UV-curable, oxetane-toughened epoxy-siloxane coatings for marine fouling-release coating applications

BACKGROUND: UV-curable coatings are promising candidates for environmentally friendly marine fouling-release coatings. Cationic UV-curable epoxy-siloxane release coatings show good release performance but suffer from poor coating mechanical properties. A difunctional oxetane monomer, DOX, was co-photopolymerized with an epoxy-siloxane oligomer at loading levels from 10 to 40 wt% to obtain toughened fouling-release coatings. RESULTS: The DOX-toughened coatings showed enhanced cationic photopolymerization activity, solvent resistance and modulus. DOX-toughened coatings (10 and 20 wt%) exhibited higher impact resistance. The DOX-toughened coatings showed no leachate toxicity and the coatings were hydrophobic and non-toxic to biofilm growth when analyzed with marine bacteria and algae. In general, 10 and 20 wt% DOX-toughencd coatings exhibited better marine bacteria and algae fouling-release performance among the DOX-toughened coatings. Pseudo-barnacle shear release stress for the DOX-toughened coatings increased with increasing DOX content. Live barnacle reattachment assay showed that 10 and 20 wt% DOX-toughened coatings had comparable barnacle removal stress to commercial silicone reference coatings. CONCLUSIONS: DOX-toughened (10 and 20 wt%) UV-curable epoxy-siloxane coatings exhibited enhanced mechanical properties and better overall marine fouling-release performance among the toughened UV-curable release coatings studied. (C) 2008 Society of Chemical Industry.