Green preparation of cellulose nanofibers via high-pressure homogenization and their film-forming properties

Cellulose nanofibers (CNFs) have captured extensive recognition owing to their unparalleled properties and environmental-friendliness. Green preparation process is an important step in realizing the sustainable development of CNFs. Herein, CNFs were prepared via high-pressure homogenization using commercial microcrystalline cellulose (MCC) as raw material, and subsequently employed for CNF films production by vacuum filtration. A comprehensive investigation was conducted to explore the influence of the homogenization processes on the stability, rheological characteristics of CNF suspensions, and the resultant properties of CNF films. The results showed that with the increase of homogenization pressure and cycles, the aspect ratio of CNFs increased, the dispersion stability of CNF suspensions improved, and the mechanical properties, hydrophilicity, air barrier property, and light transmittance of CNF films ascended, correspondingly. Under the homogenization pressure of 1000 bar with 15 cycles, the CNF sample exhibited an aspect ratio of 87.8 and a zeta potential of − 23.9 mV. Moreover, the CNF displayed favorable film-forming characteristics, with a tensile strength of 67 MPa, an air permeability of 4.8 µm/Pa·s, and a light transmittance of 70.2%. This work generally provides an effective and eco-friendly process for the preparation of CNFs and CNF films with high performance, which might hold great promise in biodegradable packaging application.