Dynamic simulations of a self-polishing antifouling paint exposed to seawater

A mathematical model for a self-polishing antifouling paint exposed to seawater was extended to handle dynamic simulations. The aim has been to investigate, quantitatively, the transient responses of the paint to changes in seawater temperature, pH, concentration of NaCl, and ship speed. The simulation study revealed that polishing and biocide release rates for a paint present on a ship bottom rarely reach stable conditions, because of the slow response of the paint to changes in temperature and ship speed. It was also found that the paint behavior stabilizes more rapidly from a temperature or speed increase than from temperature or speed reductions. These results are essential for the testing of paints on ships and useful information in the development of novel self-polishing antifouling paints. The modeling approach underlying the simulations can be applied to any type of self-polishing antifouling paint provided that sufficient kinetic, solubility, and diffusivity data are available for the pertinent rate steps influencing the paint behavior. Dept. of Chemical Engineering, Building 229, DK-2800 Kgs. Lyngby, Denmark. Lundtoftevej 150, DK-2800 Kgs. Lyngby, Denmark. P.O. Box 808213 Polinyà, Spain.     

RP-HPLC optimization of econea by using artificial neural networks and its antifouling performance on the Turkish coastline

Coverage of artificial surfaces within seawater by fouling organisms is defined as biofouling. Although biofouling is a natural process, it has some disadvantages for shipping industry such as increased fuel consumption, and CO₂ emission. Therefore, the ships' hull must be covered by antifouling (AF) or fouling release type coatings to overcome biofouling. In general, the so-called self-polishing AF paints contain biocides for preventing fouling organisms. Their concentrations and release rates from AF coatings are of great importance and they definitely affect both quality and cost of the coating. In the present study, we aimed at applying a new robust method. In this method, we used a model biocide, i.e., econea, to obtain its RP-HPLC optimization through artificial neural networks (ANN) and to see its antifouling performance. Column temperature, mobile phase ratio, flow rate, concentration and wavelength as input parameters and retention time as an output parameter were used in the ANN modeling. In conclusion, the R&D groups in AF paint industry may use RP-HPLC method supported with ANN modeling in further studies.     

自抛光防污涂层及评价技术的发展

介绍了自抛光防污涂料的防污机理和防污特点,概括了有机锡自抛光防污涂料和无锡自抛光涂料的防污机理和发展状况,阐述了几种不同无锡自抛光涂料的防污原理,对自抛光防污涂料通过测定防污涂层的有效成分渗出率间接反映防污性能的评价方法和实海挂板直接评价防污涂层的防污性能的传统评价方法进行了总结。详细介绍了几种自抛光防污涂料室内动态模拟性能评价方法和生物性能评价方法,并对自抛光防污涂料的发展方向进行了展望。     

Surface-fragmenting, self-polishing, tin-free antifouling coatings

Surface-fragmenting types of self-polishing tinfree resins were characterized by IR and NMR and demonstrated the successful synthesis of cupric carboxylate. According to the IR,¹H-NMR and¹³C-NMR measurements, it is clear that the unsaturated double bonds present in the resins changed into other new bonds after drying in a manner similar to alkyd resins. These resins were used as binders to prepare antifouling paints. Scanning electron microscopy (SEM), rotary tests, raft tests, and ship tests were used to investigate the self-polishing phenomena and the antifouling ability of this type of antifouling paint. The SEM photographs obtained from the paint surfaces demonstrate self-polishing phenomena. From the rotary tests, the polishing rates of paints were measured as 10μ ∼ 5.7 μ/month. The results from the raft tests show that all of the paints exhibit excellent antifouling ability and are about 80 ∼ 90% as effective as the conventional tin-containing antifouling paints. Dept. of Chemical Engineering, Tainan, Taiwan, R.O.C. #26 Yen Hai 3rd Rd., Kaohsiung, Taiwan, R.O.C.     

