Impact of cellulose nanofibers on cellulose acetate membrane performance

Abstract Membranes find applications across a wide spectrum of industries, including water treatment, energy production, and biomedicine. In this study, nonwoven membranes were fabricated using cellulose acetate (CA) as the primary component, with varying percentages of cellulose nanofibers (CNFs) embedded as reinforcement. These CNFs were prepared through an oxalic acid pretreatment (Oxalic-CNFs). Their incorporation into electrospun membranes represents an innovative approach, enhancing their mechanical properties for applications subjected to high loads and improving its functionalization capabilities. The impact of Oxalic-CNFs on membrane properties was investigated at nanofiber loadings ranging from 0 to 18 wt%. Membranes produced with 6 wt% Oxalic-CNF exhibited the superior physical and mechanical properties. This improvement can be attributed to the formation of threads with higher intrinsic strength, a reduction in pore size, and an increase in density. When higher percentages of CNFs were added, the membranes were not properly formed, because filaments were not continuous and the needle became clogged. The substructure of the membrane proved to be a critical factor for mechanical properties, with remarkable increases in tensile strength and elastic modulus (around 300%) when comparing 4–6 wt% Oxalic-CNF-loaded membranes to CA membranes.