Chemical Nature of Direct Dyes
by : Rahul Sharma
Chemical Nature of Direct Dyes:
Chemically thety are salts of complex sulfonic acids..
Structure: More than 75% of all direct dyes are unmetallised azo structuers, great majority of them are disazo or polyazo types.
Iconoc Nature: Their iconic Nature is anionic.
Solubility: They are soluble in water.
Affinity: They have an affinity for a wide variety of fibers such as cotton, viscose, silk jute, linen etc. They do not make any permanet chemical bond with the cellulosic fibers but are attched to it via very week hydrogen bonding as well as vander waals forces. Their flat shape and their length enable them to lie along-side cellulose fibers and maximize the Van-der-Waals, dipole and hydrogen bonds.
