Ultrasound and Microwave Aided Natural Dyeing of Nettle Biofibre (Urtica dioica L.) with Madder (Rubia tinctorum L.)

In this study, eco-friendly 100% nettle bast bio-fibre fabric was dyed with eco-friendly natural dye, madder (Rubia tinctorum L.), using alternative dyeing methods such as ultrasound and microwave energy. Dyeings were performed with conventional-exhaustion, ultrasound and microwave methods using green tea and alum as mordants. The colorimetric, colour fastness properties and FTIR-ATR spectra of the nettle-biofibres dyed were investigated. Although the colour strengths of the microwave and ultrasound energy-aided dyeings were not as high as in conventional dyeings, the usage of microwave-energy in dyeing is important in terms of shortening the process time. All dyed nettle fabrics exhibited very high and commercially acceptable wash, dry-rub, alkaline-perspiration, acidic-perspiration and water fastness properties. Overall the conventional and ultrasound dyeing methods caused slightly higher light fastness than the microwave assisted dyeing method