Self-healing polymers based on eugenol via combination of thiol-ene and thiol oxidation reactions

Eugenol, a relatively cheap and abundant renewable resource, is used to design terminal diene compounds. Thiol-ene click reactions between the terminal diene intermediates and 1,6-hexanedithiol afford the corresponding oligomers with molecular mass of about 1.3 kDa. Finally, the oligomers and tricapto compound trimethylolpropane tris(3-mercaptopropionate) undergo thiol-oxidation reactions to form disulfide-crosslinked polymers. The brown polymers indicate self-healable behavior under UV light irradiation, presumably due to reversible reshuffling of weak disulfide bonds and/or reversible addition-dissociation reaction between benzoxazine and thiol groups.