Preparation and Properties of Regenerated Sisal Cellulose from a Homogeneous Solution

2014 ◽  
Vol 700 ◽  
pp. 265-269
Author(s):  
Fei Wang ◽  
Huan Liu ◽  
Ji Hua Li ◽  
Xiao Yi Wei ◽  
Yi Hong Wang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Homogeneous Solution ◽  
Regenerated Cellulose ◽  
Cellulose Ii ◽  
Optimal Conditions ◽  
Cellulose I ◽  
Natural Cellulose ◽  
Ft Ir ◽  
Ir Analysis ◽  
Application Fields

The sisal cellulose was dissolved in ILs under optimal conditions of 150°C and 400W. The structure of sisal cellulose was changed from cellulose I to cellulose II, accompanied with the decrease of crystallinity through XRD, FT-IR analysis. According to the result of GPC, molecular weight distribution became more uniformly and narrow. This is because intra-and inter-hydrogen bond existed in cellulose were destroyed during the dissolution process in ILs. And the regenerated cellulose possessed better properties than the former, which could broaden the application fields of natural cellulose.

scholarly journals Fucoidan Extracted From Sporophyll of Undaria pinnatifida Grown in Weihai, China – Chemical Composition and Comparison of Antioxidant Activity of Different Molecular Weight Fractions

2021 ◽  
Vol 8 ◽  
Author(s):  
Jing Yu ◽  
Qianqian Li ◽  
Jun Wu ◽  
Xiaotong Yang ◽  
Shiping Yang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Chemical Composition ◽  
Undaria Pinnatifida ◽  
Resonance Spectroscopy ◽  
Antioxidant Ability ◽  
Carbohydrate Polymer ◽  
Ft Ir ◽  
Primary Antioxidant ◽  
Ir Analysis ◽  
Molecular Weight Fractions

Fucoidan is a multifunctional marine carbohydrate polymer that differs in its chemical composition and bioactivity both between seaweed species and within species from different locations across the globe. In this study, fucoidan was extracted from the sporophyll of Undaria pinnatifida grown in Weihai, Shandong Province, China. Fucoidan fractions with molecular weight cutoffs (MWCO) of >300 kDa and <10 kDa were obtained via dialysis. The fucoidan standard from Sigma (Fstd, ≥95, CAS: 9072-19-9), fucoidan crude extract (WH), >300 kDa fraction (300k) and <10 kDa fraction (10k) were compared in terms of chemical composition and antioxidant capacity. Based on Fourier transform infrared spectroscopy (FT-IR) analysis, Fstd, WH, and 300k all showed strong bands around 830 cm−1, corresponding to the sulfate substituent in the molecule. The results showed that compared with WH and 300 k, the degree of sulfation at 10k was the lowest. From Nuclear magnetic resonance spectroscopy (NMR) result, the four fucoidan samples all contain α-L-fucose. The primary antioxidant ability of the 10k is significantly higher than that of the 300k, WH, and Fstd, but the secondary antioxidant capabilities of the 10k and 300k were similar, and both were higher than that of the butylated hydroxyanisole (BHA). The ferric reducing antioxidant ability was higher in the 300k and WH fractions. This demonstrates that fucoidan extracted from U. pinnatifida grown in Weihai, China should be a useful nutraceutical resource.

scholarly journals On the orientation of the chains in the mercerized cellulose

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dmitry V. Zlenko ◽  
Daria N. Vtyurina ◽  
Sergey V. Usachev ◽  
Aleksey A. Skoblin ◽  
Mariya G. Mikhaleva ◽  
...  
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Alkaline Treatment ◽  
Point Of View ◽  
Regeneration Process ◽  
Cellulose Ii ◽  
Theoretical Point ◽  
Cellulose I

AbstractThe cold alkaline treatment or mercerization of cellulose is widely used in industry to enrich the cellulose raw with high-molecular-weight $$\alpha$$ α -cellulose. Washing out of hemicelluloses by alkalies is accompanied by the rearrangement of the cellulose chains’ packing, well known as a transition between cellulose I and cellulose II. Cellulose II can also be produced by the precipitation of the cellulose solutions (regeneration). The currently accepted theory implies that in cellulose II, both mercerized and regenerated, the macromolecules are arranged antiparallelly. However, forming such a structure in the course of the mercerization seems to be significantly hindered, while it seems to be quite possible in the regeneration process. In this work, we discuss the sticking points in the theory on the antiparallel structure of mercerized cellulose from a theoretical point of view summarizing all of the available experimental data in the field.

