scholarly journals Polystyrene/Montmorillonite Nanocomposites: Study of the Morphology and Effects of Sonication Time on Thermal Stability

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Mashael Alshabanat ◽  
Amal Al-Arrash ◽  
Waffa Mekhamer
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Solution Method ◽  
Sonication Time ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Polystyrene Matrix ◽  
Before And After ◽  
Silicate Layers ◽  
Thermal Stability Of

Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT) were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB) is used to modify the montmorillonite clay after saturating its surface with Na+ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA). The results show clear improvement, and the effects of sonication time are noted.

Thermal Stability and Aging Characteristics of HNBR/Clay Nanocomposites in Air, Water and Oil at Elevated Temperature

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Huang Anmin ◽  
Wang Xiaoping ◽  
Jia Demin ◽  
Li Yanmei
Keyword(s):  
Thermal Stability ◽  
Elevated Temperature ◽  
Physical And Mechanical Properties ◽  
Clay Nanocomposites ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Roll Mill ◽  
Before And After ◽  
Thermal Stability Of ◽  
Aging In Air

AbstractHydrogenated nitrile rubber (HNBR)/clay nanocomposites are prepared using conventional two-roll mill mixing technique. The structure and morphology of nanocomposites are characterized using wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). Both intercalated and exfoliated clay structures are observed in HNBR/clay nanocomposites. The thermal stability of the nanocomposites is studied using thermogravimetric analysis (TGA) and TGA-Fourier transform infrared (FTIR) spectroscopy. The effect of organoclay on physical and mechanical properties of HNBR vulcanizates before and after aging in air, water and oil at 178 °C is also investigated. It is found that adding organoclay in HNBR elastomer greatly improves material thermal stability and aging performance in different medium at elevated temperature.

Synthesis, Characterization and Thermal Analysis of Rod-Shaped Polyaniline-Barium Ferrites Nanocomposites

2010 ◽  
Vol 150-151 ◽  
pp. 386-390
Author(s):  
Yuan Xun Li ◽  
Ying Li Liu ◽  
Huai Wu Zhang ◽  
Wei Wei Ling
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Barium Ferrite ◽  
In Situ Polymerization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Barium Ferrites ◽  
Thermal Stability Of

The rod-shaped polyaniline (PANI)-barium ferrite nanocomposites were synthesized by in situ polymerization of aniline in the presence of BaFe12O19 nanoparticles with diameters of 60-80 nm. The composites obtained were characterized by infrared spectra (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The thermal stability and the composition of the composites were investigated by TG-DTG analysis. The results indicate that the thermal stability of the composites is higher than that of the pure PANI which can be attributed to the interactions existed between PANI chains and ferrite particles.

Microstructure and Thermal Stability of Ultra Fine Grained Mg and Mg-Gd Alloys Prepared by High-Pressure Torsion

2005 ◽  
Vol 482 ◽  
pp. 183-186 ◽  
Author(s):  
Jakub Čížek ◽  
Ivan Procházka ◽  
Bohumil Smola ◽  
Ivana Stulíková ◽  
Radomír Kužel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
High Pressure ◽  
Positron Lifetime ◽  
High Pressure Torsion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fine Grained ◽  
Transmission Electron ◽  
Thermal Stability Of

Bulk samples of pure Mg and Mg-Gd alloys were prepared by high-pressure torsion (HPT). The HPT made samples exhibit ultra fine grained (UFG) structure with grain size around 100 nm. Results of microstructure investigations of the UFG samples obtained by positron lifetime (PL) spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD) are presented. In particular, lattice defects introduced by HPT were characterized. The data obtained at atomistic level are compared with macroscopic properties given by microhardness measurements.

