Characterization Methods and Techniques 119
Figure 4.3X-ray diffraction spectra of
microcrystalline cellulose (Avicel
PH-101) shows three methods for
calculating Crl: (a) Segal method;
(b) peak deconvolution method; and
(c) amorphous subtraction method.
10 15 20 25
2 θ
30
(002)
(101) (021)
(a)
(10i)
|AM | 002
(040)
35 40
10 15 20 25
2 θ
30
(c)
35 40
10 15 20 25
2 θ
30
(b)
35 40
debranching and careful precipitation. Hemicelluloses can crystallize as hydrates and
the diffractogram will change depending upon the amount of moisture present. Other
studies have analyzed technical lignins for periodicity in their structure.
4.9.1.2 Cross-polarization/Magic Angle Spinning (CP/MAS)^13 CNMR
CP/MAS^13 C NMR or also often known as solid-state nuclear magnetic resonance
(ssNMR) can be used to observe changes of inter- and intramolecular hydrogen
