Role of Diisocyanate Structure on Self‐Healing and Anticorrosion Properties of Waterborne Polyurethane Coatings

Organic coatings are extensively investigated as possible solution to prevent or at least retard the occurring of corrosion processes on metal surfaces. Their actual breakthrough is still hampered by risk barrier properties loss because local failure coating integrity. To address this issue, self-healing coatings, which intrinsically able recover from damages upon exposure external stimuli, currently gaining increasing attention. Herein, waterborne polyurethanes (PU) synthesized, and a Diels–Alder adduct added into polymeric backbone endow material with functionality. The effect different diisocyanate in PU synthesis explored, namely isophorone diisocyanate, 4,4′-dicyclohexylmethane (HMDI), hexamethylene diisocyanate. obtained results highlight key role interactions among soft hard segments ultimately defining performances. Actually, combination Fourier transform infrared spectroscopy, atomic force microscopy X-ray diffration analysis reveals that HMDI-based have showed best balance terms H-bonding strength crystallinity degree ones. This allows reach good compromise mechanical resistance, anticorrosion properties, ability.