Anomalous mixing behavior of polyisobutylene/polypropylene blends: Molecular dynamics simulation study

Molecular dynamic (MD) simulations were used to analyze the unusual mixing behavior of polyisobutylene (PIB) with head-to-head (hh) and head-to-tail polypropylene (PP). With the help of an atom model, the heat of mixing and the Flory parameters were computed from MD simulations. Random phase approximation in analogy with neutron scattering (SANS) experiments indicated the Flory parameters from the structure factors. It was found that at high molecular weight, the isotactic PP/PIB blend was immiscible, as indicated by the MD similations.