Dyeing of modified cotton fibres with disperse dyes from supercritical carbon dioxide

Cotton, previously modified by reaction with benzoyl chloride and sodium benzoylthioglycollate, was dyed with disperse dyes APAN and DY82 in supercritical carbon dioxide at 100 degrees C and 300 bar. This process is compared with the dyeing of polyester and unmodified cotton under the same conditions. The modification of the cotton fabric was confirmed using FTIR. The dyed fibre was also subjected to an ISO 2 wash fastness test. The colour yields were assessed by K/S measurements before and after washing. Microscopic cross-section analysis for both modified and dyed cotton and for polyester was also performed.