The Study On Interface Performance Of Chitosan Fresh-Keeping Membrane

In this paper, the interface characteristic of coated film of chitosan was studied, including the wetting performance, the stability and the antibacterial performance. In addition to, the molecular structural state of chitosan membrane surface and its influence on interface characteristic were also studied.1. The wetting ability of chitosan solution on the olefin medium was poor and the contact angle between chitosan solution and olefin was 105°. Through the work of filtration, the wetting agent Tween-20 was founded to have best wetting performance and the most excellent applying method was worked out. The results showed: When 0.02% Tween-20 was added to 2.0% chitosan solution, the contact angle decreased to 52°, the surface tension of chitosan solution declined from 63. 7dyn/cm to 39. 1 dyn/cm, the critical surface tension of chitosan membrane was enhanced from 40.0KJ/m~2 to 62.8KJ/m~2.2. When glutaraldehyde or glycerol was added to chitosan solution, which would be formed chitosan membrane, the crystallization of chitosan membrane was depressed and the stability was enhanced. The suitable amount is 30mg glutaraldehyde being added to 1000mg chitosan or 500mg glycerol being added to 1000mg chitosan. The result of XRD indicated that the area of main cryatallization apex declined 52.6% or 47.8%.3. Some kinds of bacterium were separated from semi-tropical fruits and the antibacterial performance of chitosan membrane to these bacteriums was studied. In addition to, the relationship between the antibacterial performance and molecular structure of various chitosan ramifications was studied through IR. Some results have been obtained. Firstly, the antibacterial effects can be enhanced while the concentration of chitosan solution was enlarged, the antibacterial effects arrived at best point when the concentration was 1.2% and remained stable when the concentration was increased from 1.2% to 2.0%. Secondly, the molecular weight of chitosan affected the antibacterial effects and could change antibacterial mechanism. Finally, the antibacterial effects of Carboxymethyl chitosan and quaternary ammonium salt of chitosan were more excellent than chitosan. The antibacterial effects of chitosan were a little better than chitosan crosslinked by glutaraldehyde. The conclusion of IR demonstrated that the more excellent antibacterial...