Modified Tannin Extracted from Black Wattle Tree as Environmental-Friendly Antifouling Pigment

The use of modified black wattle tannin as antifouling pigment is reported in this work. Mixture of tannin adsorbed in activated carbon (soluble fraction of tannin) and low soluble fraction of tannin was used as antifouling pigment. The soluble rosin resin was used as paint matrix. 13 C NMR analysis confirm the modification of black wattle tannin through the cleavage of tannin interflavonoid bonds. FTIR spectra indicates the presence of tannin in the formulated antifouling coating even after 7 months of its exposure in marine environment. Water contact angle analysis shows the hydrophilic characteristic of tannin antifouling coating surface. Immersion tests at Badalona port in Mediterranean Sea shows the high antifouling efficiency of TAN coating, comparable to the commercial paint, until 7 months. The use of a natural black wattle tannin, without its complexation with metals, can eliminate the release of metals and other toxic biocides to the marine environment.