GLOBIC--低阻抗防污技术

通过试验和实船测量，证明了新型无锡自抛光防污漆GLOBIC系列的自磨平性和低阻抗性，并给出不同系列防污漆的使用寿命。     

生物降解型无铜防污涂料研究

讨论了目前主流自抛光防污涂料存在的环保性问题,介绍了生物降解型防污涂料最新的研究进展情况。指出生物降解型涂料成为环保型自抛光防污涂料的重要研究方向。报道了生物降解型生态友好防污涂料研究的一些初步进展。介绍了基于聚乳酸的含嵌段结构的生物可降解防污涂料用树脂以及生物降解型无铜防污涂料最新的某些研究进展情况。     

新型无毒防污涂料

综述了近几年来开发出的几种新型防污涂料的情况,从防污机理出发,重点介绍了低表面能防污涂料、仿生涂料、无锡自抛光防污涂料等,并对无毒防污涂料今后的发展进行了展望。     

Effects of marine microbial biofilms on the biocide release rate from antifouling paints—A model-based analysis

The antifouling (AF) paint model of Kiil et al. [S. Kiil, C.E. Weinell, M.S. Pedersen, K. Dam-Johansen, Analysis of self-polishing antifouling paints using rotary experiments and mathematical modelling, Ind. Eng. Chem. Res. 40 (2001) 3906–3920] and the simplified biofilm growth model of Gujer and Wanner [W. Gujer, O. Wanner, Modeling mixed population biofilms, in: W.G. Characklis, K.C. Marshall (Eds.), Biofilms, Wiley–Interscience, New York, 1990] are used to provide a reaction engineering-based insight to the effects of marine microbial slimes on biocide leaching and, to a minor extent, polishing behaviour of AF paints. It is concluded that the perturbation of the local sea water conditions (e.g. pH), as a consequence of the metabolic activity of the biofilm should not affect the net biocide leaching and binder reaction rates significantly. This results from the thin and poorly active biofilms which presumably grow onto the highly effective modern AF paints. According to simulations, the experimental decrease in the biocide leaching rate caused by biofilm growth must be mainly attributed to adsorption of the biocide by the exopolymeric substances secreted by the microorganisms. The effects of biofilms on the leaching of any generic active compound (e.g. natural antifoulants) are discussed in relation to their potential release mechanisms. The largest influence of biofilms is predicted for those active compounds that are released by a diffusion-controlled mechanism (typically tin-free algaecides).     

Cupric tannate: A low copper content antifouling pigment

Fouling organisms attached to man-made surfaces submerged in seawater constitute a major worldwide technical and economical problem. Protection against biofouling is essential for efficient service of boats and ships. Due to recent and imminent restrictions of the use of traditional toxic antifouling paints, there is a growing need for new alternative compounds that ensure a good performance without polluting the marine ecosystem.

The aim of this work is to develop a new antifouling formulation using compounds of natural origin, i.e. tannates, in combination with a minimum concentration of a known bioactive pigment, i.e. copper.

Laboratory assays have shown that cupric tannate has a narcotic effect on biofouling larvae. In the field, after 12 months of immersion in Mar del Plata harbor (Argentine), none of the tested painted panels showed macrofouling organisms. This result was obtained with a large decrease in copper content in the order of 40 times relative to conventional cuprous oxide based paints.

Because copper tannate is not lethal at low concentrations, this pigment has an excellent potential as an antifouling agent.     

Biofouling Growth in Cold Estuarine Waters and Evaluation of Some Chitosan and Copper Anti-Fouling Paints

Ecological concerns about antifouling paints containing non-green tin and copper compounds have highlighted the need for environmentally friendly alternatives. We report here a field test conducted in estuarine waters over two months designed to evaluate the efficiency of a number of active natural and man-made chemical ingredients added into a silicon-polyurethane marine paint. Early steps of biofouling in cold seawater of the St. Lawrence Estuary (Canada) were observed. Analyses, including dry biomass, flow cytometry and spectrofluorimetry, demonstrated a short-term antibacterial action of chitosan-based paints although no significant anti-algal action was observed. Cuprous oxide paints were efficient against bacteria and algae invasion in the first two weeks, especially those with added organic biocides such as isothiazolone and copper pyrithione. However, the overall dry biomass and chlorophyll a content were similar for all chitosan-and copper-based paints after 63 days. Microscopic observations revealed variation in the highly diverse benthic diatom population including species Navicula, Melosira, Cocconeis, Nitshzcia, Fragilaria and Amphora. Results suggest no real long-term efficiency for tested antifouling paints and highlight a particular need for green antifouling ingredients that are active under northern estuarine conditions.     

