Comparative analysis of sustainable nanocomposite cellulose nanofiber membranes with polycaprolactone, and polylactic acid

This study presents sustainable membranes prepared from cellulose nanofibers (CNF) using a simple solution-casting method, focusing on the incorporation of low weight percentages (1 %, 2 %, and 4 %) of polycaprolactone (PCL) and polylactic acid (PLA) to compare membrane performance. The nanocomposite membranes were evaluated based on thickness, wettability, electrolyte uptake, porosity, thermal behaviour, and mechanical properties. The results indicate that CNF-PCL membranes exhibit superior mechanical flexibility and stress tolerance but lower thermal stability, with a glass transition temperature (T_g) of 34.39 °C at 1 wt%, compared to CNF-PLA's T_g of 144.15 °C at the same concentration. The higher crystallinity and greater hydrophilicity of PLA enhance its stability. Additionally, CNF-PLA membranes demonstrate better interfacial compatibility due to hydrogen bonding between PLA's ester linkages and cellulose's hydroxyl groups, improving dispersion, liquid uptake, and overall hydrophilicity (34.66° for CNF-PLA vs. 72.64° for CNF-PCL at 1 wt% loading). These properties make CNF-PLA membranes more resistant to plasticisation and better suited for high-temperature applications. These findings highlight the crucial role of polymer selection and concentration in optimising CNF-based membranes for specific applications.