Some Aspects on Thermal Degradation of Organo-Layer Silicates

2008 ◽  
Author(s):  
Mervat S. Hassan ◽  
Hassan El-Shall ◽  
Chearly Beaty
Keyword(s):  
Aspect Ratio ◽  
Thermal Degradation ◽  
High Aspect Ratio ◽  
Layered Silicates ◽  
X Ray Diffraction ◽  
X Ray ◽  
Naturally Occurring ◽  
Organically Modified ◽  
The Relationship ◽  
Thermal Stability Of

Naturally occurring silicates, like montmorillonite (MMT) have received much attention as reinforcement materials for polymers because of their potentially high aspect ratio and unique intercalation (exfoliation) characteristic. Montmorillonite is of particular interest because it has a layered structure typically about 1nm in thickness and a high aspect ratio ranging from 100 to 1500 that, with proper exfoliation, can lead to platelets with high stiffness and strength dispersed in the polymer matrix. In this paper, we studied the delamination of Egyptian bentonite and Cloisite Na+ (USA) using different onium ions. The organo-clays were characterized by X-ray diffraction (XRD), Differential Scanning Calorimeter (DSC), Derivativethermogravimetry (TGA), Thermogravimetry (TG), and Infrared spectroscopy (IR). Understanding the relationship between molecular structure of the modifying surfactant and the thermal stability of the organically modified layered silicates is critical to its processing and subsequent applications. Therefore, special emphasis is given to the study of the thermal degradation of the modified clays. The results of the thermal degradation of montmorillonite (MMT) and alkyl quaternary ammonium montmorillonite (OMMT) are discussed in this paper.

High Aspect Ratio Hydroxyapatite Nanorods Formed by Polymer Assisted Synthesis

2014 ◽  
Vol 508 ◽  
pp. 52-55
Author(s):  
A. Joseph Nathanael ◽  
R. Yuvakkumar ◽  
Tae Hwan Oh ◽  
Sun Ig Hong
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Morphological Analysis ◽  
Polymer Concentration ◽  
Xrd Analysis ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Length Width ◽  
Size Controlled

High aspect ratio (length/width) of hydroxyapatite (HA) nanorods were prepared by polymer assisted hydrothermal synthesis. The aspect ratio of the nanorods was increased in the presence of polymer in hydrothermal method. Structural analysis was carried out by X-ray diffraction (XRD) analysis to find the purity and the crystal structure of the material. Morphological analysis was carried out by field emission scanning electron microscope (FESEM) to find the morphological variation in the presence of polymer concentration compared to pristine HA. The increased aspect ratio of the HA was visible from the morphological analysis. This shape and size controlled synthesis have an important impact in many field of research.

Fabrication and Testing of High Aspect Ratio Metal Micro-Gas Chromatograph Columns

2004 ◽  
Author(s):  
Abhinav Bhushan ◽  
Dawit Yemane ◽  
Jost Goettert ◽  
Edward B. Overton ◽  
Michael C. Murphy
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Gas Chromatograph ◽  
X Ray ◽  
Tubular Columns ◽  
Sensor Performance ◽  
Head Pressure ◽  
Separation Columns ◽  
The Relationship ◽  
Rectangular Columns

Micro gas chromatograph (GC) separation columns were fabricated and tested. Rectangular columns with high aspect ratio have inherent benefits over traditional tubular columns and can easily be integrated into a GC sensor system for rapid chromatographic analysis. The 2 m long, 50 μm wide, 500 μm tall columns were fabricated out of electroplated nickel through deep X-ray lithography using the LIGA technique. Critical fabrication issues including reproducible fabrication of compact footprint, deep columns and sealing of the metal columns were addressed. Experiments were conducted to establish the relationship between column head pressure and flow rate. Methane samples analyzed using hydrogen as a carrier gas on uncoated columns showed very little dispersion suggesting that there was no internal leakage in the columns. The sensor performance data compares well with other micro GC sensor systems.

Synthesis of Plate-Like SrTiO3 Particles

2010 ◽  
Vol 663-665 ◽  
pp. 1024-1027
Author(s):  
Wei Zhao ◽  
Ruo Cai Pan ◽  
Hao Xue
Keyword(s):  
Aspect Ratio ◽  
Grain Growth ◽  
High Aspect Ratio ◽  
Growth Process ◽  
The Other ◽  
X Ray Diffraction ◽  
Templated Grain Growth ◽  
X Ray ◽  
Micro Scale ◽  
Textured Ceramics

Micro-scale plake-like SrTO3 particles were synthesized by two routes of topochemical conversion. One is by growing on Sr3Ti2O7 (S3T2) core particles in molten salt condition, and the other is from the layer-structured SrBi4Ti4O15 (SBT) precursor in a KCl medium. The effects of the morphology and size of the precursor to platelet SrTiO3 crystals were studied. X-ray diffraction analysis revealed that the crystallographic {010} plane of SBT was converted into the pseudo-cubic {001} plane of SrTiO3. The polycrystalline SrTiO3 particles from BST precursor exhibited a plate-like shape with 10-15μm in length and a high aspect ratio, and were more suitable for preparing textured ceramics by templated grain growth process than the platelets from the S3T2 precursors.

