Studies On The Preparation Of A Quaternary Ammonium Salt Of Chitosan And The Permeability Of Gases In Its Film

In this paper, a quaternary ammonium salt of chitosan was synthesized and the factors affect on the solubility or degree of substitution (DS) of product, such as the concentration of alkali, the time of basification, the content of water in system, the time of dispersing and the method of adding epoxyproryltrimethylammonium chloride, were discussed in detail. The product was characterized by IR, DSC, TG and X-RAY diffraction. The effects of time, humidity and temperature on the gases permeability of the quaternary ammonium salt of chitosan film were researched. The result shows:1. With the increasing of the concentration of alkali, the content of insolubility of the product reduces initially but increases later, the DS of product increases initially then reduces later. The product has good solubility and high DS at 10% content of alkali. The insoluble product reduces at initially and then keeps stability later with the time of basification extending. With the increasing of the content of water in system, theinsolubility of the product reduces initially and then increases later. The product has good solubility at the 7% content of water. With the extending of the dispersing time, the insoluble product reduces, and the DS of product increases. The product has good solubility when dripping epoxyproryltrimethylammonium chloride more times.2. Comparing the IR, DSC, TG and X-Ray between the primary chitosan and the product, the results showed that the product is the quaternary ammonium salt of chitosan, the thermo stability and the degree of crystal reduce after reacting.3. With the extending of the time, the permeability of CO2 reduces rapidly initially and then keeps stability later, but the permeability of O2 and H2O keeps stability. The order of the permeability of gases is PH2a > PCO2 > PO2 . With the increasing of the humidity, the permeability of CO2 and O2 reduces, but the permeability of H2O does not have obvious change. When the humidity is higher than 60%, the permeability of CO2 and O2 increases rapidly and the permeability of H2O reduces gradually. With the increasing of the temperature, the permeability of H2O and O2 increases gradually, but the permeability of CO2 increases initially and then keeps stability later.