Advances in theory of equilibrium melting point depression in miscible polymer blends

The crystalline melting temperature of miscible polymer blends, consisting of a semi-crystalline and an amorphous polymer, is considered from a theoretical point of view. The depression of equilibrium melting temperature of the crystalline region is formulated. It is shown that the use of experimental melting temperatures in calculating interaction parameter between the two components could lead to erroneous results. Instead, the equilibrium melting temperatures are required, in conjunction with an equation of state model, to calculate the interaction energy and other thermodynamic properties of the mixtures. The advantages of equation of state model in this respect are highlighted. Results of theoretical prediction are compared with experimental data on equilibrium melting temperatures of miscible poly(methyl methacrylate)–poly(vinylidine fluoride) blends.