Glactomannan gum was isolated from Gleditsia triacanthos seeds. It was then subjected to polymerization with acrylic acid using potassium persulfate initiation system. Products of the polymerization reactions are referred to as composites. Technical evaluation of the latter as thickening agent in reactive printing using cotton fabric was studied. The use of composite in printing cotton fabric with natural dye was also studied. It was found that the composite pastes are characterized by a non-Newtonian pseudoplastic behavior, and their apparent viscosity increases on increasing the concentration of acrylic acid. The composite can be diluted by water and its viscosity increases by neutralization. Printing pastes of the composite are very stable for storing, in contrast with those of natural gum which exhibit no stability for storing. It was also found that reactive prints thickened with the composite display relatively higher K/S than those thickened with native gum do. Meanwhile, K/S values of prints thickened with the composite are comparable with the values of those thickened with sodium alginate. Printed fabrics using the composite as a thickener exhibit soft handle, and their overall fastness properties are almost equal to, if not higher than, the properties of those printed using sodium alginate. On the other hand, printing of cotton fabric with a natural dye using the composite as a thickener results in prints with K/S values lower than those obtained using commercial synthetic thickener; but the overall fastness properties are nearly the same. (c) 2006 Wiley Periodicals, Inc.