature, exceptional interface bonding between flax and PHU was confirmed by atomic force microscopy and rationalized by atomistic simulation. Without any treatment, an increase of 30% of stiffness and strength was unveiled compared to an epoxy benchmark, reaching 35 GPa and 440 MPa respectively. Related to the thermoreversible nature of hydroxyurethane moieties, cured flax-PHU were successfully self-welded and displayed promising properties, together with recyclability features. This opens advanced opportunities that cannot be reached with epoxy-based composites. Implementing CO2-derived thermosets in NFC could lead to more circular materials, critical for achieving sustainability goals.