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

TL;DR

This paper introduces a Monte Carlo simulation approach to predict polymer mixture compatibility by evaluating binary interaction integrals, relating them to the Flory-Huggins parameter, and comparing results with experimental data.

Contribution

The study presents a novel simulation method that estimates polymer compatibility through binary interactions, offering qualitative and some quantitative agreement with experiments.

Findings

Qualitatively predicts sign and temperature dependence of compatibility.

Shows reasonable quantitative agreement in some cases.

Compared favorably with standard Flory-Huggins based methods.

Abstract

We have evaluated conformational and orientational averages of binary interaction integrals for pairs of chains constituting atomistic representations of short polymer molecules. By considering A-A, B-B and A-B pairs, we relate these results with the Flory-Huggins parameter for the A-B mixtures. This parameter is commonly accepted as a good indicator of compatibility. Since the method ignores the simultaneous interactions with other molecules in the mixture, the local environment is approximately described by introducing an effective medium dielectric constant whose value is conveniently parameterized. The results for four different real systems are compared with data obtained from experimental neutron scattering data. The method qualitatively predicts the sign and variation with temperature in the four different cases, also showing a reasonable quantitative agreement in some of the cases. Its performance is discussed in comparison with a standard method that evaluates the Flory-Huggins parameter by calculating an average of the intermolecular energy of two molecules in contact, taking also into account their off-lattice Flory-Huggins coordination numbers.