Extraction of Natural Dyes from Locally Grown Plants in Ethiopia and Dyeing of Cotton Fabrics
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Date
2017-11
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Addis Ababa University
Abstract
Natural dyes were the only colourants used for colouring of textiles beginning from ancient times to nineteenth century. Using of natural dyes are safe for human’s health and environmentally friend even though they have drawbacks such as not easily available in the market, needs complex processing steps and relatively poor fastness properties when compared to synthetic dyes. The purpose of this paper was to extract dye from impatiens tinctoria, allo and wild strawberry (Fragaria Vesca L.) plants grown in Ethiopia by using aqueous extraction method. Next crude dye yield of the extact was calculated and un-mordanted and pre-mordanted cotton fabric was dyed. For impatiens tinctoria the maximum yield was 21.3% while the least was 7.8%, in case of allo the maximum yield was 17.4% while the least was 4.5% where as for wild strawberry, the maximum crude dye yield was 18.4% while the least was 7.7%. Dyed fabrics were analyzed in terms of colour strength (K/S) and colour appendices (CIE L* a* b*) by using Data colour 6100. Dyed cotton fabric was also analyzed for its fastness properties like: rubbing fastness (dry and wet) by using crock meter, washing fastness (colour change and colour staining) by using atmospheric washer while light fastness was determined by solar box 1500. The results showed that cotton dyed by pre-mordanting with alum and ferrous sulphate showed increased depth of shade and improved fastness as compared to un-mordanted cotton fabric. The CIE L* a* b* result showed: For the wild strawberry, L* values were in the range of 42.56 to 84.26, a* lay in the range of 0.97 to 4.62 and b* values extended from 0.92 to 24.42; Allo lightness(L*) lay in the range of 34 to 85.63, a* values extended in between -2.01 and 4.9, b* lay in the range of 5.94 to 41.23 and Impatiens tinctoria lightness lay in the range of 65.23 to 81.31, a* values lay in the range of 3.52 to 4.70, the values of b* extended in the range of 2.84 to 13.92. The values of k/s also varied in between 0.381 to 14.12. The fastness results (>3 in case of washing and rubbing fastness and >5 for light fastness) indicated that they were in the range of commercially acceptable standards.
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Keywords
Cotton fabrics, Natural Dyes, Locally Grown Plants, Extraction