COMPARATIVE MICROWAVE-ASSISTED DYEING OF COTTON WITH CACTUS FRUIT, TURMERIC, AND BASIL: EFFECTS OF ALUM MORDANTING ON RUBBING FASTNESS

Abstract

The use of synthetic textile dyes is common in the textile industry despite their negative impacts on the environment and potential toxicity, and this has led to a revisit of natural dyes obtained from local plant sources [7], [11]. In this study, the dry and wet rubbing fastness of cotton fabric dyed with microwave extracted natural dyes from three sources available in Pakistan: cactus pear fruit (Opuntia ficus-indica), turmeric (Curcuma longa), and basil/tulsi leaves (Ocimum tenuiflorum) were investigated. The dyes were extracted using a domestic microwave and applied to the cotton fabrics by unmordanting and mordanting with alum by source specific microwave timings. The dry and wet rubbing fastness was tested using the Grey Scale (1-5 GS). The alum-treated cactus sample showed higher dry and wet rubbing-fastness ratings (3–4 GS and 5 GS, respectively) than the unmordanted sample (2–4 GS and 3–4 GS). In the case of turmeric, the dry rubbing fastness increased from 4 GS to 4-5 GS, while the wet rubbing fastness decreased from 3-4 GS to 2 GS. As for basil, dry rubbing fastness increased from 3 GS to 4 GS, while wet rubbing fastness decreased marginally from 4-5 GS to 3-4 GS. In general, the results obtained were source-dependent and did not reveal any combination of source and mordant which would rate the highest in both dry and wet conditions. This leads to an assumption that mordants need to be chosen taking into account their end purpose. However, since replicates and statistics have not been used, these results can only be considered preliminary.