UV-curable Phthalazinone-containing Epoxy Methacrylate Coatings Using Capsaicin As Antifoulant

Developing new type of marine antifouling coatings to replace the traditional coatings is not only one of the focal points for the development of marine science, but also one of the important aspects for the protection of marine environment and marine organism. Most of the capsaicin type antifouling coatings that have been reported contain solvent, which lead to solvent volatilization during curing. This can't meet the demand of environmental protection, and can't reach long-acting aim because the effusion rate of capsaicin is unstable. Based on the existing problems, in this work, liquid epoxy acrylate resin were prepared then used as substrate. Finally, environment-friendly marine antifouling coatings were prepared by adding the synthesized capsaicin antifouling agent into the system. The properties of the coatings were studied and discussed.At first, liquid epoxy resin containing phthalazinone moieties was prepared by two-step reaction of 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one (DHPZ) and epichlorophydrin (ECH). The structure, solubility and epoxy value of the epoxy resin were characterized. The highest epoxy value reaches 0.38 mol/100g. Then the prepared epoxy resin was reacted with a-methacrylic acid to prepare epoxy (meth)acrylate resin (EMA) containing phthalazinone moieties . Orthogonal test with four factors and three levels was designed to study the effects of reaction parameters. The optimum reaction conditions are: catalyst amount is 2.2% (w/w); solvent content is 3.0:1 (w/w); acid dosage is 1.25:1 (mol/mol); temperature is 95°C.At preparing UV-curing coat, epoxy (meth) acrylate resin (EMA) containing phthalazinone was used as substrate, 2-hydroxyl-2-methyl-l-propiophenone (1173) was photoinitiator, 1,6-hexanediol diacrylate (HDDA) and trimethylolpropane tris-acrylate (TMPTA) were worked as reactive diluents. The optimum formula are as following: EMA: TMPTA: HDD=100: 30:10 (w/w/w); photoinitiator 1173 content is 3% (wt.%). The optimal mechanical properties of the coatings are: pencil hardness is 6H; adhesive force is firs-order; impact strength is 40 cm.Capsaicin, as a kind of non-toxic biological antifouling agent, was added to the UV curing coatings to prepare environment-friendly antifouling coatings. It is found that the coatings have good mechanical properties with pencil hardness of 5H and adhesive force of first-order when the capsaicin content is less than 10%. The antifouling capability was examined by two methods, of which one was measuring effusion rate of the antifouling agent and the other was locale experiment. Coatings of the test panel immersed in marine for 120d still have steady effusion rate. And the locale experiment shows that the test panels with 10% capsaicin, immersed for 120d are almost free of marine organisms and have good antifouling capability.