Browsing by Author "Ragheb, A. A."

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Preparation, characterization and technological evaluation of CMC derived from rice-straw as thickening agents in discharge, discharge-resist and burn-out printing
(ELSEVIER SCI LTD, 2012) Ragheb, A. A.; Nassar, S. H.; Abd El-Thalouth, I.; Ibrahim, M. A.; Shahin, A. A.
Carboxymethyl cellulose samples of different D.S. values were prepared from rice straw via pulping followed by etherification with monochloroacetic acid under the catalytic action of sodium hydroxide. The prepared derivatives were assessed for D.S., rheological properties as well as suitability as thickening agents in different printing styles. It was found that carboxymethyl cellulose derived from rice straw is characterized by a non-Newtonian pseudoplastic behavior and its apparent viscosity at any specific rate of shear depends on the D.S. All the prepared derivatives could be used successfully as thickening agents in discharge and/or discharge/resist printing of cotton fabrics. Furthermore, they could be used also as thickening agent for burn-out printing style of wool/polyester blended fabrics using sodium hydroxide. Attractive samples could be obtained via using these techniques. (C) 2012 Elsevier Ltd. All rights reserved.
Technological evaluation of reactive cyclodextrin in cotton printing with reactive and natural dyes
(JOHN WILEY & SONS INC, 2006) Hebeish, A. A.; Ragheb, A. A.; Nassar, S. H.; Allam, E. E.; Abd El Thalouth, J. I.
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.