A biodegradable cellulose fibrous membrane comprising cellulose microfibers and nanofibrils with enhanced interaction through crosslinking structure

The petroleum-based materials are widely used in daily life, which are inherently tough to degrade, increasingly polluting the environment and affecting human health. Cellulose fibrous membrane, the ubiquitous, low-cost, and biodegradable material, can serve as a promising substitute. Herein, the biodegradable cellulose fibrous membranes were constructed with cellulose microfibers made from wood particle fibers (WPF) and the mechanical properties were enhanced by introducing the crosslinking system. The cellulose fibrous membrane made of the original WPF showed low tensile strength (0.1 KPa) and elastic modulus (1 MPa). By adding 10 wt% cellulose nanofibrils (CNFs), the prepared cellulose fibrous membrane exhibited an increase in tensile strength (0.525 MPa) and elastic modulus (535 MPa), respectively. To further improve the mechanical properties, the sodium alginate (SA) and Ca2+ were introduced to crosslink with the CNFs and promote the interaction among SA, CNFs and microfibers, which resulted in a substantial increase in tensile strength (5.62 MPa) and elastic modulus (1660 MPa) due to the formation of the interpenetrating entanglements and anchors. The normalized fracture energy of crosslinked hybrid cellulose fibrous membrane was 100.38 times higher than that of the original WPF membrane and 16 times higher than that of the un-crosslinked cellulose membrane comprising CNFs. This strategy can serve as the foundation for preparing a mechanically enhanced cellulose fibrous membrane via crosslinking, making it possible to replace petroleum-based plastics.