mordant

mordant (môrˈdənt) [key] [Fr., = biting], substance used in dyeing to fix certain dyes (mordant dyes) in cloth. Either the mordant (if it is colloidal) or a colloid produced by the mordant adheres to the fiber, attracting and fixing the colloidal mordant dye (see colloid); the insoluble, colored precipitate that is formed is called a lake. The chemical compounds used as mordants are either acidic or basic. Acid mordants (e.g., tannic acid) are employed with basic dyes; basic mordants (e.g., alum, chrome alum, and certain salts of aluminum, chromium, copper, iron, potassium, and tin) are employed with acid dyes. Cloth to be dyed may be treated first with the mordant and then with the dye, or the mordant and dye may be applied together. The vividness of certain dyes that ordinarily do not require the use of a mordant may be markedly increased when one is employed.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on mordant from Fact Monster:

  • lake, in dyeing - lake lake, in dyeing, an insoluble pigment formed by the reaction between an organic dye and a ...
  • alizarin - alizarin alizarin , or 1,2-dihydroxyanthraquinone, mordant vegetable dye obtained originally from ...
  • fuchsin - fuchsin fuchsin or magenta, bright red dyestuff consisting of the mixed hydrochlorides or acetates ...
  • tartar emetic - tartar emetic tartar emetic, poisonous, odorless, transparent rhombic crystals or white powder with ...
  • zinc sulfate - zinc sulfate zinc sulfate, chemical compound ZnSO4, a very water soluble, transparent, colorless, ...

See more Encyclopedia articles on: Organic Chemistry