PRELIMINARY RESULTS OF THREE NATURAL EXTRACTS FOR ANTIFOULING PAINTS

GARCIA, M.; PÉREZ, M.; SÁNCHEZ, M.; BLUSTEIN, G.; PALERMO, J.A.; STUPAK, M.

Seattle

Congreso; 16th International Congress on Marine Corrosion and Fouling; 2012

COMITÉ INTERNATIONAL PERMANENT PUR LA RECHERCHE SU LA PRÉSERVATION DES MATÉRIAUX EN MILIEU MARIN (COIPM)

Natural extracts with potential activity were used in antifouling soluble matrix paints: an ethanolic extract of the marine sponge Clathria microxa and two polar subextracts of the plants: Hyalis argentea and Nardophyllum bryoides. The plant extracts were selected on the basis of their chemical diversity while the sponge extract was chosen for the empirical observation of the absence of fouling on the organism´s surface and the presence of complex secondary metabolites. For the preparation of the soluble matrix antifouling paint, colophony (resin) and oleic acid (plasticizer) were dissolved in a xylene/white spirit (1:1 % by weight) mixture using a high-speed disperser. Then, a laboratory scale ball mill was loaded with the vehicle followed by zinc oxide and calcium carbonate which were dispersed for 24 h. The extracts (0.8% v/v) were incorporated to the paint and then, dispersed during 1 h. Sandblasted acrylic tiles (4 cm×12 cm) were used for field trials. Paints were applied by brush on tiles previously degreased with toluene. Three coats of paint were applied and allowed to dry for 24 h between each application, resulting in a final dry thickness of 150±5_m. Panels were hung in a marina in Mar del Plata harbor to a depth of 50 cm below the water line. In addition, two controls were used, one of them was unpainted acrylic tiles and the second one, tiles treated with paint without extracts. After one month exposure in the sea, natural products-based paints were effective in inhibiting settlement. A great decrease in micro and macro-fouling density and diversity was observed in relation to controls (p