scholarly journals Facile Method to Tune the Particle Size and Thermal Stability of Magnetite Nanoparticles

2015 ◽  
Author(s):  
Loushambam H. Singh ◽  
Sudhanshu S. Pati ◽  
Maria J. A. Sales ◽  
Edi M. Guimarães ◽  
Aderbal C. Oliveira ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Particle Size ◽  
Magnetite Nanoparticles ◽  
Thermal Stability Of

Thermal stability of nanocrystalline WC–Co powder synthesized by using mechanical milling at low temperature

2001 ◽  
Vol 16 (2) ◽  
pp. 478-488 ◽  
Author(s):  
Jianhong He ◽  
Leoanardo Ajdelsztajn ◽  
Enrique J. Lavernia
Keyword(s):  
Thermal Stability ◽  
Particle Size ◽  
Mechanical Milling ◽  
Gradual Increase ◽  
Thermal Exposure ◽  
X Ray Diffraction ◽  
Cryomilled Powder ◽  
X Ray ◽  
Increasing Temperature ◽  
Thermal Stability Of

Nanostructured WC–18% Co powder was synthesized by using cryogenic mechanical milling, and the thermal stability of the nanostructured powder was investigated in detail. The results indicated that the as-synthesized WC–18% Co powder had an average WC particle size of 25 nm. Growth of WC particles occurred above 873 K; however, the average WC particle size remained smaller than 100 nm in the powder isothermally heated for 4 h at 1273 K. Thermal exposure in air at T < 623 K did not result in significant oxidation of the cryomilled powder. The thermal exposure did promote the formation of WO2 and WO3 oxides. The Co6W6C phase was detected by x-ray diffraction in the powder heated in nitrogen at 1273 K, and the phases associated with decarburization of WC, such as W2C, W3C phases, were not observed. With increasing temperature, the dissolution of W and C elements in the Co matrix led to a gradual increase in {111} crystallographic plane spacing, eventually leading to the formation of an amorphous phase.

ROLE OF MOLYBDENUM TRIOXIDE ON THERMAL STABILITY OF POLYANILINE NANOCOMPOSITE

2012 ◽  
Vol 11 (03) ◽  
pp. 1250025
Author(s):  
P. SUJA PREMA RAJINI ◽  
R. MURUGESAN ◽  
S. PERUMAL
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Particle Size ◽  
Metal Oxide ◽  
Molybdenum Trioxide ◽  
Spectral Studies ◽  
Average Particle ◽  
Weight Loss Step ◽  
The Third ◽  
Thermal Stability Of

Molybdenum trioxide (MoO3) grains were coated with conducting organic polymer of polyaniline. The as-prepared nanocomposite samples were characterized by Fourier transformed infrared (FTIR) spectra, X-ray diffraction (XRD) and Thermogravimetry (TGA). The XRD curves shows that, [Formula: see text] have high crystallinity due to the presence of large number of sharp peaks. From the XRD pattern the particle size is evaluated by using Debye-Scherrer's formula and the average particle size of [Formula: see text] and [Formula: see text] nanocomposites are found to be 46 and 32 nm, respectively. This is clearly observed that the condensed particle size of nanocomposite materials is due to the insertion of metal oxide of molybdenum. The incorporation of metal oxide of MoO3 in polyaniline (Pani) is confirmed by FTIR spectral studies. After de-doping, the characteristic peaks of Pani for all the Pani materials are almost same. This is due to the leaching of metal oxide of MoO3 from Pani. From these observations it is noted that doping–dedoping can also take place in inorganic metal oxides. The thermogram showed a three-step degradation process. The first weight loss step was due to the removal of physisorbed water molecules and moisture. The second minor weight loss step was associated with the removal of dopant from Pani backbone and the slight degradation of benzenoid structure of Pani and their thermal stability is enhanced. The third weight loss step was ascribed to the degradation of quinoid form of Pani. This confirmed the thermal stability of [Formula: see text] nanocomposite system. After degradation above 1000°C, the Pani with MoO3 showed a remaining weight of 8%. This confirmed that incorporation of metal oxide in the Pani nanocomposites is 8%. The enhancement of thermal stability is due to the intercalation of Pani chains into MoO3 in first two step degradation, which is further supported by FTIR and XRD reports. The third step degradation of Pani with MoO3 nanocomposite is loosely bound in organic and inorganic part. Therefore, the organic part is easily decomposed.

