scholarly journals Preparation, Characterization and Application of Amorphized Cellulose—A Review

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4313
Author(s):  
Michael Ioelovich
Keyword(s):  
Enzymatic Hydrolysis ◽  
Liquid Ammonia ◽  
Interlayer Spacing ◽  
Amorphous Structure ◽  
Structural Studies ◽  
Amorphous Cellulose ◽  
Optimal Method ◽  
Cellulose Material ◽  
Dry Grinding ◽  
Mercerization Treatment

This review describes the methods of cellulose amorphization, such as dry grinding, mercerization, treatment with liquid ammonia, swelling in solvents, regeneration from solutions, etc. In addition, the main characteristics and applications of amorphized celluloses are discussed. An optimal method for preparing completely amorphous cellulose (CAC) via the treatment of original cellulose material with a cold NaOH/Urea-solvent at the solvent to cellulose ratio R ≥ 5 is proposed. Structural studies show that amorphous cellulose contains mesomorphous clusters with a size of 1.85 nm and specific gravity of 1.49 g/cm3. Furthermore, each such cluster consists of about five glucopyranose layers with an average interlayer spacing of 0.45 nm. Amorphous cellulose is characterized by increased hydrophilicity, reactivity, and enzymatic digestibility. Due to its amorphous structure, the CAC can be used as a promising substrate for enzymatic hydrolysis to produce glucose, which can be applied in biotechnology for growing various microorganisms. In addition, the application of CAC in agriculture is described. A waste-free method for producing amorphous nanocellulose is considered, and the main applications of nanosized amorphous cellulose are discussed.

Synthesis and Properties of Ytterbium Doped C60

1994 ◽  
Vol 349 ◽  
Author(s):  
Stephen H Irons ◽  
P. Klavins ◽  
J.Z. Liu ◽  
M.D. Lan ◽  
R.N. Shelton ◽  
...  
Keyword(s):  
High Temperatures ◽  
Magnetic Relaxation ◽  
Liquid Ammonia ◽  
Stoichiometric Composition ◽  
Amorphous Structure ◽  
Precise Control ◽  
Relaxation Effects ◽  
Magnetization Data ◽  
Long Time

ABSTRACTYtterbium doped C60 (YbxC60) has been synthesized through the use of a liquid ammonia intercalation route. This allows for precise control of the stoichiometric composition. Magnetization data were taken in fields up to 1 Tesla and temperatures between 5 and 300 K on samples with 1≤X≤5. We find the ytterbium introduces significant anisotropies into the system which give rise to long time magnetic relaxation effects that persist to high temperatures. We suggest the existence of an amorphous structure to explain the results.

scholarly journals Synthesis of textured films of hexagonal barium ferrite on Al2O3/Si3N4 amorphous structure

2021 ◽  
Vol 1198 (1) ◽  
pp. 012015
Author(s):  
A. Yu. Mironovich ◽  
V.G. Kostishyn ◽  
I.M. Isaev
Keyword(s):  
Thin Films ◽  
Silicon Nitride ◽  
Aluminum Oxide ◽  
Mechanical Stress ◽  
Barium Ferrite ◽  
Barium Hexaferrite ◽  
Amorphous Structure ◽  
Structural Studies ◽  
Hexagonal Barium Ferrite ◽  
Amorphous Surface

Abstract In this work structural studies of BaFe12O19/Al2O3/Si3N4 thin films with different thicknesses of aluminum oxide and silicon nitride are represented. It is shown that barium hexaferrite crystallizes on the amorphous surface of aluminum oxide with spontaneously formed (00l) uniaxial texture. Microstructural differences in BaFe12O19 films were observed with varying of the thickness of amorphous sublayers, which is explained by the effect of mechanical stress.

scholarly journals Study on the Anti-Biodegradation Property of Tunicate Cellulose

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3071
Author(s):  
Yanan Cheng ◽  
Ajoy Kanti Mondal ◽  
Shuai Wu ◽  
Dezhong Xu ◽  
Dengwen Ning ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Conversion Rate ◽  
Crystallinity Index ◽  
Functional Materials ◽  
Degree Of Polymerization ◽  
Crystalline Size ◽  
Crystalline Cellulose ◽  
Marine Animal ◽  
Amorphous Cellulose ◽  
Cellulose Conversion

