AN EMPIRICAL-METHOD TO PREDICT THE LIQUID-LIQUID EQUILIBRIA OF BINARYPOLYMER SYSTEMS

An empirical method is described to predict the liquid-liquid equilibr ia of several binary systems of polymers in both polar and nonpolar so lvents according to a simple modification of the Flory-Huggins equatio n. The method hinges on a two-step procedure: (i) first, the UCST or t he LCST points are calculated by using a previous method proposed by t he author and based on the knowledge of a few pure-component propertie s only; (ii) second, starting from these points, all the miscibility g ap is calculated by applying a thermodynamic constraint and simple emp irical rules. The predicted results are in fair accordance with the ex perimental data in both the low- and high-temperature ranges. The corr elation of the hourglass phase diagrams is also considered.