Nonsolvent Effects on Morphology of Cellulose Acetate Films Prepared by Dry-Cast Process

Abstract

Cellulose acetate (CA) porous films were prepared by a dry-cast process from CA/acetone/nonsolvent systems. Isopropanol, ethanol, and water were used as the nonsolvents and their effects on the formation of the porous structure of the CA matrix were investigated. As acetone evaporated from the solution, the mass ratios of both CA and the nonsolvent increased, finally inducing a porous structure in the film via phase separation. Scanning electron microscopy showed that the morphology of the CA films could be significantly altered by adjusting the content of the nonsolvent in a certain range, while tensile strength and porosity of the films obtained from the solutions correlated well with the nonsolvent content, the former decreases but the latter increases with an increase in the nonsolvent dosage.

Keywords:

• cellulose acetate
• dry-cast process
• film casting
• phase separation
• porous membranes

Acknowledgments

This work was supported by the National Natural Science Foundation of China (nos. 50872124 and 51003096) and the Zhejiang Sci-Tech University Research Program (nos. 111129A4Y10804 and 11112732611021).