Structure and Properties of Natural Cellulose Extracted from Pineapple Leaf

2013 ◽  
Vol 815 ◽  
pp. 379-385 ◽  
Author(s):  
Tiao Kun Fu ◽  
Ji Hua Li ◽  
Qing Huang Wang ◽  
He Huang ◽  
Xiao Yi Wei ◽  
...  
Keyword(s):  
Amorphous Region ◽  
Regenerated Cellulose ◽  
Crystalline Region ◽  
Ftir Analysis ◽  
Structure And Properties ◽  
Cellulose I ◽  
Porous Network ◽  
Agriculture Waste ◽  
Natural Cellulose ◽  
Pretreatment Conditions

Utilization of agriculture waste has been an issue around the world. In this study, the natural cellulose was extracted from pineapple leaf. Under the optimal pretreatment conditions of 25 g/L, 368 K and 6 h, the ratio of obtained cellulose was above 85 wt%. The structure of obtained cellulose at different stage was confirmed by XRD results. Origin cellulose (OC) and pretreated cellulose (PC) belong to be cellulose I, while regenerated cellulose possessed cellulose II structure, attributed to the dissolution of ionic liquid which destroyed the hydrogen bonds between the cellulose molecules. On the other hand, the structure could be explained by the morphology analysis of OC, PC and RC. The porous network structure of RC led to the reduction of ordered crystalline region and the decrease of crystallinity (CrI), which was proved by BET results. However, the dissolution was testified to be a physical process through FTIR analysis, the existence of characteristic absorption peaks of cellulose. The thermal stability was decreased through pretreatment, dissolution processes, corresponding to the decrease of CrI. The disordered amorphous region of RC decides convenient for production and broad applications.

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

2021 ◽  
Author(s):  
Hongxia BIAN ◽  
Yanyan Yang ◽  
Peng Tu
Keyword(s):  
Wheat Straw ◽  
Raw Material ◽  
Infrared Spectrometry ◽  
Regenerated Cellulose ◽  
Cellulose Ii ◽  
Content Increase ◽  
Cellulose I ◽  
Corn Straw ◽  
Regenerated Cellulose Films ◽  
Cellulose Nanocomposites

Abstract 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.

scholarly journals Elucidation of the Relationship between Intrinsic Viscosity and Molecular Weight of Cellulose Dissolved in Tetra-N-Butyl Ammonium Hydroxide/Dimethyl Sulfoxide

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1605 ◽  
Author(s):  
Bu ◽  
Hu ◽  
Yang ◽  
Yang ◽  
Wei ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Dimethyl Sulfoxide ◽  
Intrinsic Viscosity ◽  
Molecular Level ◽  
Ammonium Hydroxide ◽  
Degree Of Polymerization ◽  
Regenerated Cellulose ◽  
Natural Cellulose ◽  
The Relationship

The determination of molecular weight of natural cellulose remains a challenge nowadays, due to the difficulty in dissolving cellulose. In this work, tetra-n-butylammonium hydroxide (TBAH) and dimethyl sulfoxide (DMSO) aqueous solution (THDS) were used to dissolve cellulose in a few minutes under room temperature into true molecular solutions. That is to say, the cellulose was dissolved in the solution in molecular level, and the viscosity of the solution is linearly dependent on the concentration of cellulose. The relationship between the molecular weight of cellulose and the intrinsic viscosity tested in such dilute solutions has been established in the form of the Mark–Houwink equation, η=0.24×DP1.21. The value of 1.21 indicates that the cellulose molecules dissolve in THDS quite well. The cellulose dispersion in the THDS was proved to be in molecular level by atomic force microscope (AFM) and dynamic light scattering (DLS). The reliability of the established Mark–Houwink equation was cross-checked by the gel permeation chromatography (GPC) and traditional copper (II) ethylenediamine (CED) method. No considerate degradation was observed by comparing the intrinsic viscosity and the degree of polymerization (DP) values of the original with and the regenerated cellulose samples. The natural cellulose can be molecularly dispersed in the multiple-component solvent (THDS), and kept stable for a certain period. A time efficient and reliable method has been supplied for determination of the degree of polymerization and the molecular weight of cellulose.

