Study On Poly(Sodium Acrylate-acrylamide)/Bentonite Superabsorbent Composite Modified By Natural Macromolecules

Superabsorbent is a kind of new type functional polymer. They are loosely crossinked hydrophilic polymers, which have the ability to absorb considerable amounts of water or aqueous fluids in relatively short period of time and retain water under pressure. Because of their excellent characteristics,superabsorbents are widely used in agriculture, horticulture, sealing composite and medicine for drug delivery and so on.There are many hydrophile natural macromolecule compounds in natural,which have the ability to absorb or save considerable amounts of water, can be used as raw materials of superabsorbent composite. Used as materials of superabsorbent composite, those natural macromolecule compounds have some advantages: plentiful reserves, regenerative, low cost and innocuity, they can also be decomposed by animalcules. Using of them can reduce the pollution of environment. Starch and cellulose are mainly used as materials of superabsorbent composite commonly. In recent years, other natural macromolecule compounds such as polysaccharide,pectinose and algae also are used as materials of superabsorbent composite. In this paper, agar and sodium polymannuronate are used to ameliorate clay-polymer superabsorbent composite which were studied before.In this paper, poly(sodium acrylate-acrylamide)/bentonite superabsorbent composite and Polyacrylamide/bentonite superabsorbent composite which are modified by sodium polymannuronate or agar are synthesized by solution polymerization reaction. The influence of synthetic conditions, such as the concentration of crosslinker and intiator, the amount of sodium polymannuronate, agar and bentonite, proportion of acrylic acid and acrylamide on water absorbency of the superabsorbent composites was investigated. For poly(sodium acrylate-acrylamide)/bentonite superabsorbent composite modified by agar , the results show that the composites have high water absorbency and 0.9 wt% NaCl resistance when reaction temperature 85 oC, bentonite of 30%, agar of 1.0%, crosslinker of 0.01%, neutralization degree of 65%,initiator of 0.3%, and proportion of acrylic acid to acrylamide of 3: 1 and 2: 1, 1400 g/g and 95g/g respectively.For poly(sodium acrylate-acrylamide)/bentonite superabsorbent composite modified by sodium polymannuronate, the water absorbency and 0.9 wt% NaCl solution absorbency is 1300g/g ang 92g/g, respectively. And Polyacrylamide/bentonite superabsorbent composite modified by agar is 1220 g/g and 90g/g, respectively.The properties of the superabsorbent composite were measured by using IR, SEM and DSC respectively.The biodegradability of the superabsorbent composite under entironment was studied by soil-burial method.