Recyclable, Fully Bio‐Based, High‐Performance Cellulose Long Filament Reinforced Vanillyl Alcohol Epoxy Composites for Structural Applications

Abstract The reusability of thermosets and their composites is challenging due to their robust crosslinked network structures, which underrate them as eco‐friendly materials and severely damage the ecosystem. Here, a novel biomass‐derived cellulose long filament (CLF)‐reinforced vanillyl alcohol epoxy (VAE) composite is fabricated that exhibited outstanding flexural strength of 232.2 ± 7.7 MPa and modulus of 26.9 ± 2.8 GPa compared to the previously reported bio‐mass derived composites. The green CLF‐VAE composite demonstrates good thermal stability and hydrophobic behavior due to the robust interaction between the hydroxyl (─OH) groups of CLFs and functional groups in the lignin‐derived VAE resin. Further, the chemical degradation behavior of the neat VAE thermoset and the green CLF‐VAE composite is studied in a nitric acid solution, and the recycled extract of the thermoset and its composite is used again for producing the 2^nd generation CLF‐VAE composite. The optimized 2.5 wt.% loading of the recycled extract in the 2^nd generation VAE thermoset and green CLF‐VAE composite demonstrated superior flexural strength and modulus compared to the 1^st generation thermoset and composite. The recyclability, along with good thermal and mechanical properties of the biomass‐derived green CLF‐VAE composite, shows its potential for high‐performance structural applications, merging sustainability with circular economy for green solutions.