PET/PEN blends of industrial interest as barrier materials. Part 1. Many-scale molecular modeling of PET/PEN blends

Mesoscale molecular simulations, based on parameters obtained through atomistic molecular dynamics and Monte Carlo calculations, have been used for modeling and predicting the behavior of PET/PEN blends. Different simulations have been performed in order to study and compare pure homopolymer blends with blends characterized by the presence of PET/PEN block copolymers acting as compatibilizer. A many-scale molecular modeling strategy was devised to evaluate PET/PEN blend characteristics, simulate phase segregation in pure PET/PEN blends, and demonstrate the improvement of miscibility due to the presence of the transesterification reaction products. The behavior of distribution densities and order parameters of the compatibilized blends demonstrates that mixing properties improve significantly, in agreement with experimental evidences. Barrier properties such as oxygen diffusivity and permeability have also been evaluated by finite element simulations. Accordingly, many-scale modeling seems to be a successful way to estimate PET/PEN blend properties and behavior upon different concentrations and processing conditions. (c) 2006 Elsevier Ltd. All rights reserved.