Performance study of chia seeds, chia flour and Mimosa pudica hydrogel as polysaccharide-based superabsorbent polymers for sanitary napkins

This research reports the development and characterisation of three types of natural polysaccharide-based Superabsorbent polymers (SAPs) for application in sanitary napkins, namely chia seeds (Salvia hispanica L.), chia flour and Mimosa pudica hydrogel (MPH). Physical properties and performances of the materials were tested to determine the absorbing capacity, swelling capacity, absorbency under load and re-wet under load capacities. Antibacterial tests against Staphylococcus aureus and Escherichia coli and biodegradability tests were also carried out. Characterisation was carried out with Fourier transform infrared spectroscopy, field emission scanning electron microscope, energy dispersive X-ray spectroscopy and thermo gravimetric analysis. The results reveal that MPH had the highest absorbing capacity, at 5.24 g/g and lowest re-wet value, at 1.58 g, indicating MPH is a better SAP compared to chia seeds and chia flour. Scanning electron images of MPH revealed the macroporous structure of MPH with hollow channels that allow quick transportation of liquid. Antibacterial tests and biodegradability tests results indicate that MPH has potential antibacterial properties and biodegradability. Results of this work indicate that MPH has the highest potential to be used as SAP in sanitary napkins when compared to chia seeds and chia flour.