POLYELECTROLYTE COMPLEXES OF XYLAN AND CHITOSAN. EFFECTS OF THE ORDER OF ADDITION AND IONIC STRENGTH.

CARLA N. SCHNELL; MARÍA V. GALVÁN; MARÍA S. PERESÍN; MIGUEL A. ZANUTTINI; PAULINA MOCCHIUTTI

Viena

Simposio; 8th ISWFPC International Symposium on Wood, Fiber and Pulping Chemistry; 2015

Boku University- Department of Chemistry

Polyelectrolyte complexes (PECs) formed from two natural polyelectrolytes, xylan (Xyl) and chitosan (Ch), were obtained and characterized. The order of addition (Xyl on Ch solution, and Ch on Xyl solution), and two ionic strengths in the liquid medium (0.01N and 0.1N NaCl) were considered. It was found that the shapes of the turbidity curves depended on the order of addition of the polyelectrolytes, and to a lesser extent, on the ionic strength of the media. Cationic complexes (CatPECs) and anionic complexes (AnPECs) were prepared at the two different ionic strengths and characterized by measuring the charge densities, particle size, and z-potential. Using a Britt Dynamic Drainage Jar, it was found that the amount of PECs adsorbed onto recycled unbleached softwood kraft fibers was low. Nevertheless, it was enough for improving papermaking properties. Particularly, the addition of CatPECs and AnPECs on pulp increased 53% and 48% the dry tensile strength, and 74% and 49% the compressive strength, respectively.