Technological evaluation of reactive cyclodextrin in cotton printing with reactive and natural dyes

Abstract

The chemical modification of cotton fabric with reactive cyclodextrin (R-CD) at different concentrations was carried out to enhance the printability of cotton fabric. The extent of the modification reaction was expressed as %N. Reactive and natural dyes were used to print cotton fabric before and after modification. Printing pastes were applied immediately after preparation or after 24 h of storage. Printing fixation was performed through either steaming or thermal treatment. The effect of the incorporation of R-CD in the printing paste of unmodified cotton was also studied. The results reveal that the extent of the modification reaction increased with increasing R-CD concentration and so did the color strength (K/S) of the printed sample regardless of the dye used. The results also revealed that K/S of the R-CD modified cottons were higher than that of the corresponding unmodified samples regardless of the method of fixation or the time elapsed before printing. On the other hand, the incorporation of R-CD in the printing pastes of reactive dyes, namely, Cibacron Brown 6R-P or Remazol Brilliant Red GG, had adverse effects, most probability due to the (a) increasing viscosity of the paste and/or (b) interaction of the reactive dye with R-CD hydroxyls. The opposite held true when a natural dye was used. Further, the incorporation of R-CD in the printing pastes had no effect on the rheological type of the pastes or the on overall fastness properties of the prints. Nevertheless, such an incorporation of R-CD was accompanied by a remarkable increase in the magnitude of the apparent viscosity. (c) 2006 Wiley Periodicals, Inc.