| Anti-corrosive self-healing coating was successfully prepared by incorporating linseed oil based microcapsules into poly (urethane fatty amide) (PULFA?matrix. PULFA, a modified polyurethane, was prepared via a two-step synthetic routes, i.e. synthesis of N, N-bis(2-hydroxyethyl) fatty amide (HELA) from diethanol amine, linseed oil and sodium methoxide, followed by reacting HELA with tolylene-2,4-diisocyanate (TDI) under the nitrogen atmosphere. The structure of the purified intermediate HELA as well as the final polymer product PULFA was analyzed and verified by proton-NMR and FT-IR. The linseed oil microcapsule was prepared by a reverse emulsion technique studied and optimized previously in the group (L. Ware's thesis 2016). Purposive cracks on the coating surface were made to investigate the self-healing function by the standard salt testing method at various periods, while the quantitative corrosion property was further explored by electrochemical impedance spectroscopy. When the cracks were produced, microcapsules broke and released the healing agent linseed oil, which filled/healed the cracks by oxidizing with oxygen. In summary, 2% linseed oil microcapsule based PULFA coating has good anti-corrosion properties. |
