Preparation and Characterization of Phosphorylated Sesbania Galactomannan Gum Derivatives and Their Applications in Textile Printing

Abstract

Galactomannan gum isolated from the seeds of sesbania is subjected to chemical modification via phosphorylation. This is conducted via heating moistened blends of the gum with a mixture of orthophosphate salt. Three different phosphate ester derivatives are prepared by changing the reaction time. The %P increases from 0.07 to 0.12 to 0.61 by increasing the reaction time from 30 to 60 to 90 minutes. Modification of sesbania gum via phosphorylation increases the stability of their pastes to storing. Investigation of the rhelogical properties of these pastes indicate that they are characterised by non-Newtonian pseudoplastic behaviour. As the extent of the reaction increases, i.e. %P, the apparent viscosity of the pastes at a constant rate of shear decreases, while storing does not change the rheological characteristics of the pastes. Utilization of these derivatives as thickening agents in printing wool fabrics by using acid dyes indicate that phosphate derivatives of sesbania seeds could be used as a thickening agent in printing wool fabrics with acid dyes, where the K/S slightly decreases less than the commercial thickening agent named (Meypro gum) while the overall fastness properties are nearly identical.