Polymorphic transformation of cellulose I to cellulose II by alkali pretreatment and urea as an additive

Gupta, Poonam; Uniyal, Vanshi; Naithani, Sanjay

doi:10.1016/j.carbpol.2013.02.012

Cited by 107 publications

(55 citation statements)

References 39 publications

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“…The second hatched area contains the out-of-plane stretching vibrations of CH bonds in the aromatic rings of crystalline cellulose, as well as the stretching vibrations of CH and COC bonds in the β-(1,4)-glycosidic linkages between the anhydroglucose units. Polymorphism has already been documented for NaOH-treated cellulose [50]. The absorption band at 1160 cm −1 is due to crystalline cellulose (COC asymmetrical stretching).…”

Section: Resultsmentioning

confidence: 94%

Interfacial Characterization by Pull-Out Test of Bamboo Fibers Embedded in Poly(Lactic Acid)

Viel

Esposito

Saiter

et al. 2018

Fibers

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Abstract:In this work, the apparent shear strength at the interface between a bamboo fiber and the surrounding poly(lactic acid) (PLA) matrix is quantified. A method for processing pull-out test samples within a controlled embedded length is proposed and the details of the test procedure are presented, along with a critical discussion of the results. Two series of samples are considered: untreated and mercerized bamboo fibers from the same batch, embedded in the same polyester matrix. Electron and optical microscopy are used to observe the fiber-matrix interface before and after the test, and to identify the failure mode of each sample, especially as regards the occurrence of fibrillation in the fiber bundles. The values of apparent interfacial shear strength are calculated only for regular fibers successfully pulled out from the matrix, and reported with their statistical variations. Mercerization, whose efficiency was proven by Fourier transform infrared (FTIR) spectroscopy, did not appear though to improve the quality of the interface (τ app = 7.0 ± 3.1 MPa for untreated fibers and τ app = 5.3 ± 2.4 MPa for treated fibers).

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Section: Resultsmentioning

confidence: 94%

Interfacial Characterization by Pull-Out Test of Bamboo Fibers Embedded in Poly(Lactic Acid)

Viel

Esposito

Saiter

et al. 2018

Fibers

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“…Thus, the high sensitivity of the activation energy of 240 dissolution value on DP indicates that the cellulose dissolution has been critically controlled by 241 DP value (Qi, Chang & Zhang, 2008). However, the solubility of cellulose samples was not 242 significantly increased with the decreased DP values (Table 1) inter-chain but also inter-plane hydrogen bonds (Gupta, Uniyal & Naithani, 2013). Moreover, 250 upon evaporation of the ammonia, the cellulose I structure reforms its intrasheet hydrogen bonds 251 but settles into the nearest energy minimum forming cellulose III (Sarko, Southwick & Hayashi, 252 1976).…”

Section: Influence Of Crystal Type On Dissolution 236mentioning

confidence: 85%

Effects of polymorphs on dissolution of cellulose in NaOH/urea aqueous solution

Xiong

Chen

You

et al. 2015

Carbohydrate Polymers

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“…Diffractograms displayed three main characteristic peaks assigned to cellulose I in X-ray diffractions, and these are located at approximately 2h = 14°, 16°and 22°Corresponding to 1 1 0 (d 1 spacing), 1 1 0 (d 2 spacing) and 2 0 0 (d 3 spacing) crystallographic planes respectively. The diffractogram peak located at around 2h = 35°, corresponds to 0 4 0 crystallographic plane [37,38]. The X-ray diffractograms, showed no change in peak intensities located at the crystallographic plane reflections, indicating no transformation of cellulose I into cellulose II allomorph due to ultrasonication.…”

Section: X-ray Diffraction Analysis (Xrd)mentioning

confidence: 92%

Fabrication of bacterial cellulose thin films self-assembled from sonochemically prepared nanofibrils and its characterization

Tsalagkas

Lagaňa

Poljanšek

et al. 2016

Ultrasonics Sonochemistry

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Bacterial cellulose (BC) film formation could be a critical issue in nanotechnology applications such as biomedical or smart materials products. In this research, purified pretreated BC was subjected to high intensity ultrasound (HIUS) and was investigated for the development of BC films. The morphological, structural and thermal properties of the obtained films were studied by using FE-SEM, AFM, FT-IR, XRD, TGA and DSC characterizations. Results showed that the most favorable purification treatment was the 0.01 M NaOH at 70°C for 2h under continuous stirring. The most suitable ultrasound operating conditions were found to be, 1cm distance of ultrasonic probe from the bottom of the beaker, submerged in cold water bath cooling around 12 ± 2°C. The power (25 W/cm(2)), time (30 min), BC concentration (0.1%w/w), amplitude (20 μm) and frequency (20 kHz) were maintained constant.

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Polymorphic transformation of cellulose I to cellulose II by alkali pretreatment and urea as an additive

Cited by 107 publications

References 39 publications

Interfacial Characterization by Pull-Out Test of Bamboo Fibers Embedded in Poly(Lactic Acid)

Interfacial Characterization by Pull-Out Test of Bamboo Fibers Embedded in Poly(Lactic Acid)

Effects of polymorphs on dissolution of cellulose in NaOH/urea aqueous solution

Fabrication of bacterial cellulose thin films self-assembled from sonochemically prepared nanofibrils and its characterization

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