Influence of epoxy content on the properties and marine bacterial adhesion of epoxy modified silicone coatings

Abstract

This study addresses the issue of enhancing the mechanical properties and adhesion of silicone antifouling coatings. In this paper, γ-aminopropyltriethoxysilane was used to pretreat bisphenol A epoxy resin to obtain epoxy-silicone prepolymer, which was then mixed with hydroxyl-terminated polydimethylsiloxane to obtain epoxy-modified silicone. It was cured with polyamide curing agent and dibutyltin dilaurate catalyst to form film, and a three-component epoxy-modified silicone coating was prepared. Fourier transform infrared (FTIR) spectroscopy was used to characterize its chemical structure. The effects of epoxy content on the surface properties, mechanical properties and antibacterial properties of the coatings were characterized by confocal laser scanning microscope (CLSM), contact angle measurements, tensile test and bacterial adhesion test. The results show that adding epoxy makes the adhesion of the coating at level 1 and the surface free energy of the coating was between 15-21 mJ/m2. When its content is less than 22.1 wt %, the coating is in a ductile material state. Once it is higher than 22.1 wt %, the coating was in a brittle material state. As the content increases, material's hardness and fracture strength increases; elastic modulus decreases first and then increases, but bacteria removal rate decreases. The modification of the epoxy to silicone can effectively improve the adhesion and mechanical properties of the coating, while maintaining the characteristics of the low surface of the coating. It plays a positive role in improving the performance of silicone antifouling coatings.