Synthesis of PPG-TDI-BDO polyurethane and the influence of hard segment content on its structure and antifouling properties

Polyurethane have good anti-protein adsorption properties, could be used as an antifouling material. In this study, a type of polyurethane antifouling coating was prepared using 2,4-toluene diisocyanate and 1,4-butanediol as the hard segment and polyether polyols as the soft segment. The influence of hard segment content on the chemical structure, mechanical properties, and surface properties of the coatings was investigated. Subsequently, the antifouling performance of the polyurethane coatings was investigated by benthic diatom adhesion and panel tests. The results showed that coating H40 (polyurethane coating with a hard segment content of 40 wt.%) exhibited the best antifouling property. The antifouling performance of the coatings was further examined by evaluating the surface changes occurring in the polyurethane coatings during immersion in seawater. In situ diiodomethane contact angle measurements were performed to monitor such changes. The oil contact angle results were consistent with the results of the panel test. The oil contact angle and antifouling property are both determined by the surface roughness, which is determined by the level of microphase separation in the polyurethane coatings.