20 Years of polyolefin HPLC: Accomplishments and challenges

Published in: European Polymer Journal, Volume 200, 112491
Authors: Harald Pasch, Paul Eselem Bungu
November 2023
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Abstract:

The first publication on the interaction of polyolefins with stationary phases for high performance liquid chromatography at high temperatures (HT-HPLC) appeared in 2003. After the successful application of temperature rising elution fractionation and the introduction of crystallization fractionation for the analysis of polyolefins with regard to chemical composition this was a step towards methods for chemical composition analysis that are not based on crystallizability of the polyolefin. Polyolefins as semicrystalline polymers comprise crystallizable and amorphous components, and HT-HPLC opened the way to separate all sample components irrespective of their crystallizability. The first application of this new approach was the separation of ethylene–methyl methacrylate block copolymers, presented in 2005. The development of the first commercial HT-HPLC instrument and the discovery of graphitic materials as efficient stationary phases for HT-HPLC were further important milestones in the development of advanced separation techniques for complex polyolefins. The ultimate goal of comprehensively analyzing complex polyolefins by composition and molar mass was achieved by high temperature two-dimensional chromatography, which is based on the online coupling of HT-HPLC and HT-SEC. Further important developments include HT-HPLC using temperature gradients and the combination of solvent and temperature gradients. In this review, the most important developments in the field over the last 20 years are discussed, and different techniques, experimental protocols and some major applications are presented. In conclusion, challenges for future developments are outlined.