scholarly journals Detection and quantitation of cellulose II by Raman spectroscopy

2021 ◽  
Author(s):  
Umesh P. Agarwal ◽  
Sally A. Ralph ◽  
Carlos Baez ◽  
Richard S. Reiner
Keyword(s):  
Raman Spectroscopy ◽  
Crystalline Cellulose ◽  
Cellulose Ii ◽  
Raman Intensity ◽  
Cellulose I ◽  
X Ray ◽  
Pure Cellulose ◽  
Natural Cellulose ◽  
Intensity Ratios ◽  
Cellulose Materials

Abstract In cellulose materials, the cellulose II polymorph is often present either exclusively or inconjunction with cellulose I, the natural cellulose. Moreover, in regenerated andmercerized fibers (e,g., viscose and lyocell), natural cellulose adopts to the crystalstructure cellulose II Therefore, its detection and quantitation are important for acomplete assessment of such materials investigations. In the Raman spectra of suchmaterials, a band at 577 cm -1 is typically observed indicating the presence of thispolymorph. In the present study, to quantify the content of cellulose II, a calibrationmethod was developed based on the intensity of the 577 cm -1 peak relative to the1096 cm -1 band of cellulose. For this purpose, in addition to pure cellulose I andcellulose II samples (respectively, Avicel PH-101 and mercerized Avicel PH-101; hencereferred to as Avicel I and Avicel II), a set of five samples were produced by mixingthem in known quantities of Avicel I and Avicel II. The crystalline cellulose II contents ofthe samples were calculated based on the X-ray crystallinity of mercerized Avicel I.These seven samples were included in the calibration set and their Raman spectrawere obtained. Subsequently, Raman intensity ratios I 577 /I 1096 were calculatedby taking ratios of peak intensities at 577 and 1096 cm -1 . These ratios were plottedagainst the % of crystalline cellulose II present in the calibration set samples and thetwo were found to be linearly correlated (R 2 = 0.9944). The set-samples were alsoanalyzed using XRD which were then compared with the Raman method developedhere. Compared to XRD, the Raman method was found to be more sensitive atdetecting and quantifying cellulose II. Additionally, several cellulose II containingmaterials were analyzed by the new Raman method.

Structure of Regenerated Celluloses Treated with Ionic Liquids and Comparison of their Enzymatic Digestibility by Purified Cellulase Components

2012 ◽  
Vol 65 (11) ◽  
pp. 1491 ◽  
Author(s):  
Masahiro Mizuno ◽  
Shuji Kachi ◽  
Eiji Togawa ◽  
Noriko Hayashi ◽  
Kouichi Nozaki ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Crystal Form ◽  
Regenerated Cellulose ◽  
Cellulose Ii ◽  
Cellulose I ◽  
Acid Moiety ◽  
Amino Acid Moiety ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of ◽  
Disordered Chain

In this study, regenerated celluloses were prepared from microcrystalline cellulose (MCC) by treatment with three ionic liquids (ILs) having 1-ethyl-3-methylimidazolium (Emim) as the cation, and the IL N-(2-methoxyethyl)-N,N-diethyl-N-methylammonium alanine ([N221ME][Ala]), where the amino acid moiety is the anion. The crystal form of cellulose was transformed from cellulose I to cellulose II by dissolution with an IL and regeneration with anti-solvent. However, the crystallinity of the regenerated cellulose was different; the disordered chain region was increased in the order of [N221ME][Ala] < [Emim][OAc] < [Emim][DEP] < [Emim][Cl]. The monocomponent cellulase, especially endoglucanase, showed high hydrolyzing activity for regenerated cellulose compared with untreated cellulose. Furthermore, the degree of increase of hydrolyzing activity was almost coincident with the order of crystallinity. For the effective hydrolysis of cellulose treated with an IL, it is necessary to prepare the cellulase mixture containing an adequate ratio of each cellulase component according to crystal allomorph and the crystallinity of regenerated cellulose.

scholarly journals Crystalline structure analysis of all-cellulose nanocomposite films based on corn and wheat straws

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 8353-8365
Author(s):  
Hongxia Bian ◽  
Yanyan Yang ◽  
Peng Tu
Keyword(s):  
Wheat Straw ◽  
Raw Material ◽  
Nanocomposite Films ◽  
Infrared Spectrometry ◽  
Regenerated Cellulose ◽  
Cellulose Ii ◽  
Cellulose Solution ◽  
Clear Pattern ◽  
Cellulose I ◽  
Corn Straw