防污涂料中氧化亚铜的渗出速率及降解行为研究

氧化亚铜(Cu2O)作为在目前海洋防污涂料广泛使用的防污剂,研究其渗出速率和在海洋环境中的降解行为具有重要的意义。介绍了ISO15181铜离子渗出速率测试方法,并研究了不同配方的自抛光型防污涂料的铜离子渗出速率,最后研究了氧化亚铜在海洋环境中的降解行为。结果表明:铜离子渗出速率可通过涂料配方进行调整,氧化亚铜在海洋环境中的最终降解产物是碱式碳酸铜。     

Development of hybrid antifouling paints

The objectives of this study are to measure the efficiency of a hybrid system for antifouling paint and to observe the influence of the physico-chemical properties of the binder on the antifouling activity. Poly(ɛ-caprolactone) (PCL) and poly(dimethylsiloxane) (PDMS) homopolymers are already used as binder for different antifouling strategies. The use of the block copolymer should allow to mix the properties of erosion and hydrophobicity to obtain a more efficient paint with a reduced environmental impact.Paints containing triblock copolymer were immersed in seawater in Lorient harbour to evaluate their antifouling activities. The water absorption, the degradation and the surface properties of the copolymer were measured in distilled water to understand the influence of the binder characteristics in the resulting antifouling properties.The hybrid paints have shown efficiency close to a commercial paint during their immersion in situ in spite of inadequate static conditions of test.     

舰船防污涂料的历史、现状及未来

舰船防污涂料的发展分为三个阶段,即传统的常规防污漆、现代有机锡共聚物自抛光防污漆和无锡自抛光及无毒防污涂料。我国目前处于第二阶段的初期水平。作者通过回顾历史、分析现状,对今后舰船防污涂料的发展作了展望。     

藤壶剪切强度试验及探讨

简便有效的测试评价方法可以缩短防污漆的开发周期,为其实际应用提供可靠依据。评价低表面能防污漆的测试方法主要有动态模拟试验、藤壶剪切强度试验、涂层降阻试验等。本文以ASTM D5618—1994(2011)为参照进行低表面能防污漆和自抛光防污漆的浅海浸泡对比试验,测算藤壶剪切强度,通过对比试验探讨其防污性能等;通过推演的公式可用于估算剥离藤壶的水流剪切相对速率及航速,完善试验方法,使其更具实际应用意义和参考价值。     

新型有机硅自洁耐沾污机理的研究

以有机硅树脂低聚物为主要成分制备的耐沾污剂，不仅具有优异的自洁耐沾污性能，而且固化迅速。用FTIR、GPC等分析仪器对有机硅低聚物的结构与性能进行了表征测试，并通过SEM、接触角测量仪等对影响有机硅防污剂的耐沾污因素及机理进行了研究。     

Anti-fouling paints. I. Theoretical approach to leaching of soluble pigments from insoluble paint vehicles

A theoretical approach to the problem of how contact leaching anti-fouling paints work is discussed; a possible mechanism is selected and applied to an idealised model of a paint film. A precise mathematical treatment is then attempted of the relationship between the leaching rate, the physical properties, and if applicable the chemical properties of the envisaged paint film and its environment. A mechanism previously proposed has been examined by this method. An equation is derived for an idealised paint film relating the leaching rate to the physical properties of the paint film and the leachate. It is assumed that the rate of solution of a soluble pigment from an insoluble vehicle is dependent only on the physical properties of the paint film and the diffusion of the solvated pigment through the exhausted matrix and the diffusion layer of leachate in direct contact with the surface of the paint. An equation is derived for an idealised paint film which relates the leaching rate to some physical properties of the paint film and of the leachate. The equation is shown to predict qualitatively the effect of most variables known to affect the leaching of contact leaching paints. Some evidence is given to support the quantitative prediction of the relationship between the pigment volume content and the initial leaching rate, the effect of dissolved pigment in solution on the leaching rate, the increase in leaching rate for a given temperature increase, and the effect of velocity of flow past the surface of the paint film. This method of approach would appear to be applicable to mechanisms and models bearing a closer resemblance to practical anti-fouling paints. However, the mechanism proposed appears sufficiently well substantiated to be employed in the design of leaching experiments and their application to more practical problems, such as the formulation of anti-fouling paints. The need of a more rigorous approach to the design of leaching experiments is indicated.     

