Functions of pigments

Most coatings are formulated to have two important functions aesthetic and protective. Pigments are incorporated into coatings to contribute to both of these functions. 

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COGDELL R (1988) The function of pigments in chloroplasts . In Plant Pigments. T W Goodwin (ed) London, Academic Press. 

However, the transparency number is not only a function of pigment and vehicle it usually changes with the thickness of the layer (e.g., the pigment surface concentration). The transparency number of a sample which is applied at a thickness somewhere in the interval between two limits hi and h2 is calculated as follows ... 

Figure 6. Scattering coefficients as a function of pigment volume concentration...

For white pigments, the hiding power can be expressed through the Lorentz-Lorenz equation (4) as a function of pigment, and medium, nm,... 

Fig. 10. Photooxidative Degradation of Pol3nner I as a Function of Pigmentation - Accelerated Weathering Dry Cycle...

The figure shows particle size distributions (frequency function) of pigments (CuaO, ZnO and mixtures Cu20/Ti02 and ZnO/Ti02) in coatings (named P2, P4, P6 and P7). It can be seen that ZnO contains mainly submicron particles CU2O has a bimodal distribution of sizes with one peak in the submicron domain. 

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