Study of the glass transition temperature and the mechanical properties of PET/modified silica nanocomposite by molecular dynamics simulation

摘要

In this study, the glass transition behavior and mechanical properties of polyethylene terephthalate) (PET), PET/silica nanocomposite and PET/hydroxylated silica nanocomposite were studied through molecular dynamics (MD) simulations. It was found that the density and the specific volume of PET, PET/silica nanocomposite and PET/hydroxylated silica nanocomposite regularly changed along with the changes of temperature and the transition occurs at the Tg point, the simulation results show the addition of nanosilica decreased Tg of PET in PET/silica nanocomposite, but the addition of hydroxylated silica increased Tg of PET in PET/hydroxylated silica nanocomposite,and the underlying mechanism resulting in the change of the glass transition temperature of nanocomposite was discussed. Moreover, the thermal and mechanical properties of the systems were characterized, The MD simulations showed that the addition of silica, particle increases Young's modulus, bulk modulus, Poisson's ratio, lame constants and compressibility of PET/silica nanocomposite in comparison with those in the pure PET system. (C) 2015 Elsevier Ltd. All rights reserved.