POLYMER-POLYMER INTERACTION PARAMETERS BY INVERSE GAS-CHROMATOGRAPHY - A NOVEL MOLECULAR INTERPRETATION OF NONRANDOM PARTITIONING OF SOLVENT PROBES IN POLYMER BLENDS

Non-random partitioning of molecular probes in a polymeric mixture was examined with Kirkwood-Buff-Zimm (KBZ) cluster integrals. Equations w ere derived to give relationships of thermodynamic quantities that can be obtained by using inverse gas chromatography (IGC). The mer-mer co rrelation structure factor S-(AB)(0) in a binary mixture of polymers A and B in terms of the spatial distribution of a probe, S, around a m olecule A and a molecule B is discussed. The derivation allows a direc t assessment of the correlation structure factor obtained either from scattering experiments or from IGC measurements. The common polymer-po lymer interaction parameter from the two types of experiments is discu ssed with respect to criticism concerning IGC. The detailed molecular description of the probe behavior in a polymeric mixture at infinite d ilution of the probe given in this work can be used in IGC studies of the microstructure of polymer mixtures or other mixtures of liquids. I n order to illustrate our approach, the structure factor and the inter action parameter of the blends of polystyrene (A) and poly(butyl metha crylate) (B) were evaluated using IGC results of DiPaola-Baranyi and D egre.