Barrier properties of small gas molecules in amorphous cis-1,4-polybutadiene estimated by simulation

Abstract

The solubility and diffusivity of small gas molecules in amorphous cis-1,4-polybutadiene were estimated in the temperature range 250–400 K, using both molecular dynamics simulations and the transition state theory implementation of the Widom insertion method. A comparison of the methods is given and the results obtained are compared with available experimental data. The accuracy in predicting diffusion and solubility coefficients of a range of small gas molecules in an amorphous polymer of both methods is good when compared to experimental values. The effects of the temperature and the models size are also examined. Selectivity to oxygen and nitrogen are estimated for the various models studied as well. This work shows the potential of computational methods for the prediction of physical properties of industrial importance like selectivity.