Influence of the initial carboxylic groups and degree of polymerization of cellulosic pulps on final lignocellulosic nanofibers (LCNF) properties

FELISSIA, FERNANDO ESTEBAN; RAMÍREZ, ALEJANDRA ITATÍ; AREA, MARIA CRISTINA; EHMAN, NANCI VANESA; VALLEJOS, MARÍA EVANGELINA

Córdoba

Workshop; 2nd International Workshop of Biorefinery of Lignocellulosic Materials; 2019

The aim of this work was evaluate the influence of initial characteristics of cellulosic pulps on final properties of lignocellulosic nanofibers (LCNF). Six pulps based on pine sawdust, eucalyptus sawdust and sugarcane bagasse with different pulping process and bleaching were evaluated. Carboxylic groups and degree of polymerization of initial pulps were measured. The pulps were subjected to TEMPO mediated oxidation accordingly to (Saito and Isogai, 2004) and then were passed through a colloidal grinder to break completely the fibril bundles. The degree of fibrillation, morphology, surface chemical charge, and rheology of LCNF were characterized and analyzed using several techniques. The rheology properties of LCNF were variable; eucalyptus sawdust LCNF (12.2 Pa.s) showed lower viscosity than pine and sugarcane bagasse values, the highest value was reached for a pine bleached kraft pulp (792.7 Pa.s). The carboxylic groups of LCNF varied between 638 µmol over dry pulp (odp) for pine unbleached soda/oxygen LCNF and 1005 odp for pine bleached kraft LCNF. Carboxylic groups content is directly related with viscosity (+0.94), the increase of degree of oxidation manifests with the increase in viscosity. Morphology analysis showed differences between the pulps reached low levels roughness in LCNF film (0.38 µm) respect to pine LCNF samples (1.39 µm for pine bleached kraft LCNF). The results of the influence of the initial characteristics on the properties of the LCNF dispersion will allow the election of an adequate biorefinery scheme in accordance with the application of the LCNF.