Process Optimization for Nanocrystalline Cellulose Production from Microcrystalline Cellulose

2011 ◽  
Vol 1312 ◽  
Author(s):  
Christophe Danumah ◽  
Hicham Fenniri

ABSTRACTA process optimization has been developed for obtaining nanocrystalline cellulose (NCC) by acid hydrolysis of commercially available microcrystalline cellulose (MCC) in high yield (~ 40-50%). This method was based on control of key parameters such as the rate of addition of sulfuric acid solution to the MCC/water suspension, the mixing speed, the volume of collected NCC suspensions and the volume ratio of NCC suspension to water during dialysis. The resulting NCC products were characterized by x-ray diffraction (XRD), thermogravimetric analysis (TGA), elemental analysis (EA), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Electron microscopy results showed that the rod-shaped NCC had lengths and widths of about 40-400 nm and 5-40 nm, respectively.

2005 ◽  
Vol 106 ◽  
pp. 117-122 ◽  
Author(s):  
Izabela Szafraniak ◽  
Dietrich Hesse ◽  
Marin Alexe

Self-patterning presents an appealing alternative to lithography for the production of arrays of nanoscale ferroelectric capacitors for use in high density non-volatile memory devices. Recently a self-patterning method, based on the use of the instability of ultrathin films during hightemperature treatments, was used to fabricate nanosized ferroelectrics. This paper reports the use of the method for the preparation of PZT nanoislands on different single crystalline substrates - SrTiO3, MgO and LaAlO3. Moreover, a multi-step deposition procedure in order to control lateral the dimension of the crystals was introduced. The nanostructures obtained were studied by atomic force microscopy, scanning electron microscopy and X-ray diffraction.


2012 ◽  
Vol 730-732 ◽  
pp. 257-262
Author(s):  
Bruno Nunes ◽  
Sergio Magalhães ◽  
Nuno Franco ◽  
Eduardo Alves ◽  
Ana Paula Serro ◽  
...  

Aiming to improve the nanotribological response of Si-based materials we implanted silicon wafers with different fluences of iron ions (up to 2x1017 cm-2). Implantation was followed by annealing treatments at temperatures from 550°C to 1000°C. The implanted surfaces were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM) and wettability tests. Then, samples were submitted to AFM-based nanowear tests. We observe an increase of both hidrophobicity and and wear resistance of the implanted silicon, indicating that ion implantation of Si can be a route to be deeper explored in what concerns tribomechanical improvement of Si.


2020 ◽  
Vol MA2020-02 (24) ◽  
pp. 1750-1750
Author(s):  
Andrea Quintero Colmenares ◽  
Patrice Gergaud ◽  
Jean-Michel Hartmann ◽  
Vincent Delaye ◽  
Nicolas Bernier ◽  
...  

1998 ◽  
Vol 535 ◽  
Author(s):  
P. Kopperschmidt ◽  
S T. Senz ◽  
R. Scholz ◽  
G. Kästner ◽  
U. Gösele ◽  
...  

AbstractWe realized “compliant” substrates in the square centimeter range by twist-wafer bonding of an (100) GaAs handle wafer to another (100) GaAs wafer with a several nm thick epitaxially grown GaAs layer followed by an appropriate back-etch procedure. The twist angle between the two GaAs wafers was chosen between 4 and 15 degrees. The twisted layers were characterized by area scanned X-ray diffraction, optical and electron microscopy and atomic force microscopy. Occasionally we observed regions showing pinholes in the transferred thin twistbonded GaAs layer.After epitaxial deposition of 300 nm InP and InGaAs films with different degrees of mismatch on these substrates, transmission electron microscopy revealed grains which are epitaxially oriented to either the substrate or the twist-bonded layer. The grain boundaries between the twisted and untwisted grains probably collect threading dislocations, thus reducing their density in the areas free of boundaries.


2015 ◽  
Vol 821-823 ◽  
pp. 213-216
Author(s):  
S.M. Ryndya ◽  
N.I. Kargin ◽  
A.S. Gusev ◽  
E.P. Pavlova

Silicon carbide thin films were obtained on Si (100) and (111) substrates by means of vacuum laser ablation of α-SiC ceramic target. The influence of substrate temperature on composition, structure and surface morphology of experimental samples was examined using Rutherford backscattering spectrometry (RBS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), conventional and high-resolution transmission electron microscopy (TEM/HRTEM), atomic force microscopy (AFM), selected area electron diffraction (SAED) and X-ray diffraction (XRD) methods.


