Synthesis of biodegradable superabsorbent hydrogel from carboxymetylated cassava starch for use in sanitary pads

Abstract

The synthesis of biodegradable superabsorbent hydrogel from native and carboxymethylated cassava starch was carried out. The native starch isolated from cassava was chemically modified by carboxymethylation, and used in the production of the superabsorbent hydrogel. The FTIR spectra confirmed the presence of the carboxymethylated group on the modified cassava starch granule, while the X-ray diffractogram revealed the loss of crystallinity after the carboxymethylation of the starch. The DSC study showed that the gelatinisation temperatures and enthalpy of gelatinization (∆Hgel) of the starch was reduced after carboxymethylation. The superabsorbent hydrogel produced from the native and carboxymetylated cassava starch absorbed water and saline more than 100 times their dry weight, with the carboxymethylated starch – hydrogel having higher water absorbing power. The hydrogels also have good biodegradability, since about 70% of it was biologically degraded within 14 days. The physicochemical properties of the superabsorbent hydrogel produced from native and carboxymetylated cassava starch was at par with that of the commercial ‘synthetic’ hydrogel, while its biodegradability was better than the commercial hydrogel.  Keywords: biodegradable, carboxymethylation, cassava, starch, superabsorbent hydrogel