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Title: Crystallinity and perfection in ethylene vitrimers probed by combined calorimetry, scattering, and time-domain NMR
Author(s): Saalwächter, KayLook up in the Integrated Authority File of the German National Library
Somani, BhaskarLook up in the Integrated Authority File of the German National Library
Evans, Christopher M.
Issue Date: 2023
Type: Article
Language: English
Abstract: The kinetics of crystallization and crystal-crystal transformations in ethylene vitrimers are studied by time-domain NMR. These vitrimers previously exhibited polymorphic transition of crystal structures, which are shown here to be distinguishable by NMR via their dipolar line widths based upon different proton densities and fast internal motions. The conditions under which the polymorphs are formed and interconvert are identified via time-resolved NMR experiments, with a focus on recrystallization after full and partial melting. DSC experiments are used to clarify an unexpected superheating effect, which challenges the determination of actual melting points. We further identify a strong memory effect in isothermal (re)crystallization. Implications of the dynamic nature of the vitrimers in relation to the kinetics of crystallization are discussed. We find that internal perfecting of crystals, enabled by the vitrimeric exchange process, can have a large effect on the DSC-detected melting enthalpy without change in overall crystallinity.
Open Access: Open access publication
License: (CC BY 4.0) Creative Commons Attribution 4.0(CC BY 4.0) Creative Commons Attribution 4.0
Journal Title: Frontiers in soft matter
Publisher: Frontiers Media
Publisher Place: Lausanne
Volume: 3
Original Publication: 10.3389/frsfm.2023.1208777
Page Start: 1
Page End: 11
Appears in Collections:Open Access Publikationen der MLU

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