Protected by Polymer Coating

Coatings are also very common in food packaging. An example is tomato products that are corrosive to canning materials (such as iron) which must be protected by polymer coatings. Otherwise the food will be contaminated by metallic ions, and rupture of the can can occur. 

F. Mansfeld, The nse of electrochemical impedance spectroscopy (EIS) for the study of corrosion protection by polymer coatings—a review, J. Appl. Electrochem. 25 (1995) 187—202. 

F. Mansfeld, L.T. Han, C.C. Lee and G. Zhang, Evaluation of corrosion protection by polymer coatings using electrochemical impedance spectroscopy and noise analysis , Electrochim. Acta, 43,2933 (1998). 

K. Kolandaivelu, et al.. Stent thrombogenicity early in high-risk interventional settings is driven by stent design and deployment and protected by polymer-drug coatings. Circulation 123 (2011) 1400-1409, doi 10.1161/circulationaha.ll0.003210. 

Other thermoset resins such as epoxides, phenolics and polyurethanes are also used in reinforced form, as are some thermoplastic polymers. Many need to be protected by surface coatings if retention of properties after extended weathering is important. 

Lin, S. Shih, H. Mansfeld, F. (1992). Corrosion Protection of Metal Matrix Composites by Polymer Coatings. Corrosion Science, Vol. 33, No. 9, pp. 1331-1349, ISSN 0010938X... 

Coating of metal with protective insulating polymer coating (Section 12-1) or paint (Section 12-2) films is one of the most widely used corrosion-protection technologies. The isolating part of the film gives rise to a characteristic high-frequency capacitive response, represented by a parallel combination of FiLM I coated metals water penetration becomes an issue, as it leads... 

A final category of encapsulating materials consists of reaction products of the nucleus material and a reagent. For example, pellets of nitronium perchlorate have been encapsulated in shells of the less reactive amm perchlorate (AP) by exposing the pellets to ammonia gas. The fragile AP shells were usually further protected by a top-coating of A1 or a polymer film (Ref 2). The most familiar example of this process is the natural one wherein A1 powders (or articles) become coated with a protective coating of A1 oxide thru exposure to atmospheric air... 

The gold-coated outer surface is protected by an ultra thin window of polymer which has been coated with evaporated metal in order to minimise light transmission. 

For trace analysis in fluids, some Raman sensors (try to) make use of the SERS effect to increase their sensitivity. While the basic sensor layout for SERS sensors is similar to non-enhanced Raman sensors, somehow the metal particles have to be added. Other than in the laboratory, where the necessary metal particles can be added as colloidal solution to the sample, for sensor applications the particles must be suitably immobilised. In most cases, this is achieved by depositing the metal particles onto the surfaces of the excitation waveguide or the interface window and covering them with a suitable protection layer. The additional layer is required as otherwise washout effects or chemical reactions between e.g. sulphur-compounds and the particles reduce the enhancement effect. Alternatively, it is also possible to disperse the metal particles in the layer material before coating and apply them in one step with the coating. Suitable protection or matrix materials for SERS substrates could be e.g. sol-gel layers or polymer coatings. In either... 

Such sol-gel derived and ultraviolet (UV)-curable hybrids afford enhanced corrosion and mechanical protection of fibres compared to standard polymer coatings used by the fibre optics industry. These coatings are hard, transparent and impossible to strip since they become intimately bonded to the fibre surface during curing. 

In a more general way, the loading of metal salts into preformed block copolymer micelles has become the most used route for the incorporation of precursors into block copolymer nanostructures because it allows precursor loading with tolerable loading times, it is quite versatile, and it is applicable to a wide variety of precursor/block copolymer/solvent systems. The accordingly synthesized polymer-coated metallic or semiconducting nanoparticles exhibit increased stability, which results in, e.g., protection against oxidation as illustrated by Antonietti et al. [108]. 

Plastics. Part of the trend to substitute plastic and composite substrates for metals can be attributed to a desire to avoid the process of metallic corrosion and subsequent failure. Relatively little attention has been called to the possible failure modes of plastics under environments considered corrosive to metals. More extensive work should be conducted on the durability and life expectancy of plastic and composite materials under end-use environments. A further consideration is the potential for polymer degradation by the products of metal corrosion in hybrid structures comprising metal and polymer components. Since it is expected that coatings will continue to be used to protect plastic and composite substrates, ancillary programs need to be conducted on the mechanisms by which coatings can protect such substrates. 

On the other hand, metal/polymer coating systems are of interest because polymers have the potential to protect metals from the expensive onslaught of corrosion (over 20 billion dollars annually are spent in the U.S. for materials to replace corroded items)4). Polymer coatings can protect metals by acting as barriers, thus preventing the formation of a complete corrosion cell and the spread of corrosion from an initial corrosion site 5). 

SPME uses a polymer-coated fused-silica fiber, typically 1 cm 100 m, that is fastened into the end of a fine stainless steel tube contained in a syringelike device and protected by an outer stainless steel needle. In use, the plunger of the device is depressed to expose the fiber to the sample matrix so that the organic compounds to be sorbed onto the fiber. The plunger is retracted at the end of the sampling time, and then it is depressed again to expose the fiber to a desorption interface for analysis typically by GC or LC. In a recent variation of this technique, the so-called in-tube SPME, the polymer is not coated on a fiber but on the inside of a fused-silica capillary before analysis by LC. 

In an effort to develop a peroral application system for insulin, Saffran was the first to use azopolymers as protective colon delivery coating, by use of the aforementioned strategy of azo-linked prodrugs [58, 59], Originally, he used azo-linked copolymers of styrene and hydroxyethylmethacrylate to coat and protect the insulin. However, this approach is not restricted to hydroxyethylmethacrylate and can indeed be accomplished in the same way by an almost unlimited number of similar polymer types. 

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