THERMODYNAMICS OF POLYMER BLENDS.

Abstract

Van der Waals already showed that spinodal and critical conditions can be used to derive parameters in equations of state. In the present paper this principle is applied to amorphous polymer blends and some recent experimental techniques are reviewed that are useful in this respect when dealing with such viscous mixtures. Various molecular models can be used to describe the observed phenomena. The classic Flory-Huggins lattice treatment cannot describe the experimental results. Some improvements of the lattice model are discussed. The now available data indicate a number of molecular parameters that, apart from the polymer MWD play an important role, viz. : the contact surface areas of the segments, the coil dimensions as a function of the state of the system and the free volume.