Modeling of Phase Separation in Polymer Solutions during Polymeric Gel Formation

The phase equilibrium in a polymer gel consisting of two phases, of which one involves the polymer network formed through crosslinking of polymer chains (gel-phase of the material) and the other represents a solution of noncrosslinked polymer chains in the mixture of low-molecular fluids is studied. In this work, a model capable of describing the phase separation in the polymer gel at the stage of its formation is proposed. The model takes into account the original composition of solution, the degree of polymerization of polymer chains at the moment of their attachment to the gel-phase, the change in the volume of a polymer network as it swells, the variation in the length of the statistic segment of a polymer chain (Khuns segment) as the mixture composition changes.