A Comparative Study on the Characterization of Nanofibers with Cellulose I, I/II, and II Polymorphs from Wood

Wang, Haiying; Li, Suiyi; Wu, Tiantian; Wang, Xiaoxuan; Cheng, Xiaomin; Li, Dagang

doi:10.3390/polym11010153

Cited by 19 publications

(16 citation statements)

References 37 publications

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“…The recovery of the tensile modulus and strength of the CNF/PVDF composites at higher loadings (>2 wt %) could be attributed to increased fiber entanglement and/or increased crystallinity of the composites. The worse bulk performance of the TOCNF/PVDF samples, at higher loadings, is likely due to the loss of fibril crystallinity and transformation to cellulose II following the cellulose oxidation treatment, which reduces the tensile strength of the fibrils [71], as well as the reduced crystallinity of the TOCNF/PVDF films. Interestingly, the surface mechanical properties of the TOCNF/PVDF composites, from 1 to 4 wt %, are better than those of neat PVDF and CNF/PVDF composites of similar loading.…”

Section: Resultsmentioning

confidence: 99%

Effect of Cellulose Nanofibrils and TEMPO-mediated Oxidized Cellulose Nanofibrils on the Physical and Mechanical Properties of Poly(vinylidene fluoride)/Cellulose Nanofibril Composites

Barnes

Jefcoat

Alberts³

et al. 2019

Polymers

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Cellulose nanofibrils (CNFs) are high aspect ratio, natural nanomaterials with high mechanical strength-to-weight ratio and promising reinforcing dopants in polymer nanocomposites. In this study, we used CNFs and oxidized CNFs (TOCNFs), prepared by a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation process, as reinforcing agents in poly(vinylidene fluoride) (PVDF). Using high-shear mixing and doctor blade casting, we prepared free-standing composite films loaded with up to 5 wt % cellulose nanofibrils. For our processing conditions, all CNF/PVDF and TOCNF/PVDF films remain in the same crystalline phase as neat PVDF. In the as-prepared composites, the addition of CNFs on average increases crystallinity, whereas TOCNFs reduces it. Further, addition of CNFs and TOCNFs influences properties such as surface wettability, as well as thermal and mechanical behaviors of the composites. When compared to neat PVDF, the thermal stability of the composites is reduced. With regards to bulk mechanical properties, addition of CNFs or TOCNFs, generally reduces the tensile properties of the composites. However, a small increase (~18%) in the tensile modulus was observed for the 1 wt % TOCNF/PVDF composite. Surface mechanical properties, obtained from nanoindentation, show that the composites have enhanced performance. For the 5 wt % CNF/PVDF composite, the reduced modulus and hardness increased by ~52% and ~22%, whereas for the 3 wt % TOCNF/PVDF sample, the increase was ~23% and ~25% respectively.

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Section: Resultsmentioning

confidence: 99%

Effect of Cellulose Nanofibrils and TEMPO-mediated Oxidized Cellulose Nanofibrils on the Physical and Mechanical Properties of Poly(vinylidene fluoride)/Cellulose Nanofibril Composites

Barnes

Jefcoat

Alberts³

et al. 2019

Polymers

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“…mongolica after alkali treatment displayed changes in crystalline structure marked by spectral changes including a decrease in intensity of the band from 1428 cm −1 and a shift at 1418 cm −1 . Additionally, the disappearance of the peak at 1507 cm −1 from purified wood pulp was attributed to the removal of lignin, while the peak at 1737 cm −1 was attributed to the leaching of hemicellulose after treatments with alkali [63].…”

