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Vitrimeric Behavior Revealed by Fast Scanning Calorimetry in Branched Polyglycerol Networks Cross-Linked by Reversible Enamine Bonds

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Dynamic covalent bonds formed by enamine have played a crucial role in the development of vitrimers by enabling their rearrangement and reprocessability. In this study, polymer networks obtained by cross-linking a β-ketoester-functionalized branched polyglycerol (PG-βkest) with three different diamines, i.e. diaminopropane (DAP), 2,2′-(ethylenedioxy)bis(ethylamine) (EDO) and Jeffamine D230 (Jeff) were generated through enamine bond formation enabling the formation of materials with tunable glass transition temperatures ( T g ). A single, though broad, specific heat step was detected in all cases by conventional differential scanning calorimetry (DSC). However, by judiciously varying thermal protocols using fast scanning calorimetry (FSC), which permits heating/cooling rates as large as 1000 K s –1, we were able to separate and identify two distinct thermal events in the network composed by Jeff, used as a vitrimeric network model. Using Kissinger analysis, we conveyed information about the apparent activation energies of the two thermal events. In such a way, we were able to provide compelling evidence that the high-temperature event is due to a vitrimeric transformation ( T v ), while the low-temperature event exhibits all the features of a conventional glass transition.

Source: Macromolecules

DOI: 10.1021/acs.macromol.5c01560