Solvent Selection for Liquid Adsorption Chromatography of Ethylene–Propylene–Diene Terpolymers by Combining Structure–Retention Relationships and Hansen Solubility Parameters

Liquid adsorption chromatography (LAC) of polyolefins has seen a remarkable growth since its inception, but studies focusing on the polyolefin elastomer ethylene–propylene–diene (EPDM) terpolymer are rare. In this study, LAC of EPDM terpolymers was carried out using porous graphitic carbon (Hypercarb) as the stationary phase and investigating benzene derivatives as components of the mobile phase. Structure–retention relationships (SRRs) were elaborated for several substituted aromatic solvents, which were classified as either adsorption (adsorli) or desorption (desorli) promoting. Subsequently, by combining the SRRs with a simplified form of the Hansen solubility parameters, a predictive tool for solvent selection in LAC of EPDM was created. Using this approach, for the first time, new nonchlorinated desorlis were identified, namely, tetralin and 1,2,4-trimethylbenzene instead of the widely used chlorinated aromatic desorlis 1,2,4-trichlorobenzene and 1,2-dichlorobenzene. This also enabled an improvement in the chromatographic resolution of EPDM terpolymers.