Dyeing of woven polyester fabric with curcumin: effect of dye concentrations and surface pre-activation using air atmospheric plasma and ultraviolet excimer treatment

Dyeing of polyester fabric with curcumin was studied at 90 and 130 degrees C without and with a prior surface activation of polyester fabric using two different ecotechnologies: air atmospheric plasma treatment and ultraviolet excimer lamp at 172 nm. Without surface activation, dyeing with curcumin followed classical disperse dye behaviour, with higher dye uptake at 130 degrees C than at 90 degrees C, and saturation was readily reached at 2% dye owf at 130 degrees C with a colour yield of 22. Surface-sorbed curcumin molecules extracted with ethanol seemed to increase the colour yield values at 90 degrees C dyeing, while at 130 degrees C they decreased the colour yield values. When dyeing was carried out after a prior surface activation of the polyester fabrics, increased colour yield was observed at both dyeing temperatures for the ultraviolet excimer lamp only (with colour yield increasing from 2 to 10 at 90 degrees C and from 22 to 28 at 130 degrees C for a 2% dye owf). Indeed, both surface activation methods yielded hydrophilic species at the polyester fabric fibre surface, which were confirmed by water contact angle, X-ray photoelectron spectroscopy measurements and atomic force microscopy. However, the surface of the polyester fabric activated using plasma lost all of its hydrophilic species, reaching the water contact angle of untreated polyester when subjected to the dyeing conditions. The excimer treatment yields hydrophilic species that are more resistant to high temperature and pressure dyeing.