2008 ◽  
Vol 8 (8) ◽  
pp. 4127-4131 ◽  
Author(s):  
G. S. Okram ◽  
Kh. Namrata Devi ◽  
H. Sanatombi ◽  
Ajay Soni ◽  
V. Ganesan ◽  
...  

Nanocrystalline nickel powders were prepared with grain size 'd' in the range 40–100 nm diameters through polyol method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used for characterization. XRD of the prepared samples consistently matched with standard fcc structure of nickel without any impurity peak. Detailed analysis and calculations using Scherrer equation for (111) peak revealed systematic increase in line width and peak shifting towards lower diffraction 2θ angles with decrease in nickel to ethylene glycol mole ratio. Different values of d estimated from various peaks of each sample suggested associated microstrains in the nanograins. Values of d estimated from X-ray diffraction patterns were compared with those obtained from atomic force microscopy and scanning electron microscopy results, and discussed. Observed lattice expansion is explained, on the basis of a theoretical model of linear elasticity.


2008 ◽  
Vol 40 (3) ◽  
pp. 271-281
Author(s):  
Marquez Aguilar ◽  
M. Vlasova ◽  
M.C. Reséndiz-González ◽  
M. Kakazey ◽  
Mayorga Cruz ◽  
...  

The influence of continuous IR laser irradiation (? = 1064 nm, P = 240 mW) on SiC-MoSi2 composite ceramics was investigated by X-ray diffraction, electron microscopy, atomic force microscopy, and X-ray microanalysis. The irradiation of specimens was carried out in air. It was established that, due to heating of the surface under laser irradiation, oxidation of SiC and MoSi2 and sublimation of SiO (SiO2) and MoO3 take place. Depending on the content of the components in the ceramics and the irradiation time, SiO2 or MoO3 layers form on the surface or disappear from it. For a long irradiation time, the oxidation and cleaning of the surface (sublimation of oxides) are cyclic in character.


2019 ◽  
Vol 25 (4) ◽  
pp. 45-54 ◽  
Author(s):  
Noor Sabih Majeed ◽  
Basma A. Abdulmajeed ◽  
Anwar Khudhur Yaseen

Recently the use of nanofluids represents very important materials. They are used in different branches like medicine, engineering, power, heat transfer, etc. The stability of nanofluids is an important factor to improve the performance of nanofluids with good results. In this research two types of nanoparticles, TiO2 (titanium oxide) and γ-Al2O3 (gamma aluminum oxide) were used with base fluid water. Two-step method were used to prepare the nanofluids. One concentration 0.003 vol. %, the nanoparticles were examined. Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and X-ray diffraction (XRD) were used to accomplish these tests. The stability of the two types of nanofluids is measured by zeta potential and UV-vis spectrophotometer. The results showed that γ-Al2O3/water has more stable than TiO2/ water for the same period of time.  


2008 ◽  
Vol 8 (4) ◽  
pp. 1757-1761 ◽  
Author(s):  
Ajeet Kaushik ◽  
Jitendra Kumar ◽  
M. K. Tiwari ◽  
R. Khan ◽  
B. D. Malhotra ◽  
...  

Polyaniline (PANI)–ZnO nanocomposite thin film has been successfully fabricated on glass substrates by using vacuum deposition technique. The as-grown PANI–ZnO nanocomposite thin films have been characterized using X-ray diffraction, Scanning Electron Microscopy, Atomic Force Microscopy, UV-visible spectrophotometer and Fourier Transform Infrared (FTIR) spectroscopy, respectively. X-ray diffraction of as-grown film shows the reflection of ZnO nanoparticles along with a broad peak of PANI. The surface morphology of nanocomposite films has been investigated using scanning electron microscopy and atomic force microscopy. The hypsochromic shift of the UV absorption band corresponding to π–π* transition in polymeric chain of PANI and a band at 504 cm –1 due to ZnO nanoparticles has been observed in the FTIR spectra. The hydrogen bonding between the imine group of PANI and ZnO nanoparticle has been confirmed from the presence of the absorbance band at 1151 cm–1 in the FTIR spectra of the nanocomposite thin films.


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