Characterization of rubber-solvent interaction by inverse gas-chromatography

The interaction between various structured hydrocarbons and nonpolar types of rubber (EPDM, NR, 1,2-BR, cis-BR and SBR) was studied by Inverse Gas-Chromatography (IGC) in a temperature range of process-technological relevance. The information contained in the specific retention volumes led to a quantitative characterization of the systems. The solvent quality of the alkanes improved in each of the rubbers studied as the number of C atoms increased. Because of their high contribution to mixing entropy cyclic hydrocarbons have the best solvent properties. Aromatic structures in EPDM make only a small additional contribution to the mixing free energy. The thermodynamic solvent quality experiences a steady improvement as the delta parameter of the rubbers rises. In the temperature range studied, the higher the number of C atoms, the better the interaction between alkanes and covalent types of rubber.