Analysis of colour strength, colour fastness and antimicrobial properties of silk fabric dyed with natural dye from red prickly pear fruit

In the present study, a natural dye is extracted from red prickly pear fruit (Opuntia ficus-indica) and is applied on the silk fabric using natural (myrobalan) and synthetic (copper sulphate) mordant. The dyeing of silk fabric is carried out using two different routes, namely, pre-mordanting and post-mordanting at different mordant concentrations and the dyed silk fabric was evaluated for its colour strength, colour fastness and antibacterial properties. The colour strength (K/S) was found to be higher in the post-mordant-processed fabric with the use of synthetic mordant compared to pre-mordanting and with the use of natural mordants and highest colour strength was observed at the mordant concentration of 6% and at a pH of 6 in all the cases. The colour fastness properties of the fabric also found to be improved in post-mordanting with use of synthetic mordants. The antimicrobial efficacy was also evaluated both in terms of zone of inhibition (qualitative analysis [SN195920]) and bacterial reduction % (quantitative analysis [AATCC 100]), against dyed silk fabric samples against on Staphylococcus aureus and Escherichia coli.