Cationization of Eucalyptus grandis 4-O-methyl glucuronoxylan for application as a wet-end additive in a papermaking process

Abstract

Abstract Hemicelluloses extracted prior to kraft pulping can subsequently be introduced as wet-end strength additives in a papermaking process. The 4-O-methyl glucuronoxylan (Me-GluX) extracted from Eucalyptus grandis (E. grandis) under mild alkaline conditions was cationized and added to bleached kraft pulp (BKP) from E. grandis before refining. The cationization by 2,3-epoxypropyltrimethylammonium chloride (ETA) was done in a central composite designed experiment. Me-GluX with an average molecular weight of 52,000 g mol-1 contained 27% Klason residue. The cationic Me-GluX had degrees of substitution of the cationic side chain between 0.05 and 0.73 and uronic acid content between 6.1% and 12.7%. The cationic Me-GluX as a wet-end strength additive was compared to cationic starch (CatStarch 134) in handsheets. The handsheets with cationic Me-GluX showed improvement in tensile, burst, and tear indices and had lower air permeability than those with CatStarch 134 at dosages between 1.0% and 2.0%. Accordingly, cationized Me-GluX is a potential green wet-end strength additive, which could fully or partially replace the synthetic and starch additives.