Fast thermo-responsive thermoset self-healing polymers based on bio-derived Benzoxazine/Epoxidized castor oil copolymers for coating applications

This work emphasized on development of a novel bio-derived self-healing copolymer fabricated from benzoxazine and epoxy resins by varying weight ratios. The bio-derived benzoxazine (E-fa) acted as a healing agent was copolymerized with bio-derived epoxy resin namely epoxidized castor oil (ECO). Three main essential properties of the developed copolymer were systematically investigated: thermal property, mechanical property, and self-healing capacity. The numerical simulation was also used to study and predict the ability of roof coatings based on the developed copolymers. The results showed that the reversible crosslinking reaction occurred and resulted in state transition of the copolymers. The mechanical property i.e., tensile strength and peel strength to stainless steel substrate, were substantially improved with the incorporation of ECO. The increase in E-fa contents can enhance the thermos-responsive healing performance of the copolymers up to 93% via reversible reactions with rapid surface damage healed within 2 min. Furthermore, the experimental and numerical results revealed that the thermo-responsive thermoset self-healing bio-derived benzoxazine/epoxy copolymers have a potential use in coating applications required fast self-healing performance and good mechanical properties.