Phase Transitions and Thermodynamic Interaction Parameters of Components in Poly(methyl methacrylate) and Poly(vinyl acetate)

Phase diagrams with UCST are constructed for systems poly(methyl methacrylate)-butanol, poly(vinyl acetate)-methanol, and poly(vinyl acetate)-2-propanol. The boundary curve of the PMMA-o-xylene system is unusual in shape, which is explained by the fact that polymer macromolecules form stereo complexes that appear during solution cooling. The thermodynamic interaction parameters chi of components and the values of chi(cr) and critical concentration of the systems under study are calculated. With increasing temperature the value of chi decreases, which indicates that the interaction of components is improved under heating and agrees with the phase diagrams of the systems.