Cellulose solution and nanocellulose were prepared from corn straw and wheat straw and then used to fabricate an all-cellulose nanocomposites film (ANF). The crystal structure (CS) of ANFs was analyzed by X-ray diffraction (XRD) and Fourier transform infrared spectrometry (FTIR). Cellulose-I and cellulose-II were found to coexist within regenerated cellulose films (RCF) and ANFs. With the change of nanocellulose content, the proportions of cellulose-I and cellulose-II changed. Cellulose transformation was found to depend on the raw material and the preparation method. When cellulose solution was prepared from corn straw that had been extracted, the cellulose type tended to be transformed from cellulose-I to cellulose-II; the proportion of cellulose-I showed a tendency to increase when nanocellulose content exceeded 1.5%. When the dissolved cellulose had been treated by an acid-alkali method, the results did not follow a clear pattern. However, when cellulose solution was prepared from wheat straw, under extraction method, the cellulose type tended to transform from cellulose-I to cellulose-II; under acid-alkali method, cellulose-I did not follow a clear pattern with nanocellulose content. Though the small amount of nanocellulose can’t dominate the content of cellulose-I, it could cause an increase in disorder of the cellulose matrix.

Polarized microbeam FT-IR analysis of single fibers

1996 ◽  
Vol 54 ◽  
pp. 206-207
Author(s):  
Liling Cho ◽  
David L. Wetzel
Keyword(s):  
Molecular Orientation ◽  
Transition Point ◽  
Polymer Fibers ◽  
Single Fiber ◽  
Wire Grid ◽  
Polyester Fibers ◽  
Ft Ir ◽  
Ir Analysis ◽  
The Relationship ◽  
Wire Grid Polarizer

Polarized infrared microscopy has been used for forensic purposes to differentiate among polymer fibers. Dichroism can be used to compare and discriminate between different polyester fibers, including those composed of polyethylene terephthalate that are frequently encountered during criminal casework. In the fiber manufacturering process, fibers are drawn to develop molecular orientation and crystallinity. Macromolecular chains are oriented with respect to the long axis of the fiber. It is desirable to determine the relationship between the molecular orientation and stretching properties. This is particularly useful on a single fiber basis. Polarized spectroscopic differences observed from a single fiber are proposed to reveal the extent of molecular orientation within that single fiber. In the work presented, we compared the dichroic ratio between unstretched and stretched polyester fibers, and the transition point between the two forms of the same fiber. These techniques were applied to different polyester fibers. A fiber stretching device was fabricated for use on the instrument (IRμs, Spectra-Tech) stage. Tension was applied with a micrometer screw until a “neck” was produced in the stretched fiber. Spectra were obtained from an area of 24×48 μm. A wire-grid polarizer was used between the source and the sample.

Synthesis and Evaluation of Levulinic Ester as Biodiesel Additives

2020 ◽  
Vol 71 (8) ◽  
pp. 21-26
Author(s):  
Elena-Emilia Oprescu ◽  
Cristina-Emanuela Enascuta ◽  
Elena Radu ◽  
Vasile Lavric
Keyword(s):  
Maximum Yield ◽  
Strength Distribution ◽  
Point Of View ◽  
Reaction Parameters ◽  
X Ray ◽  
Ethyl Levulinate ◽  
Ft Ir ◽  
Ir Analysis ◽  
Biodiesel Blend ◽  
Acid Strength Distribution

In this study, the SO42-/TiO2-La2O3-Fe2O3 catalyst was prepared and tested in the conversion of fructose to ethyl levulinate . The catalyst was characterized from the point of view of the textural analysis, FT-IR analysis, acid strength distribution, X-ray powder diffraction and pyridine adsorption IR spectra. The influence of the reaction parameters on the ethyl levulinate yield was study. The maximum yield of 37.95% in levulinate esters was obtained at 180 �C, 2 g catalyst and 4 h reaction time. The effect of ethyl levulinate addition to diesel-biodiesel blend in different rates, i.e, 0.5, 1, 2.5, 5 (w.t %) on density, kinematic viscosity and flash point was evaluated and compared with the European specification.

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