Study On Waterborne Polyurethane Antifouling Coatings Modified By Fluoride And Siloxane DMU

At present, most antifouling coatings are solvent-based. In this paper, waterbome polyurethane antifouling coatings were prepared and characterized.Firstly, four series of waterborne polyurethane emulsion were prepared by designning components of soft segment and hard segment, modified with hydroxy siloxane and fluorined acrylate, respectively. The performance of emulsion and its film were characterized by FTIR, laser microscope, laser particle size analyzer as well as soaking in seawater. Then, antifouling coatings were prepared with nine groups of waterborne polyurethane emulsion while other compositions were the same. The surface properties, mechanical properties and seawater resistance of of antifouling coatings were characterized and analysed.The results showed:Higher level microphase separation was observed by laser microscope while the hard segment content increased. As the hard segment content of polyurethane increased, the antifouling coatings surface roughness increased, surface free energy became lower, friction coefficient decreasesd and water resistance was better. Waterbome polyurethane coatings modified by fluorined acrylate copolymer can improve the water resistance and mechanical properties, its water contact angle up to 104°. Waterborne polyurethane coatings modified with fluorined acrylate by core-shell emulsion method, its surface free energy drop to 5.32 mJ/m2. Special micron-sized pits were observed on the film of waterborne polyurethane modified with low levels of hydroxy siloxane. The water contact angle of its antifouling coatings reached 95°-100°.Optimized waterborne polyurethane antifouling coatings preparation method will be obtained by modifying with 0.38wt% fluorined acrylate copolymer.