Estimation of the Binding Energy in Random Poly(Butylene terephtalate-co-thiodiethylene terephtalate) Copolyesters/Clay Nanocomposites via Molecular Simulation

Abstract

Molecular mechanics/dynamics computer simulations are used to explore the atomic scale structure and to predict binding energy values for polymer/clay nanocomposites based on random poly(butylene terephtalate-co-thiodiethylene terephtalate) copolyesters, montmorillonite and several, different organic surfactant. Our results reveal that the energy of binding between the polymeric matrix and the montmorillonite platelet shows a decreasing trend with increasing molecular volume, V, of the organic compounds used as surfactant, and that the substitution of hydrogen atoms with a –SH moiety in the organic molecules results in progressively increasing interaction of the surfactant with the copolymer, as the sulfur-containing comonomer concentration is increased. Finally, under the hypothesis that the clay platelets are uniformly dispersed within the polymer matrix, the pristine clay still yields a high interfacial strength between MMT and copolymers.