Predicting Solubility of Isotactic Poly (1-Butene) in Different Organic Solvents by Modified UNIQUAC Model

The UNIQUAC activity coefficient model is extended to predict solid-liquid equilibrium of isotactic crystalline poly (1-butene), iPBu-1, in different organic solvents. The UNIQUAC activity coefficient model used in this work is based on the concept of group contribution and consists of combinatorial, residual and free volume terms. To account for branching of atom groups in the monomer structure of the polymer, a correction factor has been applied to the surface parameter of combinatorial and residual terms. Use of this correction factor has significantly improved the accuracy of the model and shows that the proposed activity coefficient model is a proper model for solid-liquid equilibrium calculation in polymer solutions.