A fully biomass based monomer from itaconic acid and eugenol to build degradable thermosets via thiol–ene click chemistry

Designing a fully biobased monomer to build a series of degradable thermosets is of great significance for sustainable development and environmental protection. In this work, a fully biomass based monomer (EUIT) was designed and synthesized from itaconic acid (IA) and eugenol (EU). Thiol–ene crosslinked polymers (TCPs) were prepared by changing the degree of the thiol functionality from 2 to 4 via a VOC-free thiol–ene click reaction. Also, the thermal, thermomechanical, and mechanical properties of these TCPs were investigated. The results showed that EUIT/4SH possessed the best comprehensive properties, that is, the glass-transition temperature (Tg) was up to 74.0 °C, and the mechanical properties including tensile strength and modulus were 58.6 MPa and 1.5 GPa, respectively, which were the maximum values compared with those in the reported investigations. Besides, these TCPs exhibited good degradable properties because of the inherent functional groups such as the ester groups in EUIT. Thus, this study provides a new method to prepare a fully biobased monomer and produce a series of degradable thermosets which are expected to be advanced biomedical materials, flexible electronic materials, etc.