Colouration and bio-activation of polyester fabric with curcumin in supercritical CO2: Part I - Investigating colouration properties

Abstract In this study, a novel mordant free dyeing of polyester fabric with natural dye curcumin was investigated using water free and resource efficient super-critical carbon dioxide (scCO 2 ) dyeing process. Polyester fabric was successfully dyed for the first time in scCO 2 with curcumin without substrate pre-treatment or the use of any auxiliary chemicals with excellent colour strength and uniformity. The dyeing behaviour was found to be much more influenced by the system pressure followed by the dyeing temperature. The optimum dyeing condition which provided the highest colour strength and levelness values was 120 °C, 25 MPa, and 1 h of dyeing time. Moreover, the polyester samples developed using the optimum dyeing condition had excellent colour fastness to washing and rubbing. This process is a promising alternative for dyeing polyester fabrics in a sustainable and resource-effective way.