Conductivity and Thermal-Stability of 5-Sulfosalicylic Acid Sodium Doped Polypyrrole

2010 ◽  
Vol 428-429 ◽  
pp. 579-582 ◽  
Author(s):  
Fu Fang Zhou ◽  
Bao Gai Zhai ◽  
Chun Xu Pan ◽  
Yuan Ming Huang
Keyword(s):  
Thermal Stability ◽  
Particle Size ◽  
Laser Light ◽  
Dopant Concentration ◽  
Laser Light Scattering ◽  
Probe Laser ◽  
Sulfosalicylic Acid ◽  
Wide Range ◽  
Thermal Stability Of

By varying the dopant-to-pyrrole ratio in a wide range from 0 to 60% a series of 5-sulfosalicylic acid sodium doped polypyrrole was synthesized in situ in aqueous solution with ferric chloride as the oxidant. The resulting polypyrroles were characterized with the four-probe, laser light scattering and thermo-gravimetry analysis, differential thermal analysis, respectively. Our results indicate that the particle size plays a determinative role to tune the conductivity in the studied range of dopant concentration; and this series of polypyrrole with size-tuned-conductivity exhibits little less thermal-stability although its size and conductivity changes simultaneously and acutely with the dopant concentration. The association of the conductivity with particle size was interpreted in terms of a theoretical model proposed by Baughman and Shacklelette.

Dependence of thermal stability of lithiated Si on particle size

2016 ◽  
Vol 335 ◽  
pp. 38-44 ◽  
Author(s):  
Chao Li ◽  
Tongfei Shi ◽  
Decheng Li ◽  
Hideya Yoshitake ◽  
Hongyu Wang
Keyword(s):  
Thermal Stability ◽  
Particle Size ◽  
Thermal Stability Of

scholarly journals PREPARATION OF CASTOR-BASED POLYURETHANE COMPOSITES FILLED WITH WASTE CARBON TYRES (WCT) AS GROUTING MATERIAL

2020 ◽  
Vol 82 (5) ◽  
Author(s):  
Nur Izzah Atirah Mat Hussain ◽  
Noor Najmi Bonnia ◽  
Radin Siti Fazlina Nazrah Hirzin ◽  
Ernie Suzana Ali ◽  
Suzana Ratim
Keyword(s):  
Thermal Stability ◽  
Particle Size ◽  
Reaction Time ◽  
Compression Strength ◽  
Foam Cell ◽  
Polyurethane Composite ◽  
Grouting Material ◽  
Polyurethane Composites ◽  
Uniform Particle Size ◽  
Thermal Stability Of

This research focused on the fabrication of castor-based polyurethane composite (CPUC) filled with waste carbon tyres (WCT) with particle size of 200 µm that acts as reinforcing filler. WCT was first sieved using a sieving machine to obtain uniform particle size. WCT loading was varied at 0wt%, 2wt%, 4wt% and 6wt%. The effect of WCT loading in CPUC was evaluated based on their foam reaction time, apparent density, rheology, compression strength, morphology and thermal properties. The foam reaction time of CPUC achieved was in the range of industrial PU grout’s properties. The rheology index and compression strength of CPUC decreased with increasing WCT loading. CPUC with 2wt% of WCT loading achieved the optimum compression strength where it increased from 2.58 MPa to 3.39 MPa with the improvement of 31.40% compared to neat PU. FESEM micrograph showed that CPUC consists of closed foam cell indicating the rigidity of the CPUC. The addition of 2wt% of WCT resulted in achieving the optimum thermal stability of CPUC where CPUC2 had the highest char residue content. The high residue content indicated that CPUC2 had the lowest decomposition of elements as WCT acted as heat barrier in CPUC matrix thus increasing the thermal stability of CPUC2.

scholarly journals Physicochemical characterization of mesquite flours

2018 ◽  
Author(s):  
S. Sandoval Torres ◽  
L. Reyes López ◽  
L. Méndez Lagunas ◽  
J. Rodríguez Ramírez ◽  
G. Barriada Bernal
Keyword(s):  
Thermal Stability ◽  
Particle Size ◽  
Physicochemical Characterization ◽  
Chemical Properties ◽  
Sorption Isotherms ◽  
Nutritional Composition ◽  
Gluten Free ◽  
Sieving Process ◽  
Thermal Stability Of

Ethnic foods are healthy products interesting for the new societies. Mesquite flour offers another option for making gluten-free recipes as part of a diet for people with celiac disease. The physicochemical properties of mesquite flours (Prosopis laevigata) were characterized. The mesquite pods were dried at 60°C, 15% RH and 2 m/s airflow; then a grinding and sieving process were applied. The nutritional composition and the sorption isotherms were obtained at 30, 35, 40 and 45°C  for  water activities of 0.07-0.9. The particle-size distribution, morphology and thermal stability of the flours were determined by different methods. Keywords: Mesquite Flours; drying; isotherms; chemical properties; morphology

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