Antifouling Paints with Zinc “Tannate”

Abstract

During the past decade, the necessity of new ecofriendly antifouling pigments was established. Among these new pigments, special attention should be paid to tannin and its derivatives. Tannins are synthesized by plants as part of their defense mechanism against the attack of pathogens. The objective of this work was to study the antifouling efficiency of paints containing zinc "tannate" in artificial seawater. The zinc "tannate" was precipitated at pH 4 and pH 8. Insoluble and soluble matrix antifouling paints, with different plasticizers, were formulated and tannins leached from the paints immersed in artificial seawater were determined by the Folin-Denis assay for polyphenols. The antifouling action of paints was assessed in a natural seawater environment. The results showed that the leaching rate of tannin from insoluble matrix paint decreases, reaching a constant value after 25 days of immersion. In the case of the soluble matrix paints, a lesser amount of tannin was leached, depending on the tannin and the plasticizer employed. The results in a natural sea environment are dependent on the matrix and the plasticizer employed.

Antifouling and antibacterial activities of bioactive extracts from different organs of the sea cucumber Holothuria leucospilota

“…Consequently, because of the above-mentioned problems, International Maritime Organization banned the use of tributyltin since September 2008 [1,15]. Since the banning of tributyltin and other tin-based compounds, the tin is replaced by other metals like zinc [16], titanium and mostly copper [17,18]. Copper has good antifouling properties against some of the biofouling organisms like algae and barnacles [19], but copper can concentrate in shellfish tissues and has negative impacts on developing vertebrates and invertebrates [11,20].…”

Development of environmentally friendly antifouling paints using biodegradable polymer and lower toxic substances

“…So, an optimization of formulations and biocide release profiles is essential. For example, Bellotti et al have shown that antifouling paints with zinc "tannate" are promising, nevertheless, antifouling efficiency was dependent on the formulation: the matrix and the plasticizer employed modified the antifouling activity [19].…”

Marine-friendly antifouling coating based on the use of a fatty acid derivative as a pigment

“…At the present time, TBT and other tin-based antifouling agents are banned by the International Marine Organization (IMO) 15 . TBT-free formulations, in which tin is replaced by metals like copper 5,8,16 , zinc 17 and titanium 18 , are in use today. Although copper is essential for all forms of life due to cellular processes, it is considered toxic when tolerance limits are exceeded 19 .…”

“…The degree of fouling attachment was evaluated every month and distances less than 1.3 cm from the edge of samples were not considered 17,34 . The antifouling efficiency of the coating was carried out according to the fouling coverage area.…”