Synthesis And Application Research Of Starch Graft Superabsorbent Resin

Starch graft superabsorbent resin is a kind of new macromolecular network polymer materials, which contains hydrophilic groups and therefore can absorb a large amount of water. Superabsorbents are widely used in various fields such as agriculture, petroleum industry, medicine and hygiene. This paper describes the means of systematic study on the preparation process, morphology and structural characterization, and the mechanism of the action of water on copolymers as well as the effect of the coated urea. As a result, it opens up a new path for the application research of superabsorbents.Starch graft superabsorbents can be prepared by the solution of polymerization at high monomer concentration. The influence of several technological conditions to the swelling properties of these absorbents has been investigated as following: the method of the starch pretreatment, the component of comonomers, pH of the neutralization, contents of the starch or monomer, initiator, crosslinker, and the post treatment. Further more, through the ortho-experiment, the optimum process parameters in this experiment system are obtained(wt%): acrylamide58.2%, arcyl acid29.7%, starch11.9%, initiator potassium ammonium persulfate (KPS)0.15%, crosslinking agent N,N ' -methylene-bis-acrylamide (MBA)3.5 × 10-3%. Under these conditions, resin absorbency with distilled water and a saline solution (0.9%NaCl) is 435.6g/g and 83.5g/g, respectively. Study also finds that if properamount of additive is added to the preparation system, the anti-electrolyte of absorbents would be improved.As a wonderful application of molecular simulation, the molecular dynamics method is used to research the action of water on polymer chains. It is discovered that molecular system reprents strong tendency to expand the network. Therefore, the expanded molecular would effect the water absorbency macroscopically. The results are in conformity with the Flory's network theory. The computer simulation offers a new research method and means for the study of the theory of the absorbing water mechanism. The copolymers are characterized by IR spectroscopy, thermal analysis and scanning electronic microscopy (SEM). It proves to be a better thermal stability, and the component of comonomers influences the resin's decomposition temperature and surface morphological characterization notably.Finally, the starch graft superabsorbents are applied to coat the surface of urea so as to form a slow releasing urea. The coated materials can play an important role for controlling nutrient release. The preliminary experiment result develops an effective way to produce release fertilizer.