Chitosan as a Polyfunctional Crosslinker for a Renewable-Based Resorcinol Diglycidyl Ether

Chitosan is an abundant renewable biopolymer, insufficiently valorized, which is suitable for the development of sustainable and fully biobased materials. In this study, we combined it with the resorcinol diglycidyl ether, a biobased monoaromatic diepoxide. Formulations with a high chitosan content of up to 44 wt % were investigated and showed high reactivity and appropriate intervals of polymerization, ranging from 75 to 125 or 155 degrees C. The in situ Fourier transform infrared (FTIR) spectroscopy analysis confirmed that the two compounds reacted via an anionic polymerization mechanism combined with polyaddition reactions, proving that the chitosan acts as a polyfunctional crosslinker. The obtained thermoset resins have tan delta values ranging between 79 and 73 degrees C and storage moduli increasing with chitosan content (E ' similar to 3.5-4.2 GPa), together with high crosslinking densities (15.65-27 mmol center dot cm-3).

Automated summary

In this study, chitosan, an abundant biopolymer, was combined with a biobased monoaromatic diepoxide to develop sustainable and fully biobased materials. The obtained thermoset resins showed high reactivity, appropriate polymerization temperatures, and the presence of a polyfunctional crosslinker. The resulting resins had high crosslinking densities and storage moduli.