Revealing the structures of cellulose nanofiber bundles obtained by mechanical nanofibrillation via TEM observation

Chen, Wenshuai; Li, Qing; Cao, Jun; Liu, Yixing; Li, Jian; Zhang, Jiangshuai; Luo, Shuiyang; Yu, Haipeng

doi:10.1016/j.carbpol.2014.10.024

Cited by 72 publications

(46 citation statements)

References 30 publications

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“…Thus, the disappearance of these peaks with the increasing levels of the NaClO addition in both BHs species indicated that hemicellulose and lignin were removed during oxidation. For BHs, the peak at approximately 1630 cm -1 represented the water absorption of hydrophilic O-H radicals in cellulose (Alemdar and Sain 2008;Yu et al 2012;Hu et al 2014;Chen et al 2015). As the BHs were treated with NaClO in the TEMPO-mediated oxidation system, the peak slightly shifted from approximately 1,630 cm -1 to approximately 1,600 cm -1 , which reconfirmed the observation that the carboxylate groups were introduced to the cellulose structure (Cobut et al 2014).…”

Section: Tempo-mediated Oxidation Of Bamboo Holocellulosesupporting

confidence: 62%

“…For D. membranaceus, the width distribution also ranged widely from 3 nm to 14 nm at a NaClO addition level of 3.0 mmol/g-BHs and became slightly narrower with a range of 3 nm to 10 nm. Both D. asper and D. membranaceus TOBCNs had an average width of 5 nm to 7 nm, which is comparable to bamboo pulp cellulose nanofibrils (2 nm to 6 nm) from the same process (Puangsin et al 2013b) and those from solid bamboo (2 nm to 5 nm) (Chen et al 2015). However, the width of TOBCNs was still smaller than that of bamboo nanocrystalline cellulose (< 20 nm) (Yu et al 2012) and those obtained from a chemiultrasonic process (Chen et al 2011b).…”

Section: Tempo-oxidized Bamboo Cellulose Nanofibrilsmentioning

confidence: 84%

“…The broad peaks at approximately 3,400 cm -1 and approximately 2,800 cm -1 were due to the O-H stretching of the hydroxyl or carboxyl groups and C-H stretching of CH2, respectively (Alemdar and Sain 2008;Yu et al 2012;Hu et al 2014). The peaks at approximately 1,730 cm -1 and 1,240 cm -1 were associated with C=O stretching and vibration, indicating the presence of hemicellulose, phenolic acids, pectin, and xylan (Chen et al 2011(Chen et al , 2015Hu et al 2014) and the C-O stretching of the aryl group in lignin (Jonoobi et al 2009;Kargarzadeh et al 2012;Karimi et al 2014). Thus, the disappearance of these peaks with the increasing levels of the NaClO addition in both BHs species indicated that hemicellulose and lignin were removed during oxidation.…”

Section: Tempo-mediated Oxidation Of Bamboo Holocellulosementioning

confidence: 99%

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Characterization of Bamboo Nanocellulose Prepared by TEMPO-mediated Oxidation

et al. 2018

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The synthesis of TEMPO-oxidized bamboo cellulose nanofibrils (TOBCNs) was attempted using two locally available species in Thailand (Dendrocalamus asper and D. membranaceus). Bamboo powder was first delignified with NaClO2. The obtained bamboo holocelluloses (BHs) were then oxidized via a TEMPO/NaBr/NaClO system in water at pH 10 for 2 h. The effects of NaClO addition level on the weight recovery ratio, carboxylate content, and nanofibrillation yield were studied. At a higher level of NaClO addition, the weight recovery ratio of TEMPO-oxidized bamboo holocelluloses (TOBHs) decreased from 90% to 70%, while the carboxylate content of TOBHs increased up to 0.8 mmol/g to 0.9 mmol/g for both species. Fourier transform infrared spectra indicated that C6-hydroxyl groups of cellulose were converted to negatively-charged carboxylate groups. After a gentle mechanical treatment with water, transparent liquid of TOBCNs were obtained after the removal of unwanted fraction, which gave a nanofibrillation yield of more than 90% at a NaClO addition level of 7.5 mmol/g to 15.0 mmol/g-BHs. Well individualized TOBCNs were successfully prepared and had a length of several microns and an average width of 5 nm to 7 nm under transmission electron microscopy. Thus, ultra-long TOBCNs are applicable for use as nano-reinforced polymer composites in non-food industries.

