TEMPO-oxidized cellulose nanofibrils prepared from various plant holocelluloses

Kuramae, Ryota; Saito, Tsuguyuki; Isogai, Akira

doi:10.1016/j.reactfunctpolym.2014.06.011

Cited by 105 publications

(79 citation statements)

References 30 publications

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“…3,7 Most recently, TEMPO-oxidized cellulose nanofibrils have been prepared from several plant holocelluloses 19,20 to show dissolution of most of hemicelluloses under the basic condition (pH 10), leaving ∼1−5% hemicellulose in the resulting nanofibrils, depending on the plant sources. 20 However, how hemicelluloses affect the defibrillation of holocellulose or the behaviors of the resulting nanocellulose has not been clearly delineated.…”

Section: Introductionmentioning

confidence: 99%

Surface and Structure Characteristics, Self-Assembling, and Solvent Compatibility of Holocellulose Nanofibrils

Hsieh

2015

ACS Appl. Mater. Interfaces

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Rice straw holocellulose was TEMPO-oxidized and mechanically defibrillated to produce holocellulose nanofibrils (HCNFs) at 33.7% yield (based on original rice straw mass), 4.6% higher yield than cellulose nanofibril (CNF) generated by the same process from pure rice straw cellulose. HCNFs were similar in lateral dimensions (2.92 nm wide, 1.36 nm thick) as CNF, but longer, less surface oxidized (69 vs 85%), and negatively charged (0.80 vs 1.23 mmol/g). HCNFs also showed higher affinity to hydrophobic surfaces than CNFs while still attracted to hydrophilic surfaces. By omitting hemicellulose/silica dissolution step, the two-step 2:1 toluene/ethanol extraction and acidified NaClO 2 (1.4%, pH 3−4, 70°C, 6 h) delignification process for holocellulose was more streamlined than that of pure cellulose, while the resulting amphiphilic HCNFs were more hydrophobic and self-assembled into much finer nanofibers, presenting unique characteristics for new potential applications.

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Section: Introductionmentioning

confidence: 99%

Surface and Structure Characteristics, Self-Assembling, and Solvent Compatibility of Holocellulose Nanofibrils

Hsieh

2015

ACS Appl. Mater. Interfaces

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“…As the alpha-cellulose content of D. asper was 68.5% and that for D. membranaceus was 67.9%, the BHs contained rather high amounts of hemicellulose and lignin. At the maximum NaClO addition level, the carboxylate content of BHs still remained less than 1.0 mmol/g, as the high level of residual lignin and hemicellulose present in the BHs caused a lower efficiency in the formation of carboxylate groups after oxidation, because it consumed chemicals during TEMPO-mediated oxidation (Okita et al 2009;Kuramae et al 2014).…”

Section: Tempo-mediated Oxidation Of Bamboo Holocellulosementioning

confidence: 99%

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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“…However, for environmental reasons, sulfur-free pulping of, and cellulose-isolation from Japanese cedar wood is necessary, because the odor of methyl mercaptan is a serious problem [17][18][19]. Puangsin et al [20] and Kuramae et al [21] used various wood and non-wood holocelluloses containing significant amounts of hemicelluloses for the preparation of TOCNs.…”

Section: Introductionmentioning

confidence: 99%

Creation of a new material stream from Japanese cedar resources to cellulose nanofibrils

Shi

Yang

Ono

et al. 2015

Reactive and Functional Polymers

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a b s t r a c tJapanese cedar is one of the most abundant plantation softwoods in Japan, although it is not effectively utilized as a wood resource. Japanese cedar cellulose was isolated and subjected to one-pot catalytic oxidation and reduction with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and NaBH 4 , respectively. The TEMPO-oxidized and NaBH 4 -reduced Japanese cedar celluloses (TOCs-NaBH 4 ) had carboxylate content of up to 1.4 mmol/g and viscosity-average degrees of polymerization from 2000 to 3000. The X-ray diffraction patterns of the TOCsNaBH 4 showed that the crystal widths were~3 nm, indicating that the C6-OH groups present on the crystalline cellulose microfibril surfaces were selectively oxidized to C6-carboxylate groups. When the TOCs-NaBH 4 with carboxylate content of 0.9-1.4 mmol/g were mechanically disintegrated in water, transparent TEMPO-oxidized cellulose nanofibril (TOCN) dispersions were obtained. The lengths of the TOCNs, determined from their atomic force microscopy images, varied from 800 to 1500 nm, depending on the oxidation conditions. The TOCNs prepared from Japanese cedar cellulose have an average of high aspect ratios (N300), which is greater than that (~150) prepared from wood pulp and thus advantageous.

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TEMPO-oxidized cellulose nanofibrils prepared from various plant holocelluloses

Cited by 105 publications

References 30 publications

Surface and Structure Characteristics, Self-Assembling, and Solvent Compatibility of Holocellulose Nanofibrils

Surface and Structure Characteristics, Self-Assembling, and Solvent Compatibility of Holocellulose Nanofibrils

Characterization of Bamboo Nanocellulose Prepared by TEMPO-mediated Oxidation

Creation of a new material stream from Japanese cedar resources to cellulose nanofibrils

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