Separation and Characterization of Ethylene‐Propylene Copolymers by High‐Temperature Gradient HPLC Coupled to FTIR Spectroscopy

Abstract

Summary: The chromatographic separation of ethylene‐propylene (EP) copolymers with regard to chemical composition was accomplished by a new technique ‐ high‐ temperature gradient HPLC. Using a mobile phase of ethylene glycol monobutylether (EGMBE) and 1,2,4–trichlorobenzene (TCB), and silica gel as the stationary phase, copolymers with different ethylene contents were separated according to their chemical compositions. Using a sample solvent of n‐decanol and a column temperature of 140 °C, chromatographic conditions were established that correspond to separation in a precipitation‐redissolution mechanism. With the aim to obtain further information on the separation process, the HPLC system was coupled to FTIR spectroscopy through a LC‐Transform interface. The FTIR data confirmed that the copolymers were separated according to the ethylene content of the eluted samples.

Characterization of ethylene‐propylene copolymers with high‐temperature gradient adsorption liquid chromatography and CRYSTAF

“…36 Using this approach it was for the first time possible to separate ethylene-propylene (EP) copolymers according to their chemical composition. 45,46 However, there is still a significant influence of the molar mass on the separation, which makes it unpractical for routine analysis.…”

Recent Advances in High-Temperature Fractionation of Polyolefins

“…As was shown, for the first time blends of different polyolefins were separated quantitatively over a wide range of concentrations by liquid chromatography at 140 C. Moreover, EPC were separated into a propylene-rich part and an ethylene-rich part [153]. This chromatographic approach was also applied to the separation of EPC [55] and for the separation of various polyolefins with regard to the chemical composition of the components [154].…”

Advanced Separation Techniques for Polyolefins

“…Intensity (2800-3200cm [70][71][72]. The total polymer concentration is measured by the intensity of the CH 2 band, whereas the presence of CH 3 groups indicates branching and is characteristic of PP units.…”

“…[72]. It was subsequently used to develop a number of important methods for the separation of complex polyolefins.…”