Holocellulose Nanofibers of High Molar Mass and SmallDiameter for High-Strength Nanopaper.

Wood cellulose nanofibers (CNFs)based on bleached pulp are differentfrom the cellulose microfibrils in the plant cell wall in terms oflarger diameter, lower cellulose molar mass, and modified cellulosetopochemistry. Also, CNF isolation often requires high-energy mechanicaldisintegration. Here, a new type of CNFs is reported based on a mildperacetic acid delignification process for spruce and aspen fibers,followed by low-energy mechanical disintegration. Resulting CNFs arecharacterized with respect to geometry (AFM, TEM), molar mass (SEC),and polysaccharide composition. Cellulose nanopaper films are preparedby filtration and characterized by UV–vis spectrometry foroptical transparency and uniaxial tensile tests. These CNFs are uniquein terms of high molar mass and cellulose–hemicellulose core–shellstructure. Furthermore, the corresponding nanopaper structures exhibitexceptionally high optical transparency and the highest mechanicalproperties reported for comparable CNF nanopaper structures. [ABSTRACT FROM AUTHOR]