Dissolution rate measurements of sea water soluble pigments for antifouling paints: ZnO

The dissolution of soluble pigments from both tin-based and tin-free chemically active antifouling (AF) paints is a key process influencing their polishing and biocide leaching rates. In this context, a low time- and resources-consuming method capable of screening the pigment behaviour in the search for the most promising materials or mixtures is of great interest. A preliminary attempt to develop such a method is presented in this paper based on the widely used ZnO pigments.

While highly pure, nano-polished, monocrystalline ZnO substrates yielded very low dissolution rates in the order of 17.3 ± 3.7 μg Zn²⁺ cm⁻² day⁻¹, pellets prepared by compacting and sintering technical grade ZnO pigments dissolved about three times faster according to inductively-coupled plasma mass spectrometry (ICP-MS) measurements. The rougher and more porous surface exposed, together with the larger number of defects in the lattice structure, are hypothesised to be responsible for the faster sea water attack of the pellets compared to the ZnO crystals. In any case, the ZnO dissolution rates reported in this paper are markedly lower than those associated with the sea water dissolution of cuprous oxide (Cu₂O) particles which are also used in AF paints. Experimental performance testing of model antifouling paints formulated with ZnO and/or Cu₂O demonstrates that the binder/pigment interaction should not be disregarded if the leaching of sea water soluble pigments from paint systems is to be determined.     

High-build soluble matrix antifouling paints based on vinyl resin

The aim of this work was to formulate and evaluate high-build, soluble matrix antifouling paints showing reduced solvent retention in the film and sufficient bioactivity to protect structures submerged in sea water for long immersion periods.

The variables analyzed were binder composition, pigment content, toxicant type and thixotropic agent content.

Binder dissolution in sea water was achieved by employing WW rosin or calcium resinate; the control of the binder dissolution rate was achieved by using a vinyl resin as a cobinder. The paints were formulated with pigment volume concentrations of 40 and 45%; red cuprous oxide and triphenyl tin fluoride were used as the main toxicants. The rheological additive employed was hydrogenated castor oil at levels of 2.0 and 2.5 wt.% in the paint.

The bioactivity of the antifouling paints was determined in the natural environment (30 month immersion in sea water).     

Prevention of biofouling on aquaculture nets with eco‐friendly antifouling paint formulation

Aquaculture, which is an important part of food supply, is usually carried out in cage nets made of textile materials. Fouling organisms settle on the cage nets over time, close the mesh openings, and cause unwanted weight gain. In order to prevent fouling, aquaculture nets are generally treated with antifouling paints. In this paper, warp knitted cage nets made from various raw materials were treated with three different antifouling paints. Econea was used as a biocide to prepare an eco‐friendly antifouling paint formulation, and two copper‐based commercial antifouling paints were supplied for comparison. Antifouling paint‐treated and untreated net samples were immersed in a marine ecosystem next to an aquaculture zone for 6 months. Settlement of fouling organisms on nets was observed by taking underwater photographs at periodic intervals. Following the field study, changes in the structure of the nets and antifouling performance of the paints were evaluated considering the results of underwater photographs, biomass growth, variation in mass and strength tests. Colour fastness of the antifouling paints to sea water was also measured to learn about biocide release and surface hydrophobicity. The results show that copper‐free eco‐friendly antifouling paint is just as effective against the fouling mechanism for all types of nets as copper‐based commercial antifouling paints. The novel eco‐friendly formulation has promising results, which provides an alternative for producers when considering the selection of raw materials.     

海洋防污涂料技术的研究现状及展望

叙述了海洋防污涂料类型与研究现状,介绍了新型环保的低表面能防污涂层技术在海洋方面的应用,介绍了异噻啉酮衍生物（MOP-OCI）对藻类生长的抑制作用,以此化合物为防污剂制备的海洋防污涂料,5个月的实海挂板几乎没有附着海洋污损生物。重点介绍了有机硅涂料、有机氟涂层以及绿色防污涂料的国内外研究进展和应用现状,并介绍了几种防污涂料的防污机理与加速评价方法,展望了海洋防污涂料发展趋势。