PREPARATION AND CHARACTERIZATION OF CARBOXYMETHYL STARCH (CMS) PRODUCTS AND THEIR UTILIZATION IN TEXTILE PRINTING

Starch and oxidized starches of different molecular sises were carboxy methylated under identical conditions. The degree of substitution (DS) of the so obtained. CMS samples increases by decreasing the molecular sise of starch which, indeed, is a manifestation of higher extents of oxidation. The latter was effected using different sodium hypochlorit e concentrations and the extent of oxidation was expressed as chlorine consumption. Pastes of these CMS samples exhibit pseudoplastic behavi our and their apparent viscosity decreases as the extent of oxidation increases. when used as thickeners in printing polyester fabric with d isperse dyes, these pastes bring about prints the colour strength (K/S ) of which are comparable with these for conventional thickeners, name ly commercial CMS and sodium alginate, Mixing of sodium alginate with the prepared CMS samples increases the efficiency of the latter to act as the thickening agent. The highest WS is obtained with CMS derived from starch oxidized using 1.25g active chlorine/l. Mean while, the co lour fastness properties of the prints towards rubbing, washing and pe rspiration are nearly equal to those fabrics printed using the convent ional thickeners such as sodium alginate or commercial CMS.