Synthesis of hydrogel with superwater absorbent (SWA) properties was performed from aqueous solution of cassava starch/acrylic acid blends with radiation processing technology using Co-60 gamma source at room temperature (~27ºC). The preparation conditions, such as irradiation dose (0 to 9kGy) and variation of cassava starch to acrylic acid ratio (1:1 and 1:2) in the feed solution were investigated. FTIR spectroscopy was used to investigate the molecular interaction of cassava starch/acrylic acid SWA. The thermo-gravimetric analysis (TGA) showed that cassava starch/acrylic acid SWA less thermal degradation than pure cassava starch. Biodegradation of SWA was investigated using α-amylase. The prepared SWA was applied as a soil conditioner to observe the growth of Chinese cabbage. The gel strength, gel fraction and swelling behavior were evaluated. With increasing irradiation dose as well as acrylic acid content, the high gel strength (2.15 kg/cm2) and gel fraction (88.5%) increased. The swelling ratio of SWA decreased with increased irradiation dose but it increased with increase in acrylic acid content in the feed solution. The swelling ratio of SWA in NaCl solution was lower than that of obtained in distilled water.
Cassava starch, Acrylic acid, Radiation, Superwater absorbent, Swelling behavior, Gel content, Gel strength