ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Diffusion of some homologous series of solutes [polyhydric alcohols, oligosaccharides, poly(ethylene oxide) polymers] has been studied in cellulose gels (〈20% w/w) and membranes (〈60% w/w) and the same materials when acetylated. It was found that (1) The molecular weight dependence of D approximates that for the solutes in water alone; the activation energies are also identical to the value for diffusion in pure solvent. (2) The presence of the cellulose chains reduces the rate of diffusion to a degree which is approximately given by the Mackie - Meares equation. (3) Exclusion is pronounced, particularly with the acetylated membranes, and gives a high degree of molecular size discrimination by a sieving mechanism. The membranes have a very narrow range of “pore” sizes, whereas the gels have a contrastingly broad distribution.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1981.070261216
Permalink