Green chemistry for the synthesis of methacrylate-based hydrogels crosslinked through Diels–Alder reaction

•Design of the dienic counterpart using furfural as renewable resource.•Green chemistry strategy involving all synthetic routes.•Aqueous Diels–Alder reaction for development of chemically cross-linked hydrogels.•Hydrogels obtained were pH sensitive with continuous porous microstructure and good storage modulus.

This study describes an environmentally friendly and green synthetic approach for the preparation of poly(aminoethylmethacrylate)-based hydrogels crosslinked through Diels–Alder (DA) reaction in water. This “click” reaction offers the possibility of preparing chemically crosslinked hydrogels in the absence of any catalyst, initiator or coupling agent, thus preserving the biocompatibility of the material. The suitable furan diene was obtained by modifying a methacrylate polymer by its reaction with furfural, a first generation compound derived from renewable resources. Methacrylate-based complementary polymeric dienophiles were also prepared by introducing maleimide groups into the structure. The products obtained at different steps were characterized by FTIR, NMR and TGA techniques. The study of the rheological properties of the hydrogels proved the success of this green “click” synthetic strategy confirming the formation of chemically crosslinked networks by the use of the Diels–Alder reaction. Furthermore, SEM studies revealed promising morphological properties of the ensuing hydrogels in terms of biomedical applications.

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