Synthesis Of Cassava Starch Grafted Superabsorbent Resin By Inverse Suspension

Cassava starch grafted superabsorbent resin is a kind of new functional polymer materials, which contains hydrophilic groups and therefore can absorb a large amount of water. Superabsorbent resins are widely used in various fields such as agriculture, petroleum industry, medicine and hygiene.The synthetic conditions of the super absorbent were investigated systematically. The suitable synthetic conditions were as follows:Cassava starch-g-acrylic acid superabsorbent was prepared by inverse suspension polymerization. The volume ratio of cyclohexane, as dispersed phase, to water was 3:1. The amount of Span-80, as dispersant, was 3%, based on the amount of monomer. The amounts of initiator and crosslinking agent were 6m mol/L and 0.05% based on the amount of monomers, respectively. The neutralization degree of acrylic acid was 45%. The reaction temperature and time was 65 °C and 3 hour, respectively. The best absorbability of superabsorbent in salt free water was 580g/g and 58g/g in 0.9% NaCl solution.Cassava starch-g-acrylic acid-acrylamide composite superabsorbent was prepared by inverse suspension polymerization. The volume ratio of cyclohexane, as dispersed phase, to water was 3:1. The amount of span-80, as dispersant, was 3%, based on the amount of monomers. The amounts of initiator and crosslinking agent were 6m mol/L and 0.03% based on the amount of monomers, respectively. The neutralization degree of acrylic acid was 80 %. The amounts of acrylamide and cassava starch were 20% and 22% based on monomers, respectively. The reaction temperature and time was 65 ℃ and 3 hours. The best absorbability of composite superabsorbent in salt free water was 1120g/g and 82g/g in 0.9% NaCl solution.The structures of two kinds of superabsorbent products were identified by FT-IR and SEM. SEM analysis result showed that the products had cavernous sandwich and floccules in the surface, which were of high absorbability and good at keeping water characters.Finally, the superabsorbent resins were applied to the fields of water-absorbent and water-reservation in agriculture. The experiment results showed that it is useful to increase the ability of preserving moisture in the soil and keeping water in crops.