SWELLING AND COLLAPSE OF POLYMER NETWORKS IN POLYMER-SOLUTION

Thermodynamics of swelling of polymer networks in solution or in melt of another polymer has been theoretically analysed. Interaction of components is taken into account in the framework of the Flory-Huggins approximation. For networks prepared in the presence of excess of a solvent the jump-like transition from swelling of rather long chains in the athermal melt to the segregation of components with increase of the incompatibility parameter proceeds. For swelling of a network in a polymer solution there exist such swelling regimes when the increase of the polymer concentration in the external solution a network first decreases its dimensions and transits into the globular state and then proceeds the jump-like unfolding with sharp increase of the concentration of a linear polymer inside a network.