Acylation of cellulose nanocrystals with acids/trifluoroacetic anhydride and properties of films from esters of CNCs

Huang, Feng Yuan; Wu, Xiang-Feng; Yu, Yan; Lü, Yanhua; Chen, Qifan

doi:10.1016/j.carbpol.2016.09.010

Cited by 43 publications

(11 citation statements)

References 58 publications

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“…Therefore, it is important that the crystallinity of jute fibers and JSE be precisely determined. The crystal structure of natural cellulose is mainly cellulose I, and its peak position is about at 2θ = 16.6, 22.6 and 34.6 ° [39]. The XRD curves of jute fibers and JSE are shown in Fig.…”

Section: The Crystallinity Of Jute Fibers and Jsementioning

confidence: 99%

“…In addition, it can be seen from the figure that there was no new peaks appeared and old peaks disappeared of JSE, but the peak area and intensity changed slightly, the type of crystallization did not change. The crystallinity was calculated according to formula 1 [38][39][40][41]. Where I 200 and I am were the intensity of the peak at 2θ about 22.5 and 18.0 °, respectively.…”

Section: The Crystallinity Of Jute Fibers and Jsementioning

confidence: 99%

“…Crystallinity increased may be caused by two reasons, on the one hand, part of crystalline and amorphous cellulose molecular rearrangement in the chain, forming a new crystalline structure, so the crystallinity increased. on the other hand, the crystalline structure of cellulose was destroyed by acidic substance produced from the degradation of lignin, hemicellulose and mechanical destruction, therefore the crystallinity decreased [39]. While the former plays an important role, therefore, the overall result was crystallinity increased.…”

Section: The Crystallinity Of Jute Fibers and Jsementioning

confidence: 99%

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Effect of a promising CSESE pretreatment on the morphological structure and properties of jute fibers

Sun

Hong-zhen

et al. 2021

E3S Web Conf.

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Plant fiber has a complex aggregated structure, high crystallinity and a large number of hydrogen bonds, and has low chemical reaction activity. Therefore, in order to improve the reactivity, the plant fiber needs to be pretreated before chemical modification. Therefore, the pretreatment method has an important influence on the chemical modification of plant fibers. In this paper, Jute fibers were successively treated by particular continuous screw-extrusion steam explosion (CSESE). The effects on the morphological ructure, composition, thermal and crystalline properties of jute fibers before and after treated were investigated. Scanning electron microscopy (SEM) showed that the morphological structure changed significantly after CSESE pretreatment, the diameter was smaller, the surface cracks and the specific surface area increased. There was no new functional groups appeared in fourier transform infrared spectroscopy (FTIR). Composition analysis demonstrated that the content of hemicellulose and extractive decreased, but cellulose and lignin increased. The crystallinity of JSE increased from 66.31 % to 70.19 %. X-ray photoelectron spectroscopy (XPS) suggested that the cellulose and lignin content increased. Thermogravimetric analysis (TGA) demonstrated that the initial decomposition temperature of JSE increased from 334.4 to 355.2°C. DMA indicated that the Tg of JSE reduced from 92.6 to 90.0°C. Therefore, for jute fiber, the CSESE pretreatment is an effective and promising pretreatment method for further chemical modification, biofuels and chemical products.

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Section: The Crystallinity Of Jute Fibers and Jsementioning

confidence: 99%

Section: The Crystallinity Of Jute Fibers and Jsementioning

confidence: 99%

Section: The Crystallinity Of Jute Fibers and Jsementioning

confidence: 99%

See 1 more Smart Citation

Effect of a promising CSESE pretreatment on the morphological structure and properties of jute fibers

Sun

Hong-zhen

et al. 2021

E3S Web Conf.

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“…However, their application is limited by poor compatibility between NCC and nonpolar polymer media or matrices due to polar properties of NCC [5]. Chemical modification of NCC was proposed to address this issue [6,7,8,9,10,11,12,13,14,15,16]. The methods for chemical modification of NCC include isocyanation [6], esterification [6], silanation [7,8,9,10], oxidation [11,12], and acylation [13,14,15].…”

Section: Introductionmentioning

confidence: 99%

An Effective, Economical and Ultra-Fast Method for Hydrophobic Modification of NCC Using Poly(Methylhydrogen)Siloxane

You

et al. 2019

Polymers

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Poor compatibility between nanocellulose crystals (NCCs) and major polymers has limited the application of NCC as bio-reinforcements. In this work, an effective and ultra-fast method was investigated to significantly improve the hydrophobicity of NCC by using poly(methylhydrogen)siloxane (PMHS) as modifier. PMHS possessed amounts of reactive –Si–H groups and hydrophobic –CH3 groups. The former groups were reactive with the hydroxyl groups of NCC, while the latter groups afforded NCC very low surface energy. As the weight ratio of PMHS to NCC was only 0.0005%, the hydrophobicity of NCC was significantly improved by increasing the water contact angle of NCC from 0° to 134°. The effect of weight ratio of PMHS to NCC and the hydrogen content of –Si–H in PMHS on the hydrophobicity and thermal stability was investigated in detail by Fourier transform infrared spectroscopy (FTIR), (X-ray Diffraction) XRD and (thermogravimetric analysis) TGA. The results indicated that PMHS chains were covalently grafted onto NCC and PMHS modification improved the thermal stability of NCC.

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“…The chemical modification of NCC is an effective method for improving the interface compatibility of the subsequent bionanocomposites. The modification method could be classified into the following types: isocyanation [7], esterification [8], silanation [9,10,11], oxidation [12,13], acylation and so on [14]. For example, Siqueira et al [7] prepared hydrophobic NCCs by n-octadel isocyanate (C 18 H 37 NCO) modification.…”

Section: Introductionmentioning

confidence: 99%

Hydrophobic Modification of Nanocellulose via a Two-Step Silanation Method

Lin

You

et al. 2018

Polymers

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Dodecyltrimethoxysilane (DTMOS), which is a silanation modifier, was grafted onto nanocellulose crystals (NCC) through a two-step method using KH560 (ɤ-(2,3-epoxyproxy)propytrimethoxysilane) as a linker to improve the hydrophobicity of NCC. The reaction mechanism of NCC with KH560 and DTMOS and its surface chemical characteristics were investigated using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and HCl–acetone titration. These analyses confirmed that KH560 was grafted onto the surface of NCC through the ring-opening reaction, before DTMOS was covalently grafted onto the surface of NCC using KH560 as a linker. The grafting of NCC with DTMOS resulted in an improvement in its hydrophobicity due to an increase in its water contact angle from 0° to about 140°. In addition, the modified NCC also possessed enhanced thermal stability.

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Acylation of cellulose nanocrystals with acids/trifluoroacetic anhydride and properties of films from esters of CNCs

Cited by 43 publications

References 58 publications

Effect of a promising CSESE pretreatment on the morphological structure and properties of jute fibers

Effect of a promising CSESE pretreatment on the morphological structure and properties of jute fibers

An Effective, Economical and Ultra-Fast Method for Hydrophobic Modification of NCC Using Poly(Methylhydrogen)Siloxane

Hydrophobic Modification of Nanocellulose via a Two-Step Silanation Method

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