GVL pulping facilitates nanocellulose production from woody biomass

Nanocellulose is conventionally produced from woody biomass including wood, crops and forest/agricultural residues, by top-down methods. Due to biomass recalcitrance, pretreatment, with a subsequent bleaching process, is mandatory to break down the resistance of the composite for nanocellulose extraction. In the present study, gamma-valerolactone (GVL) pulping without further bleaching/purification was used for producing cellulose nanomaterials from wood. GVL pulp and bleached kraft pulp from Aspen were comparatively studied as starting materials for (2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl (TEMPO) cellulose nanofibril (TCNF) preparation. The TEMPO oxidation process and properties of the as-prepared TCNF solutions and films were studied to investigate the advantages of GVL pulp for TCNF production. There was no difference between nanocellulose prepared from GVL pulp and that from bleached kraft pulp. But, with the GVL pulping process, no subsequent bleaching process was required while the properties of the as-prepared nanocellulose were preserved. Nanocellulose was extracted from wood by green GVL pulping without bleaching, but with no impact on the properties of nanocellulose.