PET/PEN Blends of Industrial Interest as Barrier Materials. Part I. Many-Scale Molecular Modeling of PET/PEN Blends

esoscale mol. simulations, based on parameters obtained through atomistic mol. dynamics and Monte Carlo calcns., were 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 mol. 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 exptl. 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 est. PET/PEN blend properties and behavior upon different concns. and processing conditions.