Study On Preparation, Structure And Properties Of A Modified Chitosan Hydrogel

Aiming at the problems of adding additives as chemical cross-linked agents when gels were prepared and hard separating and purifying the gels, the modified chitosan hydrogel was prepared without any chemical cross-linked agents by one pot; the influences of reacting time and materials ratio on molecular weight and degree of substitute (DS) of the quaternized chitosan were discussed; the structure of the hydrogel was characterized by IR and SEM. The properties of water-solubility, moisture-absorption, moisture-retention, mechanics and antibacterial were studied; in addition, the applications of the hydrogel on drug-releasing were studied. The results showed that:1. Increasing the reacting time and percent of 2,3-epoxyproryltrimethyl ammonium chloride (EPTMAC), the degree of substitute of the quaternized chitosan increased; With the increasing of reacting time the molecular weight decreased but increased when percent of EPTMAC increased.2. The hydrogel we got was cross-linked by the interactions of polymer chain and electrostatic effect between ammonium group and -OH which was negative on the polymer chains.3. The modified chitosan hydrogel swelled rapidly in pure water; The water swelling degree of the hydrogel decreased when reacting time and percent of EPTMAC increased; The maximal swelling degree first increased then decreased as reacting time increased, but decreased with the increasing of percent of EPTMAC.4. The dried modified chitosan hydrogel absorbed moisture quickly, The moisture-absorption of the hydrogel decreased when the percent of EPTMAC and reacting time increased; The abilities of moisture retention increased as the percent of EPTMAC and reacting time increased.5. The stress and strain of the modified chitosan hydrogel increased when the percent of EPTMAC and reacting time increased, while the breaking elongation decreased. The ability of stress resisting was enhanced, while plastic ability was weakened.6. The modified chitosan hydrogel had antibacterial properties on Staphylococcus aurous and Penicillium. With the percent of EPTMAC and reacting time increasing, the inhibitory effect of the hydrogel increased. The antibacterial abilities of the hydrogel improved after absorbing Dimethyl Fumarate (DMF).7. The DMF-absorption of the modified chitosan hydrogel decreased as the percent of EPTMAC and reacting time increased. The drug-releasing ratio of the hydrogel decreased while the percent of EPTMAC and reacting time increased; in alkaline condition, the drug-releasing ratio is higher than it was in acidic and neutral condition.The results of this paper provided a referenced method on simplifying the preparation techniques of hydrogels, and they also provided references to researches of drug-carried hydrogels and applications of the hydrogel.