High strength lignocellulose derived epoxy adhesive with heat and acid-base resistance

In this work, we developed a high-performance two-component epoxy adhesive from two biobased triplefunctional and hexa-functional epoxy monomer from lignin-derived monomer eugenol, and a cellulose-derived furfuryl diamine for metal substrates. Through a tight cross-linked network and rich electronegative structure, the adhesives showed excellent adhesive performance to various metal substrates, especially for Fe. It demonstrated a high lap shear strength up to 19.8 MPa to Fe substrate, surpassing most reported epoxy adhesives. Moreover, these adhesives exhibited excellent long-term adhesion properties in high-temperature and acidic/ base aqueous environments. It can maintain more than 95% of the adhesive strength to Fe substrate after soaking in different acid-base environments for 7 days, and achieved a maximum adhesion strength of 16.46 MPa to Fe substrates at 200 degrees C only 14.2% decrease when compared to that at room temperature. Molecular simulations revealed that these two adhesives could rapidly achieve dynamic equilibrium with Fe (110) surface in 15 and 22 ps which was much shorter than that to Cu and Al, suggesting a stronger binding energy between these adhesive and Fe surfaces and was consistent with the adhesion performance. This work widens the way for highperformance bio-based epoxy adhesives to be used in more demanding environments.