Studies of the water permeability and mechanical properties of a film made of an Ethyl Cellulose-Ethanol-Water ternary mixture

Abstract

ABSTRACT:A water permeability study of ethyl cellulose (EC) film made from an EC-ethanol-water ternary mixture is presented. EC films were prepared by pouring the solution onto a polycarbonate plate and by spraying. The results reveal that the permeability of water, estimated by diffusion experiments, increases as the amount of the nonsolvent increases in the liquid-liquid demixing process. In addition, a relative decrease in the evaporation rate of ethanol compared to that of water following an increase in casting temperature or a higher EC concentration produces a membrane with lower permeability. A mechanical evaluation of the films is also presented. Addition of water to the solvent leads to decreases in the modulus of elasticity, stress, and elongation, due to changes in the morphology of the film. The surface of the film was visualized by SEM photomicrography.

Soft Gelatin Films Modified with Cellulose Acetate Phthalate Pseudolatex Dispersion—Structure and Permeability

“…The permeability of the tritium-labeled water through the films at 37 °C was studied. The tested film sample was placed between the donor and the acceptor chambers of a vertical diffusion cell [19,20]. The permeation area was 1.77 cm 2 .…”

Novel Method for Visualizing Water Transport Through Phase-Separated Polymer Films

“…Below the percolation threshold, HPC exists mainly as inclusions in the EC matrix. However, sprayed films of EC have finite low water permeability (Hjärtstam & Hjertberg, 1999). Hence, water transport through the EC matrix and HPC domains can occur, and this likely caused the "pinhead" droplets.…”

“…In these studies, the critical HPC fraction between 22 and 24% was suggested to be associated with a percolation threshold for the HPC domains in the film. As pure EC has low water permeability (Hjärtstam & Hjertberg, 1999), water transport takes place predominantly through the HPC phase.…”

A G-Band (140–220 GHz) planar stubbed branch-line balun in BCB technology

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