Theoretical and experimental developments for accurate determination of crystallinity of cellulose I materials

Driemeier, Carlos; Calligaris, Guilherme A.

doi:10.1107/s0021889810043955

Cited by 107 publications

(95 citation statements)

References 24 publications

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“…Note that most of the methods incorrectly assume that X-ray sensitivity to crystalline and amorphous phases is the same. The Rietveld fitting of XRD data can resolve these uncertainties in the CI calculation [45]. Because these advanced methods are not easily amenable to non-XRD experts, a more user-friendly method has been developed [46].…”

Section: Correlation Of "Apparent" Crystallinity Estimated From Xrd mentioning

confidence: 99%

Correlations of Apparent Cellulose Crystallinity Determined by XRD, NMR, IR, Raman, and SFG Methods

Lee

Dazen

Kafle

et al. 2015

Advances in Polymer Science

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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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Section: Correlation Of "Apparent" Crystallinity Estimated From Xrd mentioning

confidence: 99%

Correlations of Apparent Cellulose Crystallinity Determined by XRD, NMR, IR, Raman, and SFG Methods

Lee

Dazen

Kafle

et al. 2015

Advances in Polymer Science

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“…The traditional cellulose model describes cellulose chains as containing ordered, crystalline and amorphous (less ordered) regions. The X-ray diffraction method considers the contributions from crystalline and amorphous cellulose to the entire XRD spectra and is generally regarded an accurate technique of the crystallinity index measurement, although the crystallinity values obtained by this method may be higher than those obtained by the other methods (Park et al 2010;Cao and Tan 2005;Driemeier and Calligaris 2011). The X-ray diffractograms of the seven kraft pulps, which were produced as described above, suggested the presence of amorphous and crystalline regions.…”

Section: Characterization Of Cellulosic Pulpsmentioning

confidence: 99%

Conversion of various types of lignocellulosic biomass to fermentable sugars using kraft pulping and enzymatic hydrolysis

et al. 2017

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The aim of this work was to assess the utility of seven different kraft pulps produced from softwood (pine), hardwood (poplar, birch and beech), wheat straw and hemp (bast and harl) as potential sources of sugar feedstocks for fermentation processes. The pulps contained low amounts of hemicelluloses (1.9-8.2% d.w.) and lignin (1.7-15% d.w.). The crystallinity index values ranged from 55% (wheat straw pulp) to 79% (hemp bast pulp), while the average DP varied from around 230 (hemp bast pulp) to 1482 (poplar and birch pulps). The results of enzymatic hydrolysis showed that not only the residual lignin content but also the cellulose crystallinity index decided on the sugar yields while the average polymerization degree had a weak impact. More reducing sugars were obtained from the hardwood pulps and wheat straw pulp (100% d.w.) than from the pine pulp (around 89% d.w.) and two hemp pulps (40.5% d.w. and 44.7% d.w. from the bast and harl pulps, respectively). Glucose was the dominating (69-79% w/w) soluble sugar in enzymatic hydrolysates of the pulps. The sugar profiles of these hydrolysates make them suitable sugar feedstocks for fermentation processes.

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“…Largely XRD is reported and the Rietveld refinement is commonly considered to be the most accurate method. 97 In a recent publication however, Ahvenainen et al found good correlation with the five most common XRD fitting methods and the two dimensional Rietveld method. 98 Moreover, within their work it is emphasized that comparison between samples and laboratories is extremely challenging.…”

Section: Blue Goose Biorefineriesmentioning

confidence: 99%

Benchmarking Cellulose Nanocrystals: From the Laboratory to Industrial Production

2016

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Abstract:The renewability, biocompatibility and mechanical properties of cellulose nanocrystals (CNCs) have made them an attractive material for numerous composite, biomedical and rheological applications. However, for CNCs to shift from laboratory curiosity to commercial applications, researchers must transition from CNCs extracted at the bench scale to material produced at an industrial scale. There are a number of companies currently producing kilogram to ton per day quantities of sulfuric acid-hydrolyzed CNCs, as well as other nanocelluloses, as described herein.With the recent intensification of industrially produced CNCs, the variety of cellulose sources, hydrolysis methods and purification procedures, characterization of these materials becomes critical. This has further been justified by the past two decades of research which demonstrate that CNC stability and behaviour is highly dependent on surface chemistry, surface charge density and particle size. This work outlines key test methods that should be employed to characterize these properties to ensure a "known" starting material and consistent performance.Of the sulfuric acid-extracted CNCs examined, industrially produced material compared well with laboratory-made CNCs, exhibiting similar charge density, colloidal and thermal stability, crystallinity, morphology and self-assembly behaviour. In addition, it was observed that further purification of CNCs, using Soxhlet extraction in ethanol, had minimal impact on nanoparticle properties and is unlikely to be necessary for many applications. Overall the current standing of industrially produced CNCs is positive suggesting that the evolution to commercial scale applications will not be hindered by CNC production.

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Theoretical and experimental developments for accurate determination of crystallinity of cellulose I materials

Cited by 107 publications

References 24 publications

Correlations of Apparent Cellulose Crystallinity Determined by XRD, NMR, IR, Raman, and SFG Methods

Correlations of Apparent Cellulose Crystallinity Determined by XRD, NMR, IR, Raman, and SFG Methods

Conversion of various types of lignocellulosic biomass to fermentable sugars using kraft pulping and enzymatic hydrolysis

Benchmarking Cellulose Nanocrystals: From the Laboratory to Industrial Production

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