The swelling of alkali cellulose in sodium hydroxide solutions

Preparation of ultrastrength nanopapers using cellulose nanofibrils

“…By the NaOH treatment, the surface roughness and possible reaction sites on the nanofiber surface may increase, and thereafter help to increase the physical properties of the nanopapers. In addition, the NaOH treatment may be due to the increased surface area of the CNF in contact sites [11][12][13] and the improved crystallinity of the CNF [18]. The TMOS-treated nanopapers after the alkaline treatment/ homogenization and provided significantly higher tensile strength than the untreated-or alkaline-treated counterparts.…”

“…Alkaline treatment like sodium hydroxide (NaOH) eliminates natural products such as hemicellulose, lignin, extractives and waxes, presenting a rough surface and causing a fibrillation of cellulose in the natural fibers. Alkali treatment also affects the swelling of the natural fibers, providing an increased surface area and better ductility [11][12][13]. On the other hand, the chemical modification by silanes has been widely used in terms of the fundamental mechanism involved in the selfcondensation following pre-hydrolysis and reactivity of the siloxane toward the OH-groups of the cellulose fibers [14,15].…”