A tung oil-based epoxy resin modifier enhances flexibility and superhydrophobicity

The traditional epoxy resin (EP) is characterized by hydrophilicity and rigidity, and thus cannot be widely applied in special scenarios. Therefore, a siloxane grafted tung oil derivative was prepared as a multifunctional modifier based on the Diels-Alder reaction and added to the EP/ polyether amine curing system in different proportions. When the addition amount reaches 20 wt%, the flexibility of the material is significantly enhanced, the elongation at break reached 76.62 %. When nano-silica particles are sprayed onto the surface of the coating, a contact angle of 154.7 ° and a rolling angle of 4.6 ° can be achieved. The surface wettability test indicates that this coating has superhydrophobic properties. Additionally, the glass transition temperature (Tg) decreased from 67.25 °C to 41.84 °C. The temperature at mass loss of 5 % and 50 % were 327.7 °C and 395.2 °C respectively, indicating an improvement in the thermal degradation performance. After 800 h salt spray test, the modified coating can hardly see the corrosion marks, and has good corrosion resistance. The obtained results indicate that the sacrificial bond and six-membered ring structure in the tung oil-based modifier can enhance the toughness of the epoxy resin. Moreover, under the synergistic effect of siloxane and silica, superhydrophobicity can be achieved.