Evaluation of changes in cellulose micro/nanofibrils structure under chemical and enzymatic pre-treatments

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jordão Cabral Moulin ◽  
Alisson Farley Soares Durães ◽  
Matheus Cordazzo Dias ◽  
Luiz Eduardo Silva ◽  
Allan de Amorim dos Santos ◽  
...  
Keyword(s):  
Average Diameter ◽  
Raman Microspectroscopy ◽  
Degree Of Polymerization ◽  
Pulp Fibers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cellulose Structure ◽  
Pre Treatment

Abstract The objective of the present work was to evaluate the use of Raman microspectroscopy analysis to assess changes in cellulose micro/nanofibril structure from fibers subjected to different pre-treatments. Pulp fibers were pre-treated with 5 wt% NaOH for 2 h, 10 wt% NaOH for 1 h, and endoglucanase-type enzymes to improve nanofibrilation. After the pre-treatments, the fibers were mechanically fibrillated to produce cellulose micro/nanofibrils, which were made into films to be analyzed. Fibers pre-treated with 5 wt% NaOH produced 59% micro/nanofibrils with average diameter less than 30 nm, for Eucalyptus, and 46% of micro/nanofibrils, with the same diameter, for Pinus. However, the enzymatic pre-treatment was the most efficient, resulting in 83% of micro/nanofibrils for Eucalyptus and 78% for Pinus. This corroborates with the lowest values of the 1.096/2.896 ratio and degree of polymerization, indicating chain shortening in cellulose. X-ray diffraction and Raman microspectroscopy crystallinity results presented similar tendencies, with increased crystallinity caused by all pre-treatments, being 5 wt% NaOH for 2 h the highest, with 70%, for Eucalyptus and Pinus. Enzymatic pre-treatment has produced the best fibrillation and greater crystallinity. The present work has shown a reliable way of assessing cellulose structure using Raman microspectroscopy.

Influence of High Current Pulsed Electron Beam Irradiation on Ni-P Electroless Plating

2011 ◽  
Vol 299-300 ◽  
pp. 77-81
Author(s):  
Yang Xu ◽  
Sheng Zhi Hao ◽  
Xiang Dong Zhang ◽  
Min Cai Li ◽  
Chuang Dong
Keyword(s):  
Electroless Plating ◽  
Electron Beam Irradiation ◽  
Xrd Analysis ◽  
High Current ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pulsed Electron Beam ◽  
6063 Aluminum Alloy ◽  
Pre Treatment ◽  
Better Than

The surface irradiation of 6063 aluminum alloy by high current pulsed electron was conducted with the aim of replacing the complicated pre-treatment in the processes of electroless plating. To explore the microstructure changes, optical metallography, SEM (scanning electron microscope), XRD (X-ray diffraction) analyses were carried out, and the sliding tests were used for the detection of wear resistance. It was concluded that the HCPEB irradiation could replace the pre-treatment of aluminum substrate as required in conventional electroless plating with a decreased surface roughness of Ni-P alloy plating layer. The plates exhibited an amorphous microstructure as demonstrated by XRD analysis. The plates, produced with the routine of HCPEB irradiation, activation and electroless plating possess, also exhibited good quality, even better than that of conventional electroless plating technique.

Study on Influence of Silicate Morphology Based on pH Value

2012 ◽  
Vol 454 ◽  
pp. 324-328
Author(s):  
Yan He ◽  
Ya Jing Liu ◽  
Yong Lin Cao ◽  
Li Xia Zhou
Keyword(s):  
Silicic Acid ◽  
Ph Value ◽  
Colorimetric Method ◽  
Absorption Spectrometry ◽  
Degree Of Polymerization ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
The Stability

Infra-red absorption spectrometry, X-ray diffraction observations and characterization tests based on silicon molybdenum colorimetric method were used to investigate the optimal pH value controlling the stability of the silicic acid form. The experiment process was done by using sodium silicate as raw material. The results showed that the solution of silicate influenced the polymerization. The active silicic acid solution with a certain degree of polymerization was obtained by controlling the pH values.

Monodisperse Fe3O4/Fe Core/Shell Nanoparticles with Enhanced Magnetic Property

2011 ◽  
Vol 306-307 ◽  
pp. 410-415
Author(s):  
Li Sun ◽  
Fu Tian Liu ◽  
Qi Hui Jiang ◽  
Xiu Xiu Chen ◽  
Ping Yang
Keyword(s):  
Average Diameter ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Shell Particles ◽  
Core Shell Nanoparticles

Core/shell type nanoparticles with an average diameter of 20nm were synthesized by chemical precipitation method. Firstly, Monodisperse Fe3O4 nanoparticles were synthesized by solvethermal method. FeSO4ž7H2O and NaBH4 were respectively dissolved in distilled water, then moderated Fe3O4 particles and surfactant(PVP) were ultrasonic dispersed into the FeSO4ž7H2O solution. The resulting solution was stirred 2 h at room temperature. Fe could be deposited on the surface of monodispersed Fe3O4 nanoparticles to form core-shell particles. The particles were characterized by using various experimental techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), AGM and DTA. The results suggest that the saturation magnetization of the nanocomposites is 100 emu/g. The composition of the samples show monodisperse and the sides of the core/shell nanoparticles are 20-30nm. It is noted that the formation of Fe3O4/Fe nanocomposites magnetite nanoparticles possess superparamagnetic property.

