Swelling Properties of Biodegradable Superabsorbent Polymers

Abstract

The size of the global market for biodegradable superabsorbent materials has been estimated at USD 120.64 billion. It is expected to register Compound Annual Growth Rate (CAGR) at 6.2% in 2018-2025. Superabsorbent polymers (SAP) are most frequently used in the hygiene products industry in the form of non-biodegradable poly (sodium acrylate). Most personal care products end up in landfills where decomposition times are estimated to be up to half a thousand years due to the synthetic polymers. Simple replacement of poly (sodium acrylate) with biodegradable superabsorbent polymer is a challenging task that includes several stages of scientific investigation. In this paper, the sorption of water and electrolyte solutions are discussed. Biodegradable superabsorbent polymers were obtained from polysaccharides, while a proportionally varying amount of the cross-linking agent was used. The absorption properties of deionized water and sodium salt solution were tested and the influence of polymer drying was discussed. The superabsorbent polymers were dried as follows: dM1-the sample was frozen at -20°C for 48 hours and was dried in vacuum (10^-2Tr) at room temperature for 48 hours; dM2-the sample frozen to -200°C for 2 hours and was vacuum (10^-2Tr) dried at room temperature for 48 hours; dM3-the sample was dried in a vacuum dryer (~10 Tr) at 50°C for 24 hours, dM4-the sample was frozen to -80°C for 24 hours and then freeze dried for 78 hours.