Section: Quality Marker Regions and Their Significancementioning

confidence: 99%

Comparative FT-IR Prospecting for Cellulose in Stems of Some Fiber Plants: Flax, Velvet Leaf, Hemp and Jute

et al. 2021

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Plant fibers are sustainable sources of materials for many industries, and can be obtained from a variety of plants. Cellulose is the main constituent of plant-based fibers, and its properties give the characteristics of the fibers obtained. Detailed characterization of cellulosic fibers is often performed after lengthy extraction procedures, while fast screening might bring the benefit of quick qualitative assessment of unprocessed stems. The aim of this research was to define some marker spectral regions that could serve for fast, preliminary qualitative characterization of unprocessed stems from some textile plants through a practical and minimally invasive method without lengthy extraction procedures. This could serve as a screening method for sorting raw materials by providing an accurate overall fingerprint of chemical composition. For this purpose, we conducted comparative Fourier Transform Infrared Spectroscopy (FT-IR) prospecting for quality markers in stems of flax (Linum usitatissimum L.), velvet leaf (Abutilon theophrasti Medik.), hemp (Cannabis sativa L.) and jute (Corchorus olitorius L.). Analysis confirmed the presence of major components in the stems of the studied plants. Fingerprint regions for cellulose signals were attributed to bands at 1420–1428 cm−1 assigned to the crystalline region and 896–898 cm−1 assigned to the amorphous region of cellulose. The optimization of characterization methods for raw materials is important and can find immediate practical applications.

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“…Compared with the primary and secondary diffraction peaks at 2θ = 21.0° and 16.5° of RCF, the primary and secondary diffraction peaks of 2θ = 21.9° and 17.5° shift toward right when the concentration of nanocellulose is 0.1% in the ANF. The phenomenon indicates that the content of cellulose-I was signi cantly reduced and cellulose-II was increased gradually when the concentration of added nanocellulose is 0.1% and further indicates the transformation of cellulose-I to cellulose-II in the ANF [15] . This may be caused by the formation of holes in the sample after ultrasonic treatment during the preparation of cellulose, and the formation of a certain molecular orientation due to a small amount of nanocellulose, which further deepened the trend of conversion to cellulose-II [11] .…”

Section: Xrd Analysismentioning

confidence: 94%

Crystalline Structure Analysis of All-cellulose Nanocomposites Films Based on Corn and Wheat Straw

Bian

Yang

2021

Preprint

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The cellulose and nanocellulose which was extracted from corn straw and wheat straw was used to fabricate all-cellulose nanocomposites film (ANF). The crystal structure (CS) of ANFs was analyzed by X-ray diffraction (XRD) and Fourier transform infrared spectrometry (FTIR). The result shows that cellulose-I and cellulose-II are coexisting within regenerated cellulose films (RCF) and ANFs and can transfer each other with the change of nanocellulose content. The characteristics of cellulose transformation depend on the raw material and preparing method of cellulose. When cellulose is prepared from corn straw, under two preparing methods, the cellulose type tends to transform from cellulose-I to cellulose-II with low nanocellulose content and transform from cellulose-II to cellulose-I with high nanocellulose content. However, when cellulose is prepared from wheat straw, under extracting methods, the cellulose type tends to transform from cellulose-I to cellulose-II with nanocellulose content increase; under acid-alkali methods, the transformation is from cellulose-II to cellulose-I. The crystalline index (CI) of RCFs and ANFs is no obvious regularity, and the either content of cellulose-I or cellulose-II alone cannot determine the CI. Based on above result, the transformation characteristics of cellulose type should affect the property of ANFs, but further research methods and strategies are needed on what the effects are.

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A Comparative Study on the Characterization of Nanofibers with Cellulose I, I/II, and II Polymorphs from Wood

Cited by 19 publications

References 37 publications

Effect of Cellulose Nanofibrils and TEMPO-mediated Oxidized Cellulose Nanofibrils on the Physical and Mechanical Properties of Poly(vinylidene fluoride)/Cellulose Nanofibril Composites

Effect of Cellulose Nanofibrils and TEMPO-mediated Oxidized Cellulose Nanofibrils on the Physical and Mechanical Properties of Poly(vinylidene fluoride)/Cellulose Nanofibril Composites

Comparative FT-IR Prospecting for Cellulose in Stems of Some Fiber Plants: Flax, Velvet Leaf, Hemp and Jute

Crystalline Structure Analysis of All-cellulose Nanocomposites Films Based on Corn and Wheat Straw

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