Isolation of cellulose microfibers and nanofibers by mechanical fibrillation in a water-free solvent

Cellulose from vegetable sources is the most abundant biopolymer on earth. In plants, cellulose is a reinforcement element that conforms to a hierarchical structure. Cellulose micro-/nanofibers can be isolated from the cell wall by top-down strategies involving mechanical processes to be used in applications as a reinforcing material. Nonetheless, its use has been limited as its extraction in an aqueous medium is unfavorable when employed in low-hydrophilic matrices. Therefore, this work proposes a novel homogenization route in which cellulose micro-/nanofibers are directly obtained and dispersed in propylene glycol (PG), which generates more possibilities for these (nano) structures in applications that require water-free environments. Moreover, the influence on the cycle numbers in the morphological, chemical, thermal, and rheological properties was researched. Thus, the obtained micro-/nanofibers presented TEM diameters even below 20 nm. XRD analysis evidenced crystalline planes located at 11 0 , 110, and 200, and crystallinity degree values up to 80