ISSN:0892-7014    

DOI:10.1080/08927019209386214

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A membrane perfusion method for determining the minimum effective release rate (MERR) of antifouling agents is described. With this method precisely controlled and reproducible release rates can be achieved independent of water chemistry and flow near the immersed surface. Like immersed painted surfaces, it allows for the establishment of diffusion gradients so that fouling organisms may exhibit chemotactic responses to the released toxin. The method is applied to natural water microbial biofilms dominated by the protozoansZoothamniumspp. andCharchesiumspp. The MERR of TBTC1 for 90% fouling reduction was found to be 2–4 μg·cm−2d−1in the local estuary. This rate result is consistent with observations of antifouling paints in service, which have shown that biofilms can be present on TBT coatings which prevent barnacle and tubeworm fouling. Thus, alternative environmentally acceptable methods are needed if control of microbial biofilms, or slimes, is required.

ISSN:0892-7014    

DOI:10.1080/08927019209386215

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Barnacle adhesion measurements provide an excellent method of assessing the foul release characteristics of non‐toxic surfaces. This paper describes both tensile and shear force methods that have been developed for field applications. Selected data are presented and the results discussed with respect to the variables that affect the observed adhesion values.

ISSN:0892-7014    

DOI:10.1080/08927019209386216

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The development of non‐toxic or non‐polluting antifouling additives that can be formulated in practical coatings requires assays involving target organisms. Assays that test both for the effective and toxic concentrations of active compounds are useful. It is also desirable if the assay can provide information regarding the performance that can be expected if the compounds are incorporated into different matrices. Described here are the simple laboratory assays that have been developed using the barnacle,Balanus amphitrite, a common fouling organism found throughout temperate and tropical seas. One of the assays depends on synchronous year‐round mass culture, the procedure for which is described, of cypris larvae. The laboratory assays provide quantitative estimates of toxicity and settlement inhibition of barnacles. The methods described provide an excellent system for the use of barnacles to study the interaction of the test compounds and surfaces.

ISSN:0892-7014    

DOI:10.1080/08927019209386217

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Marine coatings incorporating two model inhibitors, benzoic acid and 2,4‐dinitrophenol, have been utilized to study controlled release and antifouling behaviour. Both non‐ablative and ablative coatings were developed to investigate two different mechanisms of inhibitor delivery to the coating surface. Non‐ablative coatings were based on commercial vinyl polymers to serve as binders for inhibitors dispersed either as pure compounds or in microcapsules. Release rates of the inhibitors into artificial seawater were measured and showed that the release from both simple films and microcapsules follow a diffusion‐controlled process and correlate with the Higuchi model. Ablative, or “self‐polishing”; coatings were also developed to study the delivery of the model inhibitors by seawater hydrolysis of pendant arm homopolymers having the model inhibitors covalently immobilized. Poly(vinyl benzoate) films deliver benzoate with zero‐order kinetics (constant rate) in the 10−1μg·cm−2d−1range after an initial faster delivery period. Poly(benzoic methacrylic anhydride) films deliver benzoate over three orders of magnitude more rapidly with first order kinetics, consistent with rapid bulk hydrolysis and slower erosion of the hydrolyzed polymer. Poly(2,4‐dinitrophenyl acrylate) hydrolyzes very rapidly (hours) in seawater.

