Nanocellulose-doped superabsorbent polymer for improved absorption properties in sanitary pad applications

An important disposable hygienic absorbent is the female sanitary napkin wherein superabsorbent polymers (SAP) are incorporated into it to increase the absorption capacity. Nevertheless, it has been discovered that SAPs have negative consequences on the environment and the user's health. The present study explores doping nanocellulose, into an acrylic acid-based SAP matrix to enhance absorption performance, leveraging nanocellulose's high surface area and hydrophilicity. Different SAP-nanocellulose compositions were tested, and characterizations like Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FT-IR), Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD) confirmed the successful incorporation of nanocellulose into the SAP structure. Performance tests showed enhanced absorption properties in SAPs doped with nanocellulose compared to unmodified SAPs. The 70-30 composition significantly outperformed unmodified SAP (100-0). Free absorbency was highest for unmodified SAP, while 70-30 almost equaled in equilibrium absorbency in distilled water, but excelled in saline, simulated, and animal blood. Schott's pseudo-second-order model and Fickian diffusion were used to identify the kinetic swelling of SAP. For absorption under load, 70-30 attained 28.7 g/g in saline, a 28.91 % increase over unmodified SAP. In CRC, 70-30 exceeded unmodified SAP by 37 % in saline and 53 % in simulated blood demonstrating enhanced stability and absorbency.