Non-equilibrium processes of interchain association induced by Cs+ ions in kappa-carrageenan aqueous solutions

摘要

We present preliminary results of the investigation of interchain association processes induced by Cs+ ions in kappa-carrageenan aqueous solution. The solutions contained variable amounts of NaI and CsI, under the condition that the total concentration of 1:1 electrolyte was 0.1 M. The associative processes were observed by static light scattering under isothermal conditions (at T = 25 degreesC), after cooling molecularly dispersed solutions obtained at high temperature (80 degreesC). It was found that, under all the investigated conditions of polymer concentration (from 0.2 to 2 g l(-1)) and ionic composition, the onset of time-dependent association fails to lead to an equilibrium, but proceeds up to physical gelation of the associating system. Depending on the experimental variables, however, the gelation threshold may take up to several days to be achieved. (C) 2004 Elsevier B.V. All rights reserved.