TY - JOUR
T1 - Correlations of apparent cellulose crystallinity determined by XRD, NMR, IR, Raman, and SFG methods
AU - Lee, Christopher
AU - Dazen, Kevin
AU - Kafle, Kabindra
AU - Moore, Andrew
AU - Johnson, David K.
AU - Park, Sunkyu
AU - Kim, Seong H.
N1 - Funding Information:
This work was supported by the Center for Lignocellulose Structure and Formation (CLSF), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences under Award Number DE-SC0001090. This work was also supported by Subcontract No. XGB-3-23024-01 with the National Renewable Energy Laboratory (NREL), under Contract No. DE-AC36-08-GO28308 with the U.S. Department of Energy. Sample preparation and XRD and NMR data collection were carried out with funding from the NREL. IR, Raman, and SFG analyses as well as XRD simulation and data analyses were carried out with CLSF support.
Publisher Copyright:
© Springer International Publishing Switzerland 2015.
PY - 2015
Y1 - 2015
N2 - Although the cellulose crystallinity index (CI) is used widely, its limitations have not been adequately described. In this study, the CI values of a set of reference samples were determined from X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and infrared (IR), Raman, and vibrational sum frequency generation (SFG) spectroscopies. The intensities of certain crystalline peaks in IR, Raman, and SFG spectra positively correlated with the amount of crystalline cellulose in the sample, but the correlation with XRD was nonlinear as a result of fundamental differences in detection sensitivity to crystalline cellulose and improper baseline corrections for amorphous contributions. It is demonstrated that the intensity and shape of the XRD signal is affected by both the amount of crystalline cellulose and crystal size, which makes XRD analysis complicated. It is clear that the methods investigated show the same qualitative trends for samples, but the absolute CI values differ depending on the determination method. This clearly indicates that the CI, as estimated by different methods, is not an absolute value and that for a given set of samples the CI values can be compared only as a qualitative measure.
AB - Although the cellulose crystallinity index (CI) is used widely, its limitations have not been adequately described. In this study, the CI values of a set of reference samples were determined from X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and infrared (IR), Raman, and vibrational sum frequency generation (SFG) spectroscopies. The intensities of certain crystalline peaks in IR, Raman, and SFG spectra positively correlated with the amount of crystalline cellulose in the sample, but the correlation with XRD was nonlinear as a result of fundamental differences in detection sensitivity to crystalline cellulose and improper baseline corrections for amorphous contributions. It is demonstrated that the intensity and shape of the XRD signal is affected by both the amount of crystalline cellulose and crystal size, which makes XRD analysis complicated. It is clear that the methods investigated show the same qualitative trends for samples, but the absolute CI values differ depending on the determination method. This clearly indicates that the CI, as estimated by different methods, is not an absolute value and that for a given set of samples the CI values can be compared only as a qualitative measure.
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U2 - 10.1007/12_2015_320
DO - 10.1007/12_2015_320
M3 - Article
AN - SCOPUS:84944471738
SN - 0065-3195
VL - 271
SP - 115
EP - 131
JO - Advances in Polymer Science
JF - Advances in Polymer Science
ER -