Antifouling activity of marine paints: Study of erosion

It is generally agreed that the prevention of marine fouling can be achieved by coatings from which a controlled release of toxic molecules prevents the growth of adhered organisms (bacteria, algae, molluscs). Since the end of 1990s, antifouling paints have been made by the blending of polyacrylic resins with biocides. The aim of this study was to use new polymers in order to obtain biodegradable antifouling paints with controlled release of biocide. Polyesters, such as poly(ɛ-caprolactone), PCL, poly(lactide), PLA, and their copolymers have received much interest in environmental applications because of their biodegradability. Polyanhydrides have also been considered as useful carriers of active molecules. Two families of biodegradable binders were studied: poly(phtalic acid- co-ricinoleic acid- co-isophtalic acid ester anhydride) (P(PA-RA-IPA)) and poly(ɛ-caprolactone- co-δ-valerolactone) (P(CL-VL)). Antifouling paints were formulated with these polymers and compared with commercial binders (PMMA-PBMA + rosin, and PMMA-TBT). Several methods have been used to investigate polymer erosion such as X-ray microanalysis (EDX), scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), nanoindentation, and FTIR spectroscopy. We have demonstrated that the polymers undergo predominantly surface erosion for poly(ester-anhydride) and PMMA-TBT and bulk erosion for polyester and PMMA-PBMA + rosin.