Flammability and Thermal Degradation of PMMA/Graphene Composites

2014 ◽  
Vol 910 ◽  
pp. 31-34
Author(s):  
Zheng Zhou Wang ◽  
Shao Hong Xu ◽  
Li Xin Wu ◽  
Dong Xian Zhuo
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Thermal Degradation ◽  
Cone Calorimeter ◽  
Pure Pmma ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Heat Release Rate ◽  
Thermal Stability Of ◽  
Scanning Electron

Graphene nanoplatelets (GNP) were prepared by ball milling, and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). PMMA/GNP composites were produced by a melt process. The flammability of PMMA/GNP composite was evaluated by the cone calorimeter (Cone) and thermal degradation of the composite by thermogravimetric analyses (TGA). Cone data indicate that the incorporation of 1% GNP leads to a 12% reduction in the peak heat release rate compared to pure PMMA. The TG results show that the addition of small amount of GNP (1%) can improve thermal stability of PMMA.

Combustibility and Thermal Degradation of PS/IFR/Graphene Composites

2014 ◽  
Vol 687-691 ◽  
pp. 4295-4298
Author(s):  
Jian Wei Yang ◽  
Zheng Zhou Wang ◽  
Li Xin Wu ◽  
Dong Xian Zhuo
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Thermal Degradation ◽  
Cone Calorimeter ◽  
Flame Retardants ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Heat Release Rate ◽  
Thermal Stability Of ◽  
Scanning Electron

Graphene nanoplatelets (GNP) were prepared by ball milling, and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). PS/GNP composites were produced by a melt process. The flammability of PS/GNP composite was evaluated by the cone calorimeter (Cone) and thermal degradation of the composite by thermogravimetric analyses (TGA). Cone data indicate that the incorporation of 1% GNP leads to a 28% reduction in the peak heat release rate (PHRR) compared to pure PS. There is an synerhistic effect between intumesent flame retardants and GNP in a decrease in PhRR in PS. The incorporation of small amount of GNP can improve thermal stability of PS.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

scholarly journals Hydrochloric Acid Modification and Lead Removal Studies on Naturally Occurring Zeolites from Nevada, New Mexico, and Arizona

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1238
Author(s):  
Garven M. Huntley ◽  
Rudy L. Luck ◽  
Michael E. Mullins ◽  
Nick K. Newberry
Keyword(s):  
New Mexico ◽  
Surface Area ◽  
Bet Surface Area ◽  
Lead Removal ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Naturally Occurring ◽  
27Al Mas Nmr ◽  
Modified Zeolites

Four naturally occurring zeolites were examined to verify their assignments as chabazites AZLB-Ca and AZLB-Na (Bowie, Arizona) and clinoptilolites NM-Ca (Winston, New Mexico) and NV-Na (Ash Meadows, Nevada). Based on powder X-ray diffraction, NM-Ca was discovered to be mostly quartz with some clinoptilolite residues. Treatment with concentrated HCl (12.1 M) acid resulted in AZLB-Ca and AZLB-Na, the chabazite-like species, becoming amorphous, as confirmed by powder X-ray diffraction. In contrast, NM-Ca and NV-Na, which are clinoptilolite-like species, withstood boiling in concentrated HCl acid. This treatment removes calcium, magnesium, sodium, potassium, aluminum, and iron atoms or ions from the framework while leaving the silicon framework intact as confirmed via X-ray fluorescence and diffraction. SEM images on calcined and HCl treated NV-Na were obtained. BET surface area analysis confirmed an increase in surface area for the two zeolites after treatment, NM-Ca 20.0(1) to 111(4) m2/g and NV-Na 19.0(4) to 158(7) m2/g. 29Si and 27Al MAS NMR were performed on the natural and treated NV-Na zeolite, and the data for the natural NV-Na zeolite suggested a Si:Al ratio of 4.33 similar to that determined by X-Ray fluorescence of 4.55. Removal of lead ions from solution decreased from the native NM-Ca, 0.27(14), NV-Na, 1.50(17) meq/g compared to the modified zeolites, 30 min HCl treated NM-Ca 0.06(9) and NV-Na, 0.41(23) meq/g, and also decreased upon K+ ion pretreatment in the HCl modified zeolites.

scholarly journals Irregular Electrodeposition of Cu-Sn Alloy Coatings in [EMIM]Cl Outside the Glove Box with Large Layer Thickness

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 310
Author(s):  
Lars Lehmann ◽  
Dominik Höhlich ◽  
Thomas Mehner ◽  
Thomas Lampke
Keyword(s):  
Layer Thickness ◽  
Alloy System ◽  
Liquid Solution ◽  
Complexing Agents ◽  
X Ray Diffraction ◽  
X Ray ◽  
Argon Stream ◽  
Ionic Liquid Solution ◽  
The Relationship ◽  
Layer Composition

Thick Cu−Sn alloy layers were produced in an [EMIM]Cl ionic-liquid solution from CuCl2 and SnCl2 in different ratios. All work, including the electrodeposition, took place outside the glovebox with a continuous argon stream over the electrolyte at 95 °C. The layer composition and layer thickness can be adjusted by the variation of the metal-salts content in the electrolyte. A layer with a thickness of up to 15 µm and a copper content of up to ωCu = 0.86 was obtained. The phase composition was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF). Furthermore, it was found that the relationship between the alloy composition and the concentration of the ions in the electrolyte is described as an irregular alloy system as according to Brenner. Brenner described such systems only for aqueous electrolytes containing complexing agents such as cyanide. In this work, it was confirmed that irregular alloy depositions also occur in [EMIM]Cl.

Fabrication of high aspect ratio nanoscale periodic structures by the soft X-ray interference lithography

2017 ◽  
Vol 170 ◽  
pp. 49-53 ◽  
Author(s):  
Jun Zhao ◽  
Yanqing Wu ◽  
Chaofan Xue ◽  
Shumin Yang ◽  
Liansheng Wang ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Periodic Structures ◽  
Interference Lithography ◽  
X Ray
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