Softener absorption by regenerated cellulose. Uptake from 10% aqueous glycerol

Abstract

AbstractThe softener content of regenerated cellulose film (gel film) in equilibrium with aqueous glycerol solution was found to be determined primarily by only two factors: the softener concentration of the solution and the volume of free space within the gel film. Volume changes of film in contact with 10% glycerol solutions are negligible. Preferential uptake of glycerol as the solution passes into the film is, at most, slight, amounting to no more than 0.04% at the concentration used. No evidence was found for a large enrichment within the gel film, as has been postulated, or for adsorption of glycerol on cellulose chains. The system, cellulose‐glycerol‐water, appears to be a polymer‐liquid mixture brought to equilibrium principally by diffusion. It appears that at 10% concentration, glycerol and probably other organic compounds are taken in by gel film by a diffusion process in which the free water in the film is replaced by solution without appreciable enrichment or change in volume. Water contained in the interchain spaces of cellulose is simply exchanged for softener solution. The free volume of the film as determined by the cellulose structure and the degree of crystallinity remains essentially unchanged on softener uptake at the softener concentration studied.