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Section: Tempo-mediated Oxidation Of Bamboo Holocellulosesupporting

confidence: 62%

Section: Tempo-oxidized Bamboo Cellulose Nanofibrilsmentioning

confidence: 84%

Section: Tempo-mediated Oxidation Of Bamboo Holocellulosementioning

confidence: 99%

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Characterization of Bamboo Nanocellulose Prepared by TEMPO-mediated Oxidation

et al. 2018

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“…In previous studies, there have been many comparisons and exploitations made for cellulose from various types of plants (Das et al 2010;Virtanen et al 2012;Chen et al 2015b). However, there have not been any comparisons of the characteristics of MC obtained from different biomasses, such as EFB and SCB.…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of Microcelluloses Isolated From Two Different Biomasses with Commercial Cellulose

Owi¹,

Ong²,

Sam³

et al. 2016

BioResources

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e Microcelluloses (MCs) were chemically isolated from two different biomass sources, empty fruit bunches (EFB) and sugarcane bagasse (SCB). The resulting MCs were compared to the commercially available cellulose (MCSigma) that was used as a standard. Structural, crystalline, morphological, and thermal properties of all specimens were characterized and compared by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). FTIR analysis verified that the chemical treatments removed non-cellulosic constituents including hemicelluloses and lignin. XRD patterns revealed the crystallinity increment from 43.1% to 52.1% for MC-EFB and 38.9% to 52.4% for MC-SCB. SEM images demonstrated the fibrillar structure of both MC-EFB and MC-SCB, and their surfaces were smoother compared with MC-Sigma. From the TG curves, MC-EFB provided the highest thermal stability, as it had the highest maximum degradation temperature at 345 °C. DSC results showed only one endothermic peak for all specimens. Taken together, these results reasonably confirmed that the MCs from EFB and SCB are comparable to standard MC-Sigma.

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“…The nanocellulose isolation can be traced back to 1950s, Colloidal suspensions of cellulose were first obtained by sulfuric acid (H 2 SO 4 )‐catalyzed degradation of cellulose fibers. Presence of needle‐shaped particles was confirmed by transmission electron microscopy characterization . Electron diffraction revealed that these particles had the same crystalline structure as the original cellulose fibers .…”

Section: Top‐down Isolation Techniquesmentioning

confidence: 82%

Nanobiopolymers Fabrication and Their Life Cycle Assessments

Yang

Zhang

et al. 2018

Biotechnology Journal

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Living organisms produced nanopolymers (nanobiopolymers for short), such as nanocellulose, nanochitin, nanosilk, nanostarch, and microbial nanobiopolymers, having received widely scientific and engineering interests in recent years. Compare with petroleum-based polymers, biopolymers are sustainable and biodegradable. The unique structural features that stem from nanosized effects, such as ultrahigh aspect ratio and length-diameter ratio, further endow nanobiopolymers with high transparence and versatile processability. To fabricate these nanobiopolymers, a variety of mechanical, chemical, and synthetic biology techniques have been developed. The applications of the isolated nanobiopolymers have been extended from polymer fillers into wide emerging high-tech fields, such as biomedical devices, bioplastics, display panels, ultrafiltration membranes, energy storage devices, and catalytic supports. Accordingly, in the review, the authors first introduce isolation techniques to fabricate nanocellulose, nanochitin, nanosilk, and nanostarch. Then, the authors summarized the nanobiopolymers produced from biosynthetic pathway, including microbial polyamides, polysaccharides, and polyesters. On the other hand, most of these techniques require high energy consumption and usage of chemical reagents. In this regard, life cycle assessment offered a quantitative route to precisely evaluate and compare environmental benefits of different artificial isolation approaches, which are also summarized in the second section of the review.

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Revealing the structures of cellulose nanofiber bundles obtained by mechanical nanofibrillation via TEM observation

Cited by 72 publications

References 30 publications

Characterization of Bamboo Nanocellulose Prepared by TEMPO-mediated Oxidation

Characterization of Bamboo Nanocellulose Prepared by TEMPO-mediated Oxidation

Comparative Study of Microcelluloses Isolated From Two Different Biomasses with Commercial Cellulose

Nanobiopolymers Fabrication and Their Life Cycle Assessments

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