Characterisation and swelling–deswelling properties of superabsorbent membranes made of PVA and cellulose nanocrystals

ABSTRACT

Novel superabsorbent membranes (SMs) consisting of polyvinyl alcohol (PVA), cellulose nanocrystals (CNCs) originated from rice husk (RH), glutaraldehyde (GLA) and glycerine (G) were manufactured by a compression moulding process. RHs were used to isolate pure CNCs via mechanical and chemical treatments. RHs were used to improve water-retention. Glycerine was used to increase the elasticity of the SMs. These SMs were characterised by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), mechanical testing and differential scanning calorimetry (DSC). SMs showed a greater equilibrium swelling capacity than neat cross-linked PVA. Moreover, the water transport mechanism of all SMs was found to follow Fickian diffusion. SMs exhibited good pH-dependent swelling reversibility and high-water retention capacity, making them more efficient water-retention materials. The biodegradability of the SMs was evaluated against environmental changes. The SM was also investigated for antimicrobial activity against pathogenic bacteria such as Candida Albicans (fungus), Bacillus subtilis (G+ Ve), Staphylococcus aureus (G+ Ve), Proteus Vulgaris (G-Ve) and Erwinia Carotovora (G-Ve). The hydrogel membrane has been found to act as a useful water reservoir, which may make it useful in agricultural applications.

KEYWORDS:

• Superabsorbent membrane
• cellulose nanocrystals
• swelling kinetic
• antimicrobial activity

Disclosure statement

No potential conflict of interest was reported by the authors.