Separation of ethylene-norbornene copolymers using high performance liquid chromatography
Subrajeet Deshmukh1, Tibor Macko1, Jan-Hendrik Arndt1
1Fraunhofer Institute for Structural Durability and System Reliability, Division Plastics, Group Material Analysis, Schlossgartenstrasse 6, 64289 Darmstadt, Germany.
Journal of Chromatography. A
|July 11, 2021
Summary
Ethylene-norbornene (EN) copolymer elution behavior depends on norbornene content. Opposing trends observed suggest microstructure differences, confirmed by NMR spectroscopy and differential scanning calorimetry (DSC).
Area of Science:
- Polymer Chemistry
- Chromatography
Background:
- Ethylene-norbornene (EN) copolymers exhibit complex microstructures influenced by synthesis catalysts and norbornene content.
- Understanding these microstructures is crucial for predicting copolymer properties and applications.
Purpose of the Study:
- To investigate the elution behavior of ethylene-norbornene (EN) copolymers using porous graphite chromatography.
- To correlate elution volumes with average norbornene content and explore the impact of microstructure.
Main Methods:
- Utilized porous graphite (Hypercarb™) as the stationary phase in binary solvent gradient chromatography.
- Analyzed elution volumes of EN copolymers with varying norbornene content.
- Characterized copolymer microstructure using Nuclear Magnetic Resonance (NMR) spectroscopy and differential scanning calorimetry (DSC).
Main Results:
- Elution volumes of EN copolymers showed a correlation with their average norbornene content.
- A positive correlation was observed for copolymers with <20 mol% norbornene.
- A negative correlation was found for copolymers with >20 mol% norbornene.
Conclusions:
- The opposing trends in elution behavior are attributed to microstructural differences in EN copolymers.
- Norbornene content and catalyst system critically govern the microstructure and, consequently, the chromatographic elution.
- NMR and DSC data support the proposed link between microstructure and elution behavior.
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