Textile Dyes
Colored compounds that bond to fibers.
Practise Biochemistry, Environment & Industry All Biochemistry, Environment & Industry topics
Colored compounds that bond to fibers.
Practise Biochemistry, Environment & Industry All Biochemistry, Environment & Industry topics
Dyes are coloured compounds that bind to fibres, and the binding can be physical or chemical. Ionic or hydrogen bonds attach direct dyes to cotton and wool, reactive dyes form covalent bonds with hydroxyl or amino groups in the fibre, and disperse dyes are small insoluble particles that diffuse into synthetic fibres. Vat dyes such as indigo are applied in a soluble reduced form and then oxidised back to the insoluble pigment inside the fibre. Mordants, such as alum or metal salts, form coordination complexes that fix dyes to natural fibres. Dye effluent must be treated before it is released.
Key ideas: Dyes bind fibers by different mechanisms: direct and reactive dyes (reactive forms covalent bonds with cellulose OH), vat dyes (indigo, insoluble, reduced to soluble leuco form, then air oxidized in fiber), mordant dyes (metal ions such as Al3+ link dye to fibre), acid dyes for wool and nylon, disperse dyes for polyester. Color comes from chromophores (azo group, N=N) with auxochromes.
Common mistakes and connections: Mistake: thinking all dyes bond the same way; fibre chemistry decides which class works. Azo dyes make up over half of all dyes and some break down to carcinogenic amines. Dye effluent colors water and blocks light. Links to conjugation and light absorption, organic functional groups.
Indigo absorbs orange-red light near 610 nm, so the light we see from it is blue, the colour of denim. The interactive lesson shows this as a live animation or chart.
Indigo is a vat dye that gives denim jeans their characteristic blue colour.
Colored compounds that bond to fibers.
Textile Dyes is a intermediate topic in Biochemistry, Environment & Industry. It builds on the vocabulary of beginner topics in this area.
Study these earlier topics in Biochemistry, Environment & Industry first: Fireworks Chemistry, Matches, Photography Chemistry.
The next topics in Biochemistry, Environment & Industry are Chemical Engineering Basics and Chemical Reactors.
Yes. The interactive lesson includes a self-check question on Textile Dyes, and the Biochemistry, Environment & Industry quiz draws on every topic in this area.
Textile Dyes is topic 111 of 127 in Biochemistry, Environment & Industry.
Browse all 127 topics in Biochemistry, Environment & Industry