High-temperature solvent gradient liquid chromatography of model long chain branched polyethylenes

The high-temperature solvent gradient liquid chromatography system 1-decanol/1,2,4-trichlorobenzene/porous graphite HypercarbTM has been applied to the separation of well-defined model long chain branched (LCB) polyethylenes with different architectures (star, H-type, super H-type, pompom, comb). The model LCB polyethylenes have been prepared by anionic polymerization of butadiene followed by click chemistry. After hydrogenation of the polybutadienes, the LCB samples contain ∼ 2 mol % ethyl branches randomly distributed along the backbone and the LCB, as is typical for linear low density polyethylene (LLDPE). The results indicate that the LCB does not influence the chromatographic separation substantially. The adsorption characteristics of the LCB copolymers are dominated by the SCB content. The presence of LCB increases the molar mass of the samples; however, the increase in molar mass from 100 kg/mol to 200 kg/mol does not influence chromatographic separations in the applied system of porous carbon and 1-decanol/1,2,4-trichlorobenzene.