Study On The Synthesis And Properties Of Antibacterial Superabsorbent Polymers

In this thesis, according to the applications and recent researchs on thesuperabsorbent, four antibacterial superabsorbent polymers such as CTS-g-PAA,CMCTS-g-PAA, PAA/Ag+and PAA/BP were prepared by solution polymerization,using chitosan, carboxymethyl chitosan, silver ion and butyl paraben as antibacterialadditives. On the basis of investigation on synthesis conditions and properties of thesuperabsorbents, by comprehensive comparisons on the properties of the fourantibacterial superabsorbents, analyzing their advantages and disadvantages, whichproviding guidance on the development and application of the antibacterialsuperabsorbents. Finally, the salt-resistance and degradation were studied, which canhelp us improve the performance of the superabsorbent. The main results wereobtained as follows:1. For the purpose of obtaining a superabsorbent which had antibacterial activity.A series of chitosan graft (acrylic acid) superabsorbent composites were synthesizedby solution polymerization, using potassium and sodium bisulfite as initiator,N,N′-methylenebisacrylamide as crosslinker. The infrared absorption spectrum of thesuperabsorbent showing that the graft polymerization between chitosan and acrylicacid. The polymer synthesized in the optimal reaction condition had high waterabsorbency and high antibacterial activity, which can absorb685times deionizedwater, and graft yield was84.2%; In the drum wind dry condition of65℃, the waterretention rate was67.2%after2h. The copolymers obtained were inhibitory to thegrowth of Escherichia coli and Staphylococcus aureus, bacteriostasis rate was65%~75%. The uniform design was used to establish the model of absorbency andantibacterial activity which was influenced by main parameters of superabsorbent. Itproved that this prediction model is effective through experiment validated.2. By comprehensive comparisons on the properties of the four antibacterialsuperabsorbents: CTS-g-PAA, CMCTS-g-PAA, PAA/Ag+and PAA/BP, analyzedtheir antibacterial activity, water absorbency, degradation, stability and production cost, found that PAA/Ag+had best antibacterial activity. But its water absorbency anddegradation were not so good. It was unstable in the air condition, can easily reactwith negative ion of the solution in using process which would lose antibacterialactivity. The production cost was high. So it was difficult to be applied in practice.PAA/BP had good water absorbency and antibacterial property, but it was hard to bedegraded in the natural environment. If it was used on a large scale, would coursepollution to the environment. CTS-g-PAA and CMCTS-g-PAA had good waterabsorbency and antibacterial property, in the natural environment can degrade, andthe production cost was low, were more likely to achieve large-scale production. Sodeveloped the products of CTS-g-PAA and CMCTS-g-PAA, had broad marketprospects.3. Take the chitosan superabsorbent for example, the salt-resistance property ofthe superabsorbent can be improved by the introduction of non-ionic hydrophilicmonomer acrylamide. As the acrylamide content was0.20g, salt water absorption rateof the superabsorbent was69g/g. The salt water absorption rate was increased bynearly20g/g through the salt-resisting modification.4. Select PAA, CTS-g-PAA and cellulose superabsorbent(C-g-PAA) as theresearch object. The biodegradable performances of different types ofsuperabsorbents in soil were discussed. Observing the micrographs ofsuperabsorbents before and after biodegradation by scanning electron microscopy.The experiment results showed that cellulose and chitosan modified superabsorbentsprepared in this paper could biodegrade in soil. Under the same condition,biodegradation degrees of C-g-PAA and CTS-g-PAA were much higher than theproduct of PAA which was synthetic. SEM was used to observe the micrographs ofsuperabsorbents before and after biodegradation. The result showed that the surfacemorphology of the superabsorbent undergone great changes before and afterdegradation. Before the degradation, the surface of the superabsorbent was smoothand uniform; After the degradation, the surface structure of the superabsorbent wasuneven, appeared some ravines and holes. Under the condition of high magnification,could even observe the skeleton structure of undegrable part of the superabsorbent, indicating that some part of the superabsorbent composite has been degraded.