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Investigation of Thermal Aging of Polyamide 4,6 by 1 H Solid‐State NMR
Author(s) -
Demco Dan E.,
Litvinov Victor M.,
Rata Gabriel,
Popescu Crisan,
Phan KimHô,
Schmidt Angelika,
Blümich Bernhard
Publication year - 2007
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200700095
Subject(s) - amorphous solid , polyamide , solid state nuclear magnetic resonance , phase (matter) , relaxation (psychology) , materials science , nmr spectra database , proton nmr , crystallography , chemistry , polymer chemistry , spectral line , nuclear magnetic resonance , organic chemistry , psychology , social psychology , physics , astronomy
The thermal aging of polyamide 4,6 was investigated by DSC, SEM, WAXS, and 1 H solid‐state NMR. Phase composition, chain mobility, morphology, and domain sizes were determined as a function of aging time. Proton transverse magnetization relaxation was measured at low resonance frequency, 1 H wide‐line NMR spectra and 1 H spin‐diffusion experiments were made at high resonance frequency. The NMR investigation shows that the aging process affects the rigid (crystalline), semi‐rigid (crystalline/amorphous interface), and the mobile (amorphous) fraction of polyamide 4,6. The amount of rigid (crystalline) fraction increases by about 10% upon aging at 200 °C for 1 000 h at the expense of the interfacial fraction. Chain mobility in crystalline phase is reduced upon aging suggesting perfections of the crystalline order.