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Fourier-Transform Infrared Spectroscopy: (a) St, ZnO-NPs-St, and ZnO-NPs. (b) Thermogravimetric analysis of ZnO-NPs and ZnO-NPs-St.
Source publication
The objective of this study was to examine the combined protection effect of a two-layer system consisting of organic corrosion inhibitors (tannins derived from the bark of radiata pine) and anodic protection by means of the incorporation of zinc oxide nanoparticles modified superficially by chemical methods to improve the protection of metallic st...
Contexts in source publication
Context 1
... the encapsulation process of ZnO-NPs with styrene studied by FT-IR. The IR spectrum in Figure 3a shows the characteristic curves of the main raw materials and encapsulation process: styrene (St), ZnO-NPs-St, and ZnO-NPs. The characteristic signals of styrene, mainly the signals at 3020-3100 cm −1 , are associated with the C-H stretching band, in addition to the C-H bending bands at 1487-1432 cm −1 , and finally the absorption bands between 1630 and 1500 cm −1 , corresponding to the vibration of the aromatic C=C bond. ...
Context 2
... the other hand, the effective coupling of styrene molecules to the surface of ZnO-NPs was studied by TGA. Figure 3b shows a considerable loss of mass of the encapsulated nanoparticles with respect to the unmodified ZnO-NPs with values of 2.54% and 2.84%, respectively. The weight loss corresponding to temperatures below 350 °C is attributed to styrene. ...
Citations
... The coordinate interactions between tannins and iron ions have been extensively studied and produce black mono and bis-complexes, denominated iron tannates [33,40]. The coating adhesion enhancement by natural tannins, including tannic acid (Fig. 1b), on steel substrates was investigated [33,[41][42][43][44][45][46][47][48][49][50]. Wang et al. achieved a highly performed tannic acid-based additive as an adhesion promoter for a UV-curable coating for low-carbon steel. ...
... Pine tannins (condensed) have been extensively studied as active compounds in primer formulations [82,83,93]. The second most employed tannins for this purpose are the tara ones [75,76,80], which are hydrolysable. ...
... As discussed in the following and summarized in Table 2, tannins are rarely used alone as primers or adhesion promoters [84]. The preparation of a primer or adhesion promoter layer often foresees the combination of tannins with phosphoric acid [77,78] or a polymer such as polyvinyl butyral [75,76,82,83], epoxy [93], or acrylic [77,78] resins and their application on the substrates by brushing [75][76][77][78]82,84], spraying [80], or bar coating [79]. ...
... The introduction of metal oxide nanoparticles, such as ZnO, Fe 2 O 3 , and TiO 2 , in epoxy resin-based coatings provides a more uniform distribution and thus, a better protection performance against corrosion [94]. In this framework, Ramírez et al. successfully incorporated tannins from Pinus radiata barks into an epoxy-based primer enriched by zinc oxide nanoparticles to improve the functionality of the coating system, such as the resistance against aggressive agents, mechanical response, and film adhesion [93]. ...
Corrosion is recognized as an unavoidable phenomenon and steel, particularly carbon steel, is strongly susceptible to corrosion. Corrosion damages cause serious material, energy, and economic losses as well as negative impacts on the environment. As a result, research interest has been focused on the development of effective corrosion prevention strategies. However, some of the most commonly used corrosion inhibitors, such as chromates and pyridines, are harmful to human and environmental health. Polyphenols are natural, non-toxic, and biodegradable compounds from plant sources or agricultural by-products. Polyphenols’ chelating capacity has been acknowledged since the 1990s, and tannins, in particular, have been widely exploited as green rust converters in phosphoric acid-based formulations to recover rusty steel. Polyphenolic compounds have recently been investigated as a method of corrosion prevention. This review overviews not only the polyphenolic rust converters, but also the application of green anticorrosive coatings containing polyphenols. Moreover, polyphenols were discussed as an active component in corrosion-inhibiting primers to also promote strong adhesion between the steel surface and the topcoat layer. Finally, an overview of the use of polyphenolic additives in coatings as sustainable systems to improve corrosion resistance is provided.
