EFFECTS OF MORDANTING METHODS OF DYE FROM VERNONIA AMYGDALINA ON COTTON FABRICS COLORATION
AbstractThe study investigated the effects of different methods of application of selected mordants on dyeing woven cotton with natural dyes from the leaves of Vernonia amygdalina. The effects analyzed are color fastness to; light, washing, wet and dry rubbing and color characteristics on CIELab color coordinates. The aqueous extraction method was used to extract the dye. Some selected mordants were used for dyeing viz; alum, potassium dichromate, ferrous sulphate, iron water and ash water. The mordanting methods used includes; pre-mordanting, simultaneous mordanting and post-mordanting. In the control dyeing without the use of mordants, very good fastness were registered with the following fastness ratings; for washing (4R), dry rubbing (5), wet rubbing (5) and light (5). The natural dye is therefore a substantive dye since it is very fast without mordants. The use of mordants improved color fastness to light from ratings of (5) to (6) for most mordants with post-mordanting methods registering the best results. Multiple colors were produced with different mordants therefore the plant leaves possess polygenetic dye. Post- mordanting method registered the best color strengths K/S values and it exhibited the best color saturation values C. In all cases post-mordanting method gave the best color characteristics with the most brilliant colors on fabrics and good color fastness with all mordants. However, there was no observable effect of mordanting methods on the yellowness or greenness of color.
Keywords: Vernonia Amygdalina, post-mordanting, color fastness, substantive dye