Temperature dependent in situ characterization of reversible polymerisations
Polymers capable of dynamic bonding/debonding reactions are of great interest for potential applications as self-healing materials or printable networks. Since temperature is often used as a stimulus for triggering reversible bonding reactions, analysis at elevated temperatures is very useful for the in situ investigation of the reaction mechanism because unwanted side effects can be minimized when performing the analyses at the same temperature as that at which the reactions occur. For investigating the kinetics of retro Diels-Alder based depolymerization of Diels-Alder polymers a high temperature size exclusion chromatographic (SEC) system was optimized and the temperature dependent SEC (60-150 °C) was recently established in our group. The changing molecular weight distribution of the analyzed polymers during depolymerization gives valuable quantitative information on the kinetics of the reactions.
The SEC system and column material stability are optimized and tested using thermoanalysis methods, infrared spectroscopy, physisorption and scanning electron microscopy. The development of adequate interpretation methods is essential for the correct evaluation of the chromatograms. Complementary methods as temperature dynamic light scattering, thermogravimetric analysis, and time resolved nuclear magnetic resonance spectroscopy at high temperatures are supporting our investigations.
This work is a subject of an active collaboration with Evonik Industries and the group of Christopher Barner-Kowollik, KIT.
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