Morphological and structural formation of the regenerated cellulose membranes recovered from its cuprammonium solution using aqueous sulfuric acid
✍ Scribed by Tomoko Hongo(nee Hirasaki); Miki Inamoto; Michitaka Iwata; Toshihiko Matsui; Kunihiko Okajima
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 369 KB
- Volume
- 72
- Category
- Article
- ISSN
- 0021-8995
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✦ Synopsis
Morphological and structural formation of the regenerated cellulose membranes from its cuprammonium hydroxide solution by acid coagulation was investigated. Scanning electron microscopic observation revealed that the morphology of the membranes changed drastically as functions of both the cellulose concentration in the original cellulose solution C Cell and the concentration of sulfuric acid as a coagulant C H2SO4 . It was found that at a constant polymer concentration (8 wt %) the membrane prepared by using 5 wt % aqueous sulfuric acid exhibits higher water flux, far smaller swelling anisotropy parameter L t , and larger porosity P r with a thinner skin structure, and these parameters were proven to be associated with lower (11 0) crystal plane orientation coefficient f (11 0) compared with those for the membranes obtained by aqueous sulfuric acid with more than 10 wt %. On the other hand, at constant coagulant concentration (10 wt %) the membrane prepared by using the polymer solution with 5 wt % shows far greater P r with practically no distinct skin structure; hence, a higher flux. The drastic changes in the morphology and structural parameters as functions of C Cell and C H2SO4 were found to be well correlated with abrupt changes in material transportation (copper ion, ammonium ion, and water) from the polymer solution to aqueous coagulants as a function of C Cell and C H2SO4 .