Influence of a glycerin additive on the structure and water vapor permeance of chitosan membranes

In this study, the role of glycerin as an additive in the preparation of chitosan membranes was investigated with respect to their structure and water vapor permeance. The modified chitosan membranes were systemati- cally characterized using scanning electron microscopy, thermogravimetric analysis, Fourier Transform infrared spectroscopy, and X-ray diffraction; the observations showed that the addition and removal of glycerin did not obviously influence the surface morphology or thermal stability of the chitosan membranes. Furthermore, water vapor sorption experiments revealed that the equilibrium water content in the modified chitosan membranes was increased slightly as compared to that in the pure chitosan membrane. The addition and removal of glyc- erin impacted the water vapor permeance of the chitosan membranes. When the glycerin content exceeded 80 wt%, the water vapor permeance of the composite membranes was higher than that of the pure chitosan membrane.