Tunicate is a kind of marine animal, and its outer sheath consists of almost pure Iβ crystalline cellulose. Due to its high aspect ratio, tunicate cellulose has excellent physical properties. It draws extensive attention in the construction of robust functional materials. However, there is little research on its biological activity. In this study, cellulose enzymatic hydrolysis was conducted on tunicate cellulose. During the hydrolysis, the crystalline behaviors, i.e., crystallinity index (CrI), crystalline size and degree of polymerization (DP), were analyzed on the tunicate cellulose. As comparisons, similar hydrolyses were performed on cellulose samples with relatively low CrI, namely α-cellulose and amorphous cellulose. The results showed that the CrI of tunicate cellulose and α-cellulose was 93.9% and 70.9%, respectively; and after 96 h of hydrolysis, the crystallinity, crystalline size and DP remained constant on the tunicate cellulose, and the cellulose conversion rate was below 7.8%. While the crystalline structure of α-cellulose was significantly damaged and the cellulose conversion rate exceeded 83.8% at the end of 72 h hydrolysis, the amorphous cellulose was completely converted to glucose after 7 h hydrolysis, and the DP decreased about 27.9%. In addition, tunicate cellulose has high anti-mold abilities, owing to its highly crystalized Iβ lattice. It can be concluded that tunicate cellulose has significant resistance to enzymatic hydrolysis and could be potentially applied as anti-biodegradation materials.

scholarly journals Structural Studies of Enzymatic Hydrolysis of Cellulose by Neutron Scattering and Reflectivity

2009 ◽  
Vol 96 (3) ◽  
pp. 439a
Author(s):  
Michael S. Kent ◽  
Jaclyn K. Murton ◽  
Elizabeth L. Carles ◽  
Frank Zendejas ◽  
Rex Hjelm ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Neutron Scattering ◽  
Structural Studies ◽  
Enzymatic Hydrolysis Of Cellulose ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

scholarly journals Enzymatic Response of Ryegrass Cellulose and Hemicelluloses Valorization Introduced by Sequential Alkaline Extractions

2021 ◽  
Author(s):  
Shao-Fei Sun ◽  
Jing Yang ◽  
Da-Wei Wang ◽  
Hai-Yan Yang ◽  
Shao-Ni Sun ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Physicochemical Properties ◽  
Structural Features ◽  
Natural Resistance ◽  
Fermentable Sugars ◽  
Alkaline Extraction ◽  
Efficient Utilization ◽  
Amorphous Cellulose ◽  
Alkali Extraction ◽  
Molecular Weights

Abstract Background In view of the natural resistance of hemicelluloses in lignocellulosic biomass on bioconversion of cellulose into fermentable sugars, alkali extraction is considered as an effective method for gradually fractionating hemicelluloses and enhancing the bioconversion efficiency of cellulose. In the present study, sequential alkaline extractions were performed on the delignified ryegrass material to achieve high bioconversion efficiency of cellulose and comprehensively investigated the structural feature of hemicellulosic fractions for further application. Results Sequential alkaline extractions removed hemicelluloses from cellulose-rich substrates and degraded part of amorphous cellulose, reducing yields of cellulose-rich substrates from 73.0 to 27.7% and increasing crystallinity indexes of which from 31.7 to 41.0%. Alkaline extraction enhanced bioconversion of cellulose by removal of hemicelluloses and swelling of cellulose, increasing of enzymatic hydrolysis from 72.3 to 95.3%. In addition, alkaline extraction gradually fractionated hemicelluloses into six fractions, containing arabinoxylans as the main polysaccharides and part of β-glucans. Simultaneously, increasing of alkaline concentration degraded hemicellulosic polysaccharides, which resulted in a decreasing their molecular weights from 67510 to 50720 g/mol. Conclusions The present study demonstrated that sequential alkaline extraction conditions had a significant effects on the enzymatic hydrolysis efficiency of cellulose and the investigation of the physicochemical properties of hemicellulose. Overall, the investigation the enzymatic hydrolysis efficiency of cellulose-rich substrates and the structural features of hemicelluloses from ryegrass will provide useful information for the efficient utilization of cellulose and hemicelluloses in biorefineries.

Sign in / Sign up

Export Citation Format

Share Document