Experimental Validation of Hempoxies 20.1: A Hierarchical Carbon-Reinforced Bio-Vitrimer Composite System with Dynamic Covalent Networks

Bio-based epoxy resins are often limited by high melt viscosity ( η ∗ > 50 Pa·s at 25 ◦ C) and insufficient mechanical performance (tensile strength < 60 MPa), restricting their adoption in structural composites. This work proposes and experimentally validates Hempoxies 20, a fully bio-derived epoxy vitrimer based on epoxidized hempseed oil (EHSO), furfuryl glycidyl ether (FGE) as a reactive diluent, and a high-functionality succinic-anhydride-modified kraft lignin (Su-Lignin) as a multifunctional biobased hardener. Dynamic transesterification is catalyzed by zinc acetate. We hypothesize that the incorporation of FGE will reduce matrix viscosity to η ∗ < 10 Pa·s, enabling effective wetting and dispersion of hierarchical carbon powder reinforcement (milled carbonized hemp fibers, biochar, and exfoliated carbon nanosheets), while preserving crosslink density and vitrimer behavior. The resulting particulate composite is expected to achieve tensile strength σ t > 80 MPa, glass transition temperature T g > 100 ◦ C, topology freezing temperature 40 < T v < 80 ◦ C, and thermal self-healing efficiency η heal > 85%. This study constitutes a novel fully hemp-derived vitrimer composite system and establishes processing–structure–property relationships for recyclable, structural-grade biocomposites.