Study On Modification Of Superabsorbents Based On Acrylic Acid

In this paper, design principle of component and structure and anti-ultraviolet properties of superabsorbents based on acrylic acid were studied, modification of humic acid on superabsorbents based on acrylic acid and design of core-shell structure of superabsorbents based on acrylic acid were studied as well.Theory of flexible macromolecular chain was used to investigate relationship between properties and changes of crosslinked networks of superabsorbents, and it was thought that the swelling behavior and gel intensity were determined by the flexibility of macromolecular chain of the superabsorbents. The bigger of the crosslinking density, the more flexible of the macromolecular chain of the superabsorbents, and the superabsorbents can absorb much more water, while the gel intensity was lower. The absorbing rate was significantly influenced by the shape of the superabsorbents particles, the shape of the superabsorbents particles made by solution polymerization was iiregular and the absorbing rate was low, while the shape of the superabsorbents particles made by inverse suspersion polymerization was even sphericity and the absorbing rate was rapid.The aging mechanism of the superabsorbents which N'N-methylene-bis-acrylamide was used as crosslinker was crosslinker hydrolyzed by ultraviolet, leading to the crosslinked structure of the superabsorbents disassembled and the superabsorbents lost absorbency and water-keeping ability; the anti-ultraviolet properties of the superabsorbents can be evaluated by loss of weight and can be tested by radiation of ultraviolet. The decomposing kenetics of the superabsorbents showed the decomposing rate was controlled by the intensity of ultraviolet when the intensity of ultraviolet was weak, while the decomposing rate was controlled by the hydrolyzing reaction when the intensity of ultraviolet was strong.The anit-ultraviolet properties of the superabsorbents made by copolymerization of acrylic acid and acrylamide were studied, the results showed when the neutralization degree of acrylic acid and the dosage of crosslinker, acrylamide increased, the the anti-ultraviolet properties increased, while the initiator and monomers concentration had no influence on the anit-ultraviolet properties of the superabsorbents.