Biobased, Biodegradable, Self-Healing Boronic Ester Vitrimers from Epoxidized Soybean Oil Acrylate

The global production of thermosets has been increasing in recent years causing rapid consumption of fossil-based feedstocks and contributing to the plastic waste accumulation in the environment, especially because they cannot be easily reprocessed or recycled at the end of their lifetime. These drawbacks can only be overcome with the development of environmentally friendly, recyclable thermosets from renewable resources. For this reason, we present a facile way to produce a biobased reprocessable thermoset, a vitrimer, by thiol-acrylate coupling between epoxidized soybean oil acrylate and a diboronic ester dithiol dynamic cross-linker. The synthesis of the cross-linker and all the processes for the production of the vitrimer has been done following green chemistry principles. The developed vitrimer material can be reprocessed multiple times like a thermoplastic, without compromising its mechanical properties. Moreover, it can be conveniently recycled by reversible hydrolysis in 90% ethanol and subsequent solvent evaporation, regenerating the original vitrimer. An important advantage of the developed material, especially regarding its applications, is that it is able to self-repair mechanical abrasion-related defects, like scratches and cuts, at room temperature, thanks to the low glass transition temperature and rapid boronic ester exchange, which enables it to demonstrate great potential as a self-healing coating. In case of an accidental release into the environment, it is able to biodegrade, solving the problem of waste accumulation.