Xylan Adsorption onto Unbleached Kraft Pulps Previously Treated with cationic Polyelectrolyte

MARÍA V. GALVÁN; PAULINA MOCCHIUTTI; MIGUEL A. ZANUTTINI

San Pablo

Congreso; Congreso Internacional de Celulosa y Papel ABTCP N° 44, 2011; 2011

ABTCP, CIADICYP

The aim of this work was to study the effects of the adsorption of an assembly of PAH (poly(allylamine hydrochloride) and X (xylan) polymers as polyelectrolyte bilayers on an unbleached recycled softwood kraft pulp. First, the kinetic of PAH adsorption on this pulp was determined. Then, the xylan adsorption on an untreated pulp and also on a previously PAH treated pulp was studied. Finally, the effects of the PAH/X bilayer on the swelling capacity and the tensile strength were determined. It was found that at pH 7.5 and 0.01N NaCl, short PAH adsorption times (lower than 60 min) are required to avoid its penetration on the cell wall. The xylan adsorption isotherms showed that is necessary a PAH pulp pretreatment to achieve its adsorption. When 0.3% PAH was added on pulp at pH 7.5 and 0.01N NaCl, the 55% of the xylan dosage used (1% xylan / o.d. pulp) was adsorbed on pulp. The tensile strength results showed that the adsorption of the PAH/X bilayer is a feasible technique for improving paper strength. In NaCl 0.01N and pH 7.5, the addition of 0.3% of PAH (corresponding to the fiber saturation dosage) and 1% of xylan on pulp showed a lightly decrease in pulp swelling but a clear increase of 23% in tensile strength.