Chitosan as a Polyfunctional Crosslinker for a Renewable-Based Resorcinol Diglycidyl Ether
Iolanda Fusteș-Dămoc, Teodor Măluţan, Alice Mija
Abstract
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 °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 δ values ranging between 79 and 73 °C and storage moduli increasing with chitosan content ( E ′ ∼3.5–4.2 GPa), together with high crosslinking densities (15.65–27 mmol·cm –3 ).