Modeling of the phase equilibria of polyisobutylene in diisobutylketone with molecular mechanics

A method of calculating interaction parameters used in phase equilibrium ca lculations has been extended for predicting solvent activities of polymer s olutions. A pair of interaction parameters are determined by calculating in teraction energies between all pairs of molecules in the solution of intere st with a molecular mechanics method known as the consistent force field (C FF). The conformational space of a pair of molecules is sampled with a Mont e Carlo algorithm followed by energy minimizations. In this paper, the meth od is used to calculate interaction parameters and solvent activities for t he diisobutylketone/polyisobutylene system, using 2,2,4-trimethylpentane as a model compound for the polymer molecule. (C) 2000 Elsevier Science Ltd. All rights reserved.