Active pigments protective properties

The investigations comprised zino pigmented coatings with the aim of testing the mechanism of their action and looking for ways of improving protective properties. With the use of impedance technique the meohanism for two periods of activity has been proven with these coatings. 

Model description of protective properties of active pigments... 

In Fig. 1.5, the principal reactions are summarised. In all cases, partial solubility of the pigments is required. For example, phosphate ions are formed and iron ions are released from the steel substrate, which precipitate at the surface as insoluble iron phosphate. This precipitate protects the surface from further access of corrosion stimulators. The precipitate can also seal and block voids in the coating close to the surface. These active pigments also have good protective properties on imperfectly prepared surfaces with remaining traces of rust. 

Unfortunately, there is no general rule for the application of such partly soluble active pigments, because each generic type of binder (or worse still, each specific binder) requires comparative trials and tests to optimise the protective properties and to provide knowledge about the necessary amount of pigments in the formulation. There are not even any rules of thumb for this problem, just trial and error. 

Example of self-healing active pigments with multi-protective properties... 

Fruifs and vegetables also contain ofher bioactive substances such as polyphenols (including well-known pigments anthocyanins, flavonols) and non-provitamin A carotenoids (mainly lycopene, lutein, and zeaxanthin) that may have protective effects on chronic diseases. Polyphenols and carotenoids are known to display antioxidant activities, counteracting oxidative alterations in cells. Besides these antioxidant properties, these colored bioactive substances may exert other actions on cell signaling and gene expression. 

Naturally occurring compounds such as phytochemicals, which possess anticar-cinogenic and other beneficial properties, are referred to as chemopreventers. One of the predominant mechanisms of their protective action is due to their antioxidant activity and the capacity to scavenge free radicals. Among the most investigated chemopreventers are some vitamins, plant polyphenols, and pigments such as carotenoids, chlorophylls, flavonoids, and betalains. Resolution of the potential protective roles of... 

Common properties of MBI-Rs and MBI-Ds are protective control activity against rice blast and inhibition of appressorium pigmentation of Pyricularia oryzae on agar plates or cellophane membrane [Hattori et al., 1994 Soma et al., 1999 Sie-verding et al., 1998]. Inhibition of spore liberation from leaf lesions is also commonly observed in all known MBI-Rs and MBI-Ds [Kitamura et al., 1976 Okuno... 

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