Characterization of chemical composition distribution of ethylene-propylene-diene terpolymers by room temperature liquid adsorption chromatography and comparison to statistical approach

The chromatographic analysis of ethylene-propylene-diene (EPDM) terpolymers has hitherto been carried out only at high temperature, 120–160 °C. However, EPDM terpolymers are amorphous which could potentially allow to study their chromatographic behavior at room temperature (RT). To verify this hypothesis, cloud point measurements were realized to determine prospective solvent candidates. The identified solvents enabled injecting EPDM and model ethylene propylene norbornene terpolymers at RT. The retention of EPDM terpolymers on porous graphitic carbon (PGC) is a function at least two adsorbing comonomer components, ethylene and diene, in all tested chromatographic systems. This makes it difficult to characterize the chemical composition distribution (CCD) of terpolymers, which is of immense technical interest. Therefore, a modified form of LAC (LACm) was employed for determining the CCD of EPDM terpolymers using the identified solvents. Finally, the CCD obtained using different experimental methods was compared to the CCD determined using Monte Carlo simulations.