Unique CNF nanofibers have been pre

Unique CNF nanofibers have been prepared combining highly preserved cellulose molar mass with up to 24% of hemicellulose content, in the form of a 0.2 nm “shell” coating surrounding 3.6nm “core” cellulose nanofibers based on theoretical estimation. The peracetic acid treatment is very mild since Mw of the CNF corresponds to a degree of polymerization DP as high as 3800,which is close to the expected value for holocellulose in native wood. These CNFs are also unique in terms of small nanofiber diameter (similar to cellulose microfibrils in the wood cell wall), improved yield, high stability in colloidal suspension (anionic CNF surface charge repulsion), and very low energy requirements for successful disintegration (only two passes in homogenizer). The reason for ease of fibrillation from holocellulose pulp is in the high hemicellulose content with anionic charge, which causes hydration and swelling. Furthermore,the resulting CNF nanopaper films show optical transparency similar to TEMPO-CNF, and better mechanical properties in tensile tests than any data known to us for wood-based CNFnanopaper. The lack of agglomerate defects (high optical transparency) and the high intrinsic strength of high molar mass fibrils contribute to the exceptional nanopaper strength. Thedistribution of the hemicellulose “polymer matrix” contributes to CNF dispersion, strong CNF-CNF adhesion and stress transfer between fibrils and between CNF lamellae. Compared with TEMPO-CNF, the present nanofibers provide much higher molar mass, preserved cellulose structure (no fibril surface derivatization) and shorter filtration time (lower anionic surface charge). Since the fibrils contain highly preserved biomacromolecules, they may also help to clarify structural details in plant cell walls.