Novel insight into cellulose supramolecular structure through 13C CP-MAS NMR spectroscopy and paramagnetic relaxation enhancement

Characterization of cellulose I/II hybrid fibers isolated from energycane bagasse during the delignification process: Morphology, crystallinity and percentage estimation

“…It was reported that a signal at 65 ppm and an upfield shoulder near 63 ppm described the characteristic of cellulose I; whereas cellulose II possessed a broad peak at 63 ppm (Kamide, Kowsaka, & Okajima, 1985;Miura & Nakano, 2015;Zuckerstätter, Terinte, Sixta, & Schuster, 2013). In Fig.…”

13C NMR assignments of regenerated cellulose from solid-state 2D NMR spectroscopy

“…2 wt% of the pulp was dissolved in EMIMAc and coagulated in water, as described above. The regenerated samples were dispersed in Milli-Q water and then dried in oven at 105 • C for 3 h. This was repeated Zuckerstätter et al (2013) is also shown, with fit signals that are attributed to crystalline cellulose II shown in blue, signals from crystalline surfaces in green and signals from disordered material in red. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)…”

“…A narrow signal at 86.2 ppm has been assigned to the crystalline surface species and a broad one at 83.8 ppm to cellulose in disordered regions (Ibbett et al, 2007). The narrow signal at 84.8 ppm has also, tentatively, been assigned to cellulose at crystalline surfaces (Zuckerstätter, Terinte, Sixta, & Schuster, 2013). From the C4 13 C signals, square cross-sectional cellulose models of elementary fibrils and fibril aggregates have been proposed for native (Larsson et al, 1997;Wickholm et al, 1998), and for regenerated cellulose (Zuckerstätter et al, 2013), respectively.…”

“…The narrow signal at 84.8 ppm has also, tentatively, been assigned to cellulose at crystalline surfaces (Zuckerstätter, Terinte, Sixta, & Schuster, 2013). From the C4 13 C signals, square cross-sectional cellulose models of elementary fibrils and fibril aggregates have been proposed for native (Larsson et al, 1997;Wickholm et al, 1998), and for regenerated cellulose (Zuckerstätter et al, 2013), respectively. Using these models, dimensions of elementary fibrils and fibril aggregates (Gårdebjer et al, 2015;Newman, 1999;Wickholm et al, 1998), crystallinity index (CI) (Lee et al, 2016;Park, Johnson, Ishizawa, Parilla, & Davis, 2009) as well as specific surface area (Chunilall, Bush, Larsson, Iversen, & Kindness, 2010) have been estimated and structural changes of the material, for example upon drying and rewetting, have been monitored (Idström, Brelid, Nydén, & Nordstierna, 2013;Östlund, Idström, Olsson, Larsson, & Nordstierna, 2013).…”

Effect of methylimidazole on cellulose/ionic liquid solutions and regenerated material therefrom

“…This can be seen not only at around 107 ppm, where the crystal structure cellulose II has a characteristic peak, but also in the area between 84 and 90 ppm, which originates from C4 in the glucose ring. Peaks at 88.1 and 89.3 ppm are associated with cellulose II crystal interior atoms, while peaks at 86.6 and 85.6 are tentatively assigned to crystal surfaces [39,40]. However, a broad gaussian peak at 84.2 originating from disordered material overlapping the crystalline signals complicates the interpretation of these data [41].…”