Study on extraction and dyeing behavior of madder pigment on wool fabric

Abstract

It is firstly mentioned in this article to extract madder pigment by alkali, and the best processing conditions have been optimized through orthogonal experiment as: NaOH 5 g/L, temperature 75 °C, time 50 min, madder powder 100 g/L. The best dyeing processing conditions about madder applied on wool fabric have been concluded through orthogonal experiment, range analysis and single factor analysis such as: concentration of dye liquor 80 mL/L, pH value 4 temperature 100 °C, time 60 min, liquor ratio 1:40. Last it is shown, by color-stripping experiments of acetic acid, pyridinium liquor, pyridinium oxalate and DMF on dyed fabrics that: except hydrogen bond and Van der Waals Force formed between madder and wool fabric, there are comparatively strong ionic bond and covalent bond, i.e. ionic bond formed by oxygen negative ion on madder and amido positive ion on wool fabric; covalent bond formed by carboxyl and hydroxyl in madder and hydroxyl and carboxyl in wool fabric. Achievements in this article have established the theoretical foundation for madder being used in dyeing of textile.