Infrared spectra of the crystalline modifications of cellulose

Abstract

The bands due to stretching of OH groups of all four crystalline modifications of cellulose have been measured using a deuteration technique which enables crystalline regions to be studied independently of amorphous regions. Cellulose III prepared from cellulose I (IIII) was found to be different from cellulose III prepared from cellulose II (IIIII). Similarly different cellulose IV's were obtained from celluloses I and II (IVI and IVII). However, the infrared spectra suggest that only one of these, namely, IIII should be regarded as having a crystal structure distinctively different from those of cellulose I and II. Thus IVI and IIIII closely resemble celluloses I and II, respectively, while IVII shows a diffuse absorption and may well possess a disordered lattice. The bearing of these results on the crystal structures of celluloses I and II is discussed. The unit cells of celluloses IIIII and II are different, although their infrared spectra are very similar. These facts suggest that hydrogen bonding in these two forms is of the layer type in the (101) plane, though the possibility of hydrogen bonding in the (101) plane cannot be entirely eliminated.

Polarized infrared microspectroscopy of single spruce fibers: Hydrogen bonding in wood polymers

“…22 By contrast, water molecules can be inserted in noncrystalline regions of cellulose and at accessible crystal surfaces and interfaces where the crystalline cellulose network is disrupted. 21,22,27 Thus, it is possible to distinguish the hydroxyl groups of inaccessible cellulose fibrils from those of accessible cellulose surface chains and amorphous cellulose 12 and presumably from hydroxyl groups of the less ordered or amorphous hemicelluloses-lignin matrix. 41 The average PM dichroic spectrum of three single fiber measurements in liquid D 2 O is shown in Figure 5.…”

“…30 This method has been employed in studies on cellulose to distinguish between the different hydroxyl groups and their respective orientation and to explore possible hydrogen bonding patterns. 13,14,16,25 Deuteration techniques, 12,21,27 also in conjunction with polarized light, 22,26 have been utilized to assess the accessibility of hydroxyl groups and to distinguish amorphous and crystalline domains in cellulose. Second derivative 15,19 and deconvolution 17,18 processing of cellulose spectra have also resulted in a better resolution of O-H stretching bands.…”

Fourier Transform Infrared Spectroscopy for Natural Fibres

“…IR was firstly used to investigate hydrogen bonds in cellulose in the 1950s [e.g. [20][21][22] and then the whole area of OH stretching wave-number in IR spectra for cellulose I and cellulose II [23][24]. The OH stretching region always covers 3-4 sub-peaks and these sub-peaks cannot be determined in the original data set.…”

Tools for Cellulose Analysis in Plant Cell Walls

“…Simultaneous to the development of XRD methods, Rowen et al (1947) analyzed cellulose from cotton (Gossypium hirsutum) by infrared (IR) absorption spec-troscopy, and later, Marrinan and Mann (1956) recognized that algae (Valonia) and bacterial cellulose yielded IR spectra that were different from those of tunicates, cotton, or ramie (Boehmeria nivea). Eventually, in the early 1980s, the spectroscopic technique of solid-state 13 C cross-polarization magic-angle spinning NMR spectroscopy was able to resolve this issue by showing that native cellulose I diffraction data from many natural sources were a composite of diffraction from the two crystalline allomorphs Ia (triclinic unit cell) and Ib (monoclinic unit cell; Atalla and VanderHart, 1984).…”