Molecular dynamics simulation of amorphous poly(ethylene terephthalate)

A conformational energy model has been set up for poly(ethylene terephthalate) (PET) for use in molecular dynamics simulations. The molecular dimensions, as expressed by the characteristic ratio, and the dipolar correlation factor of PET are key parameters in the simulations because they depend very differently on the conformational characteristics of the individual bond types in the chain. These parameters as well as the equation of state of the melt were emphasized in testing the model, and satisfactory representation was accomplished. It was found, however, difficult to achieve the experimental glass volume in MD cooling experiments below T-g. Packing features of bulk PET are discussed in terms of radial distribution functions. Dipolar correlation was found to be largely intramolecular in nature.