ISSN:0892-7014    

DOI:10.1080/08927019209386218

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The effects of controlled release of two inhibitors (2,4‐dinitrophenol (DNP) or benzoic acid) from simple vinyl copolymer films on biofilm formation and activity were evaluated using a consortium of marine bacteria in a challenge assay. DNP is an uncoupler of membrane proton gradients. Benzoic acid is a repellant. The batch assays were conducedin vitro. Acriflavine direct cell counts (AFDC), iodonitrophenol (INT) tetrazolium dye reduction activity, presence of division septa, and biofilm DNA were used as response variables. DNP release at high release rates (15 to 70 μg·cm−2d−1) was inhibitory to cell attachment and activity. DNP release at low release rates (0·5 to 40 μg·cm−2·d−1) was inhibitory to biofilm activity. Benzoate release inhibited biofilm activity at high release rates (10 to 60 μg cm−2·d−1) and stimulated activity at low release rates (0·5 to 20 μg·cm−2·d−1). INT reduction, presence of division septa, and biofilm DNA content were more sensitive response variables than AFDC in assessing cause and effect. These data suggest that the controlled release of inhibitors from films can be used to evaluate both beneficial and detrimental effects on biofilm formation. Certain modes of inhibition (e.g. uncoupling) are more effective in controlling biofilm development.

ISSN:0892-7014    

DOI:10.1080/08927019209386219

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Generally applicable techniques for surface analysis are described for prepared coating surfaces, with the recommendation that they be utilized prior to any fouling‐release field trials. The effectiveness of these techniques to predict nontoxic fouling‐release is supported by citation of results from the performance of commercial coatings in both seawater and freshwater environments, and comparison with standard reference materials. It is no longer necessary to rely on assumptions about the types of surfaces that will most easily allow physical release of accumulated biofouling, since the field results now show why analysing the surfaces in advance of their aqueous exposure gives important clues about their likely fouling performance. Written test protocols that do not include this level of surface inspection limit understanding and do not aid it, since ambiguities in fouling results are not otherwise traceable to characterized initial coating qualities.

ISSN:0892-7014    

DOI:10.1080/08927019209386220

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The development of non‐toxic or non‐polluting coatings that provide effective control of biofouling is a high‐priority goal. The technology for such coatings involves antifouling methods other than traditional ones that rely on the sustained release of broad‐spectrum biocides. Rapid field‐testing procedures have been developed to facilitate and accelerate the evaluation of novel antifouling coatings. These procedures provide temporal discrimination of effectiveness which is important in improving potentially useful antifouling approaches that fail due to problems ranging from breakdown of active agents to physical failure of the coating. Two test procedures are described. The first provides information on intrinsic antifouling properties of coatings, and the second allows quantitative assessment of foul‐release properties. Rapid field assessment fills the need for a bridge between laboratory findings and the more laborious, costly, and time‐consuming tests based on long‐term exposure of coated panels or prototype ship coatings.

ISSN:0892-7014    

DOI:10.1080/08927019209386221

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A heavy growth of marine fouling organisms attached to shiphulls adversely affects operation of the ships, reduces their speed and increases their fuel consumption. At present toxic antifouling (AF) coatings are in use, but the recent concern about the environment makes it necessary to develop non‐toxic AF systems. The author's approach is based on the surface free energies that govern adhesion. Measurements on liquid barnacle adhesive indicated that solids (coatings) with surface free energies lower than 12 dynes·cm−1are needed to prevent attachment. Adsorbed monolayers of perfluorinated surfactants have the lowest known surface free energies. These monolayers were simulated by mixing such compounds into an epoxy coating matrix and by synthesizing acrylate, methacrylate and siloxane (silicone) polymers with long perfluorinated sidechains. These polymers showed much lower surface free energies than Teflon type perfluorinated polymers with no sidechains, and some showed excellent AF characteristics.

ISSN:0892-7014    

DOI:10.1080/08927019209386222

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Microencapsulation of natural antifouling compounds and their subsequent inclusion in polymeric coatings is a viable alternative to self‐polishing polymeric paint or rosin‐based ablative coatings. However, as naturally occurring compounds, the crude extracts of Octocorals(Renilla reniformis)or Pukalides, while found to be effective agents, are subject to both photolysis and chemical degradation in the marine environment. For these compounds to provide a viable alternative to persistent metallic toxicants such as organotins, they must be stabilized in the coating and released at their minimum effective dosages to provide for long term biofouling control.

ISSN:0892-7014    

DOI:10.1080/08927019209386223

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor