Polymer and Materials Science
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Measurements of preferential adsorption, λ(ν), by differential refractometry, and of swelling equilibrium, ν3-, of polydimethylsiloxane (PDMS) networks were carried out in the solvent mixture ethyl methyl ketone (MEK) + cyclohexane (Ch), at 25°C. The preferential adsorption and the total sorption were also determined, by light scattering, for linear PDMS in the same mixed solvent. The behaviour of the system crosslinked PDMS/MEK + Ch is compared with that of the system linear PDMS (dilute solution)/MEK + Ch. The experimental values of ν3 and λ are compared with those predicted by thermodynamic theory. For this comparison, new thermodynamic equations, to calculate preferential and total sorption at finite polymer concentration, are derived using the extended Flory-Huggins model. The derived equations take into account the solvent composition dependence of interaction parameters, neglected (as an approximation) in previous works.
Type of Medium: