Authors: Mustafa GENÇASLAN, Mustafa KESKİN, Paul H. E. MEIJER
Abstract: We introduce a model which combines the two-component lattice gas model [1-3] with the Flory-Huggins theory  in order to study the critical behaviour of mixtures of polymers. This new model is similar to the Tompa model , except that one can deal with two polymers instead of one. In the model, we introduce two Flory chain length parameters in order to describe polymer mixtures in the presence of their vapor phase. The model can also be applied to a ternary mixture consisting of two polymers in a common solvent. The conditions under which the critical line becomes self-crossing are given and an explicit expression is evaluated for the coordinates of this point. The critical lines are displayed in the density-density and pressure-temperature (P-T) planes for the right corner case. P-T diagrams are discussed according to Scott and van Konynenburg binary gas-liquid phase diagram classification .