Dynamics in Crystallites of Poly(ε-caprolactone) As Investigated by Solid-State NMR

Autor:	Ruth Bärenwald, Anja Achilles, Kay Saalwächter, Christiane Hackel, Kerstin Schäler
Rok vydání:	2013
Předmět:	Polymers and Plastics Chemistry Organic Chemistry Inorganic Chemistry Crystallography chemistry.chemical_compound Microsecond Molecular dynamics Solid-state nuclear magnetic resonance Chemical physics Phase (matter) Materials Chemistry Crystallite Methylene Anisotropy Caprolactone
Zdroj:	Macromolecules. 46:7818-7825
ISSN:	1520-5835 0024-9297
DOI:	10.1021/ma401532v
Popis:	We investigate the molecular dynamics within the crystallites of poly(e-caprolactone), PCL, crystallized from the melt by means of high-field 13C and low-field 1H NMR spectroscopy, addressing the question of whether it can be classified as a “crystal-fixed” polymer without chain motion through the crystallites. We address fast, slow, and intermediate-regime (microseconds to milliseconds time scale) motions by means of high-resolution of 13C DIPSHIFT and CODEX MAS experiments as well as low-resolution static 1H FID and MSE measurements over a range of temperatures. The DIPSHIFT data provide information on motionally averaged 13C–1H dipole–dipole couplings and indicate the presence of fast (≤1 μs) methylene group librational motions within the crystalline phase, where the amplitudes increase with increasing distance from the rather rigid ester groups. The CODEX experiments, addressing slow (≥ms) local rotations of the chemical-shift anisotropy tensors, suggest the absence of slow intracrystallite chain dyna...
Databáze:	OpenAIRE
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