Water free dyeing of polypropylene fabric under supercritical carbon dioxide and comparison with its aqueous analogue

A facile one step method was developed for dyeing polypropylene fabrics with hydrazono propanenitrile disperse dyes under both aqueous and supercritical carbon dioxide mediums. The dyeing was carried out without any modification of the fabric and the results were compared. The dyeing parameters, mainly, dyeing concentration, temperature, time, and pressure in both water and scCO(2) mediums were studied. Also, the dye uptake expressed as colour strength (K/S) was measured for both dyeing mediums and it was observed that colour strength of the dyed polypropylene fibers in scCO(2) was significantly better than in water. The fastness properties (washing, rubbing, light and sublimation) of dyed samples in scCO(2) and water exhibited very good results. The ATR-FTIR of dyed samples in water and scCO(2) were found to be in good agreement with the structure of the dyestuff under application.