Determination of interaction parameters of block copolymers containing aromatic polyesters from solubility parameters obtained from solution viscosities

Flory–Huggins interaction parameters of polymeric systems including polysulfone and aromatic poly(ester imides) were calculated using solubility parameters in order to estimate the tendency of phase separation of the respective block copolymers. The scope of the work was to compare χ values based on δ calculated by means of increment tables as well as obtained experimentally using the solubility behavior in different solvent mixtures. It was found that χ parameters based on experimentally determined δ are generally at least 1 order of magnitude smaller than values calculated with increment tables. However, the experimental data sets for χ allowed the establishment of a general order of phase separation in the block copolymers investigated almost independently of the method of obtaining the solubility parameters (i.e., from the increment table used). The tendency of phase separation correlates with the tendency found by investigation of the respective block copolymers.