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

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.