ELECTROKINETIC CHARACTERIZATION OF CATIONIC AMYLOPECTIN STARCH - SCREENING BY SALT AND SCREENING BY NANOSIZED SILICA PARTICLES

The screening of cationic amylopectin starch with salt has been invest igated using the technique of electrokinetic sonic amplitude. The dyna mic mobility was found to decrease as the electrolyte concentration in creases. The experimental data were satisfactorily explained by applyi ng a porous sphere model. The radius of the porous sphere could be use d to evaluate the contraction of the amylopectin molecule as the elect rolyte concentration increases. The screening of cationic amylopectin starch with nanosized silica particles was also followed using the tec hnique of phase analysis light scattering. The formation of large macr oscopic flocs could be explained in terms of available cationic and an ionic sites of the initially formed polyelectrolyte complexes between one amylopectin molecule and a number of small silica particles. (C) 1 997 Elsevier Science Ltd. All rights reserved.