Eco-Friendly Sustainable Poly(benzoxazine-co-urethane) with Room-Temperature-Assisted Self-Healing Based on Supramolecular Interactions

ABSTRACT: This work is an attempt to develop bio-based eco�friendly poly(benzoxazine-co-urethane) [poly(U-co-CDL-aee)]
materials using cardanol-based benzoxazines (CDL) and hexam�ethylene diisocyanate (HMDI) to check their self-healing ability and thermal properties. CDL monomers were synthesized using cardanol, amino ethoxyethanol (aee) or 3-aminopropanol (3-ap), and paraformaldehyde through the Mannich reaction. Later, CDL�aee or CDL-3-ap monomers were copolymerized with a urethane precursor (HMDI), followed by ring-opening polymerization
through thermal curing. The thermal properties of poly(U-co�CDL) were evaluated by differential scanning calorimetry (DSC)
and thermogravimetric analysis (TGA). The self-healing behavior
of the bio-based poly(U-co-CDL) was checked by applying a mild
external pressure. The results revealed that the developed poly(U-co-CDL) showed repeatable self-healing ability due to
supramolecular hydrogen-bonding interactions. Further, the self-healing ability of poly(U-co-CDL) was studied using density
functional theory (DFT). From the above results, the developed material with superior self-healing ability can be used in the form of
self-healing coatings and composites for various applications with extended shelf-life and reliability