The Use of Half Width and Position of the Lines in the X-Ray Diffractograms of Native Cellulose to Characterize the Structural Properties of the Samples.

Gjønnes, J.; Norman, Nicolai; Møller, Jørgen; Detoni, S.

doi:10.3891/acta.chem.scand.12-2028

Cited by 19 publications

(14 citation statements)

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“…In this model the surfaces of the microfibrils form the amorphous region and as a necessary corollary the lateral size of the crystallite is inversely proportional to the crystallinity. While this has not been explicitly stated in the literature, an inverse correlation between X‐ray broadening and the X‐ray fractional crystallinity has been observed by several groups of workers 6–9. In this work we examine a model which can be used to determine the size of the crystallites, and because of the nature of the model adopted can be used to draw certain conclusions about the fractional crystallinity of the sample and its chemical reactivity 9…”

Section: Introductionmentioning

confidence: 88%

On the Interpretation of X‐Ray Diffraction Powder Patterns in Terms of the Nanostructure of Cellulose I Fibres

Garvey

Parker

Simon

2005

Macro Chemistry & Physics

246

154

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Summary: The average lateral dimensions of cellulose microfibrils in paper sheets can be determined from the width of X‐ray Bragg peaks at half the maximum height. The method assumes it is the finite size of the crystallite which is the main contributor to peak broadening in the directions orthogonal to the long axis of the crystallite. This assumption is examined in the context of samples from different botanical sources, of varying crystallinity and cellulose content and the various instrumental sources of broadening X‐ray powder patterns. Excellent fits to the data from paper samples can be obtained by using five Voigt functions to the powder diffraction patterns, for the 101, $10\bar 1$, 021, 002 and 040 reflections. Of these reflections, the 020 is the clearest, and the best able to determine the lateral dimension of the crystallite. Results indicate that the size of microfibrils is dependent on the botanical source of the fibres.

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Section: Introductionmentioning

confidence: 88%

On the Interpretation of X‐Ray Diffraction Powder Patterns in Terms of the Nanostructure of Cellulose I Fibres

Garvey

Parker

Simon

2005

Macro Chemistry & Physics

246

154

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“…2 and 3 showed increasing height at 2h = 188, for increasing degrees of transformation, but the value of CrI never dropped below 39% (Table 1). Gjønnes and Norman (1958) and Ioelovich and Larina (1999) reported lattice expansion in thin crystallites of cellulose I, so that an increase in peak width was associated with a displacement to low values of 2h. A curve published by Gjønnes and Norman (1958) indicated that an increase in peak width to 78 was sufficient to displace the peak to 2h = 218.…”

Section: Waxs Diffractogramsmentioning

confidence: 95%

“…2 and 3. The shoulder was too weak for measurement of the peak width, but the curve published by Gjønnes and Norman (1958) indicated that displacement to 2h = 22.38 corresponded to a peak width of 38, for which Eq. (1) indicated a crystallite thickness of approximately 3 nm.…”

Section: Waxs Diffractogramsmentioning

confidence: 98%

“…Peaks were assigned according to the monoclinic unit cell described by Sugiyama et al (1991). Peak positions and widths were measured from plots by using the method described by Gjønnes and Norman (1958). We did not use curve-fitting software because of the complexity of the diffractograms, with peak positions and widths expected to be related to crystallite dimensions as well as crystalline forms of cellulose, as discussed below.…”

Section: Partial Dissolutionmentioning

confidence: 99%

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Phase transformations in microcrystalline cellulose due to partial dissolution

2007

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All-cellulose composites were prepared by partly dissolving microcrystalline cellulose (MCC) in an 8.0 wt% LiCl/DMAc solution, then regenerating the dissolved portion. Wide-angle X-ray scattering (WAXS) and solid-state 13 C NMR spectra were used to characterize molecular packing. The MCC was transformed to relatively slender crystallites of cellulose I in a matrix of paracrystalline and amorphous cellulose. Paracrystalline cellulose was distinguished from amorphous cellulose by a displaced and relatively narrow WAXS peak, by a 4 ppm displacement of the C-4 13 C NMR peak, and by values of T 2 (H) closer to those for crystalline cellulose than disordered polysaccharides. Cellulose II was not formed in any of the composites studied. The ratio of cellulose to solvent was varied, with greatest consequent transformation observed for c < 15%, where c is the weight of cellulose expressed as % of the total weight of cellulose, LiCl and DMAc. The dissolution time was varied between 1 h and 48 h, with only small additional changes achieved by extension beyond 4 h.

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“…23 The linewidth b of the adjacent BN peak was used to adjust results for instrumental broadening 24…”

Section: Linewidth Measurementsmentioning

confidence: 99%

Variations in the fibre repeat between samples of cellulose I from different sources

Davidson¹,

Newman²,

Ryan³

2004

Carbohydrate Research

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The Use of Half Width and Position of the Lines in the X-Ray Diffractograms of Native Cellulose to Characterize the Structural Properties of the Samples.

Cited by 19 publications

References 0 publications

On the Interpretation of X‐Ray Diffraction Powder Patterns in Terms of the Nanostructure of Cellulose I Fibres

On the Interpretation of X‐Ray Diffraction Powder Patterns in Terms of the Nanostructure of Cellulose I Fibres

Phase transformations in microcrystalline cellulose due to partial dissolution

Variations in the fibre repeat between samples of cellulose I from different sources

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