The purpose of the thesis was to explore the possibilities of using waste from the food processing industry to obtain dyes for dyeing silk fabric (raw and degummed silk). Pomegranate peel extract was used for bio-mordanting of the samples, while avocado pit, olive leaf, and hop (including hop cones) extracts were used for dyeing. The pomegranate peel extract used for bio-dyeing was prepared in a concentration of 2 g/l. The extracts for dyeing were prepared at a concentration of 100 g/l. Dyeing and bio-mordanting were carried out at a bath ratio of 1:40 for 60 minutes at 60 °C. The colour of the unmordanted, bio-mordanted, and dyed samples was quantitatively evaluated on a reflection spectrophotometer. The colour values of the samples were also measured after washing and light fastness tests. Regardless of the natural dye or substrate used, the bio-mordanted samples had a higher colour depth, were darker, and were more yellow than the unmordanted samples. The deepest and darkest silk was dyed with hop leaf extract. The functional properties of the samples, i.e. antioxidant activity, and ultraviolet protection factor (UPF) were determined. Raw silk samples offered a higher UV protection than degummed silk samples, while bio-dyed samples offered a higher level of protection (satisfactory or good) than undyed samples. The antioxidant activity of all samples was low. After washing, all samples, except for the uncoloured and unmordanted ones, became lighter, less yellow, and their colour depth decreased. The wash fastness of samples dyed with hop resin and avocado pit extract was improved by bio-mordanting. Bio-mordanted samples dyed with olive leaf extract, hop resin, and undyed bio-mordanted samples had better light fastness than non-mordanted samples. After washing, the UPF of degummed silk decreases.
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