Microstructure and thermal stability of an ultrafine Al/Al2O3 composite

2003 ◽  
Vol 18 (2) ◽  
pp. 272-278 ◽  
Author(s):  
Zhiqing Yang ◽  
Lianlong He ◽  
Ji Chen ◽  
Hongtao Cong ◽  
Hengqiang Ye
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Transmission Electron Microscopy ◽  
Grain Growth ◽  
High Strength ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Al2o3 Composite ◽  
Almost All ◽  
Thermal Stability Of

Studies were carried out on the microstructure and thermal stability of an ultrafine Al/Al2O3 composite with high strength and low density. Transmission electron microscopy indicated that Al2O3 shells remained undeformed below 550 °C, which limited grain growth of Al. Both transmission electron microscopy and x-ray diffraction analysis indicated that no obvious grain growth of Al with time occurred upon annealing at 620 °C. After almost all the alumina shells were destroyed following annealing at 620 °C, the Al2O3 fragments with various morphologies distributed in the material could still limit the migration of Al grain boundaries to increase the thermal stability of the material. After Al melted and resolidified, the grain sizes of Al were still about 200 nm. The bulk composite sample showed good dimensional stability. Even if the Al grains melted, the network of Al2O3 fragments kept the sample from deforming due to the wetting of Al2O3 network with liquid Al.

scholarly journals Thermal treatment of magnetite nanoparticles

2015 ◽  
Vol 6 ◽  
pp. 1385-1396 ◽  
Author(s):  
Beata Kalska-Szostko ◽  
Urszula Wykowska ◽  
Dariusz Satula ◽  
Per Nordblad
Keyword(s):  
Thermal Stability ◽  
Thermal Treatment ◽  
Magnetite Nanoparticles ◽  
Surface Characteristics ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Before And After ◽  
Thermal Stability Of

This paper presents the results of a thermal treatment process for magnetite nanoparticles in the temperature range of 50–500 °C. The tested magnetite nanoparticles were synthesized using three different methods that resulted in nanoparticles with different surface characteristics and crystallinity, which in turn, was reflected in their thermal durability. The particles were obtained by coprecipitation from Fe chlorides and decomposition of an Fe(acac)3 complex with and without a core–shell structure. Three types of ferrite nanoparticles were produced and their thermal stability properties were compared. In this study, two sets of unmodified magnetite nanoparticles were used where crystallinity was as determinant of the series. For the third type of particles, a Ag shell was added. By comparing the coated and uncoated particles, the influence of the metallic layer on the thermal stability of the nanoparticles was tested. Before and after heat treatment, the nanoparticles were examined using transmission electron microscopy, IR spectroscopy, differential scanning calorimetry, X-ray diffraction and Mössbauer spectroscopy. Based on the obtained results, it was observed that the fabrication methods determine, to some extent, the sensitivity of the nanoparticles to external factors.

Formation and Thermal Stability of Nd0.32Y0.68Si1.7 Layers Formed by Channeled Ion Beam Synthesis

1998 ◽  
Vol 514 ◽  
Author(s):  
M. F. Wu ◽  
A. Vantomne ◽  
S. Hogg ◽  
H. Pattyn ◽  
G. Langouche ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ion Beam ◽  
Hexagonal Structure ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Good Crystalline Quality ◽  
Ion Beam Synthesis ◽  
Thermal Stability Of

ABSTRACTThe Nd-disilicide, which exists only in a tetragonal or an orthorhombic structure, cannot be grown epitaxially on a Si(111) substrate. However, by adding Y and using channeled ion beam synthesis, hexagonal Nd0.32Y0.68Si1.7 epilayers with lattice constant of aepi = 0.3915 nm and cepi = 0.4152 nm and with good crystalline quality (χmin of Nd and Y is 3.5% and 4.3 % respectively) are formed in a Si(111) substrate. This shows that the addition of Y to the Nd-Si system forces the latter into a hexagonal structure. The epilayer is stable up to 950 °C; annealing at 1000 °C results in partial transformation into other phases. The formation, the structure and the thermal stability of this ternary silicide have been studied using Rutherford backscattering/channeling, x-ray diffraction and transmission electron microscopy.

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