Physicochemical processes occurring during the formation of cellulose diacetate membranes—research of criteria for optimizing membrane performance—III. Evaporation Rate And Equilibrium Phase Separation |
| |
Authors: | J. Vinit J.L. Halary C. Noel L. Monnerie |
| |
Affiliation: | Laboratoire de Physicochimie structurale et macromoléculaire, 10, rue Vauquelin 75231 Paris Cedex 05, France |
| |
Abstract: | The kinetics of acetone evaporation from films obtained by casting solutions of cellulose diacetate-acetone-water-inorganic additive have been analysed. Three successive regimes of evaporation have been identified. The first two are exponential and end, respectively, at critical times t1 and t2. Casting solution compositions have been determined both at the instant of phase separation (cloud point) and upon complete gelation. Also, the period of evaporation required to produce total film opacification has been measured for certain systems. These measurements have shown that time t1 corresponds to polymer precipitation at the film surface, and that time t2 corresponds to complete gelation of the medium. The results illustrate the effects of film thickness, casting temperature and “swelling” or “gelling” characteristics of the inorganic additive on times t1 and t2. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|