Entanglement spacing variability in blends of narrow molecular weight distribution polystyrenes

Blends of monodisperse polystyrene were recovered from chloroform solutions and dried. Large variations in the mean entanglement molecular weight and in the zero shear viscosity were observed. The steady state compliance was dependent only on sample polydispersity and did not vary with sample history. The results could be rationalized using a modification of the theory of Kavassalis and Noolandi. It is concluded that the prior treatment of the polymers alterd the the entanglement spacing. This may be the result of a change in the spatial dimensions of the polymer moleculs in the bulk