Preparation and Photocatalytic Properties of Rod-Shaped TiO2 Based on Salix Fiber

2014 ◽  
Vol 609-610 ◽  
pp. 250-254
Author(s):  
Ya Bin Li ◽  
Jin Tian Huang ◽  
Yan Fei Pan
Keyword(s):  
Photocatalytic Performance ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Nanocomposite Structure ◽  
X Ray ◽  
Infrared Spectrometer ◽  
Ft Ir ◽  
Degradation Of Methyl Orange ◽  
Scanning Electron

In the paper, the TiO2nanomaterials adopted the microcrystalline cellulose as the template by the template method and sol-gel method was prepared. Through the infrared spectrometer (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD), the surface morphology, composition and the type of the samples were characterized respectively. The influence of the macro morphology of TiO2photocatalytic performance to use the reaction of decolorization and degradation of methyl orange as model was analyzed. The results showed that TiO2which was produced by the template of sallix fiber was Rod-shaped and the average diameter size of nanocomposite structure was 20.592 nm, which can provide a new method of producing other morphology of TiO2.

Surface analytical study of uranium exposed to low pressures of hydrogen at ∼ 80°C

2012 ◽  
Vol 1444 ◽  
Author(s):  
Robert M. Harker ◽  
Afiya H. Chohollo
Keyword(s):  
Room Temperature ◽  
Analytical Study ◽  
Treatment Cycle ◽  
X Ray Diffraction ◽  
Standard Samples ◽  
X Ray ◽  
Surface Precipitation ◽  
Pre Treatment ◽  
Low Pressures ◽  
Scanning Electron

ABSTRACTIdentical samples of uranium coupons were prepared and each exposed to hydrogen for different times (where this time is significantly less than a classically understood ‘induction time’). Samples were prepared from rolled depleted uranium stock: as-received oxide was removed on all surfaces and two faces (~12x12 mm) were polished to a sub-micron standard. Samples were individually taken through a Vacuum Thermal Pre-Treatment cycle from room temperature to 200°C to the reaction temperature (80°C) over 40 hours and subsequently exposed to 10 mbar O2 for 24 hours. After O2 was removed, the samples were exposed to hydrogen for pre-determined times of up to 48 minutes. Examination of the samples by Scanning Electron Microscopy (SEM) has, as expected, identified small features protruding from the surface believed to have been caused by sub-surface precipitation of UH3. In general these features are circular and isolated from each other, have a diameter of less than 3μm and appear as either ‘flat-topped’ or ‘domed’ morphology. In addition, longer time exposure samples show a predominance of ‘area attack’ where coalesced sub-surface precipitation appears to be confined to particular metal grains. X-Ray Diffraction (XRD) data show an increase in the quantity of UH3 with time.

Sb-rich nanoinclusions in an AlGaAsSb metamaterial

MRS Advances ◽  
2019 ◽  
Vol 4 (5-6) ◽  
pp. 277-284
Author(s):  
Nikolay A. Bert ◽  
Vladimir V. Chaldyshev ◽  
Nikolay A. Cherkashin ◽  
Vladimir N. Nevedomskiy ◽  
Valery V. Preobrazhenskii ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Filling Factor ◽  
Local Thermodynamic Equilibrium ◽  
Average Diameter ◽  
Formation Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Self Organized ◽  
Transmission Electron ◽  
The Matrix

ABSTRACTWe studied the microstructure of Al0.28Ga0.72As0.972Sb0.028 metamaterials containing a developed array of AsSb nanoinclusions. The AlGaAsSb films were grown by low-temperature molecular-beam epitaxy followed by high-temperature annealing at 750°C. The process resulted in an array of self-organized AsSb nanonclusions with an average diameter of 15 nm. The volume filling factor was about 0.003. Using transmission electron microscopy and x-ray diffraction we showed that the nanoinclusions have A7-type rhombohedral atomic structure with the following orientation in the matrix (0003)p || {111}m and [-2110]p || 〈220〉m, where p and m indices indicate the AsSb precipitate and AlGaAsSb matrix, correspondingly. The nanoinclusions appeared to be strongly enriched by antimony (more than 90 atomic %), whereas the Sb content in the AlGaAsSb matrix was 2.8 atomic %. The strong enrichment of the inclusion with Sb resulted from the local thermodynamic equilibrium between the solid AlGaAsSb matrix and AsSb inclusions which became liquid at a formation temperature of 750°C.

