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13 C CP/MAS NMR study on alkali cellulose
Author(s) -
Yokota Hiromu,
Sei Toshiya,
Horii Fumitaka,
Kitamaru Ryozo
Publication year - 1990
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1990.070410325
Subject(s) - cellulose , alkali metal , microfibril , materials science , crystallography , nuclear magnetic resonance spectroscopy , nmr spectra database , phase (matter) , analytical chemistry (journal) , chemistry , spectral line , organic chemistry , physics , astronomy
The phase transition from cellulose to alkali cellulose (Na‐Cell) and the phase structure of Na‐Cell have been investigated by CP/MAS 13 CNMR spectroscopy. It has been found from the 13 CNMR spectra that both crystalline and noncrystalline components of cellulose decrease in resonance intensities in the transition process from cellulose to Na‐Cell I, suggesting that the noncrystalline and the crystalline regions of cellulose are converted to Na‐Cell simultaneously. The conversion model is considered as follows: The crystalline part imposes some restriction on the swelling of the noncrystalline part of cellulose, but the conversion of both parts to Na‐Cell may be possible when the swelling prevails in the whole microfibril as a result of the penetration of the alkaline solution into the crystalline part. Secondly, the 13 C spin‐lattice relaxation times ( T 1 ) have been measured to elucidate the phase structure of Na‐Cell. Though two T 1 values are obtained for each carbon of Na‐Cell except for C6 carbon, Na‐Cell has a homogeneous solid structure which is composed of the crystalline regions with a small heterogeneity.