Naturally dyed wool mordanted

Mordanted, Natural-Dyed Wool and Silk Fabrics... 

The mordanting process had a profound effect on the shade and depth of shade of the natural-dyed wool and silk. This result was expected because the metal ions used in mordanting complex with the dye on the fiber (9). Copper, chromium, and iron mordants gave the greatest color changes. The morphology and chemical structure of the protein fiber also affect the nature of the interaction between the dye... 

To gain a better understanding of the effect of protein fiber type, dye, and mordant on sunlight and burial weathering processes, we dyed wool and silk with three phenolic dyes (found as major components in natural dye mixtures extracted from various plant sources) and post-mordanted samples of the dyed fabrics with five representative metal salts. We then exposed the unmordanted and the dyed-mordanted samples to simulated sunlight or soil burial and measured the differences in the color and tensile properties that resulted from these treatments. 

It has been recognised for centuries that certain natural dyes, including alizarin, kermes, cochineal and fustic, now known to contain o-dihydroxy phenolic or anthraquinonoid residues in their structures, can be fixed on natural fibres using oxides or salts of transition metals as mordants. Although mordanted wool dyed with alizarin showed excellent fastness, reproducibility of shade was difficult to achieve because of the variable composition of the raw materials available. The famous Turkey red, in which alizarin was applied to aluminium-mordanted wool in the presence of calcium salts, formed a metallised complex the nature of which remains in considerable doubt. 

Cotton and wool, even non-mordanted, are dyed in a dye bath containing sodium sulphate dyed natural wool gives up its Substantive colour in a slightly alkaline medium to white cotton. . . colouring matters... 

Natural and mordanted wools are equally dyed in a bath containing sodium sulphate and acidified with acetic acid... 

Cotton mordanted with aluminium or chromium is not dyed, but that mordanted with tannin Is strongly dyed in the above bath dyed natural wool gives up its colour to tannin-mordanted cotton in a slightly alkaline medium. ... 

Mordanted cotton is dyed little or not at all dyed natural wool does not give up its colour to white cotton in a slightly alkaline medium, and on acidification takes up again the colour given to the... 

Natural wool is dyed in/ the above bath, but the I colour is only slightly resistant to soap mor-l danted wool is dyed1 more intensely and gives faster colours the colour varies with the mordant... 

A naturally-occurring mordant dye, used extensively until a few years ago, and now probably the only one still in use, is logwood. It yields a navy blue or a black, with what is called a good bloom, when dyed on chrome mordanted wool. Until the advent of acid mordant dyes, which will be described later, it was the only dyestuff with which wool could be dj ed black with any measure of fastness. 

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