Preparation of PCL/PVP/Ag Nanofiber Membranes by Electrospinning Method

2012 ◽  
Vol 268-270 ◽  
pp. 580-583 ◽  
Author(s):  
Yong Tang Jia ◽  
Cui Wu ◽  
Feng Chun Dong ◽  
Gang Huang ◽  
Xian Hua Zeng
Keyword(s):  
Silver Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Composite Nanofibers ◽  
Average Diameter ◽  
Vinyl Pyrrolidone ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrospinning Method ◽  
Nanofiber Membranes ◽  
Poly Vinyl Pyrrolidone

The composite nanofiber membranes of poly (ε-caprolactone)/poly(vinyl pyrrolidone) (PCL/PVP) containing silver nanoparticles were prepared by electrospinning method. The morphology of composite nanofibers was characterized by scanning electron microscopy (SEM). The silver nanoparticles on the electrospun fibers were characterized by X-Ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The contact angle and water uptake of PCL/PVP/Ag nanofiber membranes were measured. The SEM photos indicated that the average diameter of the fibers was significantly decreased with the addition of silver nanoparticles. The X-Ray images showed that Ag nanoparticles were distributed on the surface of nanofiber membranes. When the PVP mole ratio was higher than 15%, the nanofiber membranes showed good hydrophilic property. The PCL/PVP/Ag nanofiber membranes could be applied to prepare wound dressing.

Synthesis, Morphology Control and Luminescent Properties of Rare Earth Ion-Doped CaWO4 Microstructures

2016 ◽  
Vol 16 (4) ◽  
pp. 4029-4034 ◽  
Author(s):  
Chunxia Liu ◽  
Lixia Yang ◽  
Dan Yue ◽  
Mengnan Wang ◽  
Lin Jin ◽  
...  
Keyword(s):  
Rare Earth ◽  
Uv Light ◽  
Luminescent Properties ◽  
Average Diameter ◽  
Rare Earth Ions ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
Rare Earth Ion ◽  
X Ray ◽  
Facile Hydrothermal Route

Rare earth ions (Tb3+, Eu3+) doped CaWO4 microstructures were synthesized by a facile hydrothermal route without using any templates and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectrum. The results indicate that the asprepared samples are well crystallized with scheelite structure of CaWO4, and the average diameter of the microstructures is 2∼4 μm. The morphology of CaWO4:Eu3+ microstructures can be controllably changed from microspheres to microflowers through altering the doping concentration of Eu3+ from 3% to 35%, and the microflowers are constructed by a number of CaWO4:Eu3+ nanoflakes. Under the excitation of UV light, the emission spectrum of CaWO4:Eu3+ is composed of the characteristics emission of Eu3+ 5D0-7FJ (J = 1, 2, 3, 4) transitions, and that of CaWO4:Tb3+ is composed of Tb3+ 5D4-7FJ (J = 6, 5, 4, 3) transitions. Both of the optimal doping concentrations of Tb3+ and Eu3+ in CaWO4 microstructures are about 5%.

Effect Addition of Octadecylamine Modified Clay (ODA-MMT) to Polylactide/Polycaprolactone (PLA/PCL) Blend

2011 ◽  
Vol 364 ◽  
pp. 317-321 ◽  
Author(s):  
Siti Zulaiha Hairaldin ◽  
Wan Md Zin Wan Yunus ◽  
Nor Azowa Ibrahim
Keyword(s):  
Polymer Nanocomposite ◽  
Average Diameter ◽  
Sem Analysis ◽  
Clay Nanocomposites ◽  
Melt Blending ◽  
X Ray Diffraction ◽  
X Ray ◽  
Blending Method ◽  
Sem Micrograph ◽  
Internal Mixer

In this study, Octadecylamine Modified montmorillonites (ODAMMT) were used to prepare polylactide/polycaprolactone (PLA/PCL) clay nanocomposites. PLA and PCL were blend using an internal mixer by melt blending method. The other sample was blend with natrium monmorillonite (NaMMT) and Octadecylamine modified monmorillonite to produce PLA/PCL-NaMMT and PLA/PCL-ODAMMT. To characterize the polymer nanocomposite, X-ray diffraction (XRD), FTIR and SEM analysis were conducted. Comparison of morphology were made up between neat PLA/PCL, PLA/PCL with presence of of montmorillonite and octadecylamine modified monmorillonite respectively based on SEM micrograph. The number-average diameter was calculated for PLA/PCL, PLA/PCL-NaMMT, and PLA/PCL-ODAMMT.

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