Polymerized tung oil toughened urushiol-based benzoxazine copper polymer coatings with excellent antifouling performances

Marine antifouling is typically achieved by either antifoulant release or fouling release. An eco-friendly and economical new strategy is to combine the synergistic effects of both antifoulant release and fouling release to construct green marine antifouling coatings from natural products. Herein, a novel low surface energy coating was prepared by compounding natural polymerized tung oil (PTO) and urushiol-based benzoxazine copper polymers (UBCP). The introduction of PTO with long alkane segments significantly toughened the UBCP and reduced the modulus of the composite coatings (from 1258 MPa to 565 MPa), which weakened the adhesion of the fouling organisms to the surface and thus made it easier to remove. Moreover, a small concentration of copper ions in the UBCP was released from the composite coatings and had a synergistic antifouling effect. The antifouling performances of the composite coatings were tested with three different bacteria (E. coli, S. aureus and V. alginolyticus) and two microalgae (N. closterium and P. tricornutum), all of which were easily released from the composite coatings. This work develops a composite coating with synergistic effects of antifouling agents and fouling release as well as excellent antifouling performance using eco-friendly natural products as the main raw materials.