Prediction of polymer mixture compatibility by Monte Carlo simulation of intermolecular binary interactions

摘要

We have evaluated conformational and orientational averages of binaryinteraction integrals for pairs of chains constituting atomisticrepresentations of short polymer molecules. By considering A-A, B-B and A-Bpairs, we relate these results with the Flory-Huggins parameter for the A-Bmixtures. This parameter is commonly accepted as a good indicator ofcompatibility. Since the method ignores the simultaneous interactions withother molecules in the mixture, the local environment is approximatelydescribed by introducing an effective medium dielectric constant whose value isconveniently parameterized. The results for four different real systems arecompared with data obtained from experimental neutron scattering data. Themethod qualitatively predicts the sign and variation with temperature in thefour different cases, also showing a reasonable quantitative agreement in someof the cases. Its performance is discussed in comparison with a standard methodthat evaluates the Flory-Huggins parameter by calculating an average of theintermolecular energy of two molecules in contact, taking also into accounttheir off-lattice Flory-Huggins coordination numbers.