Thermal stability of heat-treated flame-synthesized anatase TiO2 nanoparticles

GeS2 is known to be a good chalcogenide glass former with a transmission cutoff at 11 μm and has been studied for fiber optic application in the mid infrared region. The rare earth sulfides, oxysulfides, and oxides (La–Er) form reasonably good and stable glasses when mixed with chalcogenides such as Ga2S3. In this work, glass formation was studied in the GeS2−La2S3 system. Two compositions containing 60 mol % and 92.5 mol % GeS2, respectively, were analyzed, and the effects of composition on the microstructure and thermal stability of these glasses were investigated. Microstructural studies were conducted on the as-prepared and heat-treated glasses using TEM and SEM/EDXA. Glasses rich in GeS2 exhibited primary (6–88 nm) and secondary (3–13 nm) phase separation at the molecular level. Differential thermal analysis performed on these glasses indicated glass transition temperatures (Tg) of 510 °C and 420 °C for the two compositions studied. The glasses were stable and the (Tg) was observed to decrease with increasing contents of GeS2 in these glasses.

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Effects of aluminum sulfate soaking pretreatment on dimensional stability and thermostability of heat-treated wood

European Journal of Wood and Wood Products ◽

10.1007/s00107-020-01616-8 ◽

2020 ◽

Author(s):

Lijie Qu ◽

Zhenyu Wang ◽

Jing Qian ◽

Zhengbin He ◽

Songlin Yi

Keyword(s):

Heat Treatment ◽

Thermal Stability ◽

Thermal Degradation ◽

Structural Changes ◽

Aluminum Sulfate ◽

Treated Wood ◽

Treatment Temperature ◽

Chinese Fir ◽

Heat Treated ◽

Thermal Stability Of

Abstract Acidic aluminum sulfate hydrolysis solutions can be used to catalyze the thermal degradation of wood in a mild temperature environment, and thus reduce the temperature required for heat treatment process. To improve the dimensional and thermal stability of Chinese fir during heat treatment at 120 °C, 140 °C and 160 °C, this study investigated the effects of soaking pretreatment with 5%, 10% and 15% aluminum sulfate on the chemical and structural changes of the heat-treated Chinese fir. The results indicated that the samples treated at 15% aluminum sulfate concentration and 160 °C heat treatment achieved the best dimensional and thermal stability. Chemical analyses by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) indicated that the catalysis of aluminum sulfate resulted in degradation of hemicelluloses during the heat treatment, and an increase in the soaking concentration and heat treatment temperature also affected the thermal degradation of celluloses. The scanning electron microscope (SEM) and mass changes test results proved that the hydrolyzed aluminum flocs mainly adhered to the inner wall of the wood tracheid as spherical precipitates, and when the soaking concentration reached 10% and 15%, a uniform soaking effect could be achieved. The thermogravimetric (TG) analysis revealed the soaking pretreatment effectively improved the thermal stability of the heat-treated wood by physically wrapping and promoting the formation of a carbon layer on the wood surface during heat treatment. Thus, aluminum sulfate soaking pretreatment exerted a great effect on the dimensional and thermal stability of wood, allowing heat treatment to be performed at a lower temperature.

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Study on the thermal stability of Ga-doped ZnO thin film: A transparent conductive layer for dye-sensitized TiO2 nanoparticles based solar cells

Materials Science in Semiconductor Processing ◽

10.1016/j.mssp.2014.05.016 ◽

2014 ◽

Vol 26 ◽

pp. 276-281 ◽

Cited By ~ 10

Author(s):

Li Gong ◽

Yunzhen Liu ◽

Xiuquan Gu ◽

Jianguo Lu ◽

Jie Zhang ◽

...

Keyword(s):

Thin Film ◽

Thermal Stability ◽

Solar Cells ◽

Tio2 Nanoparticles ◽

Zno Thin Film ◽

Conductive Layer ◽

Dye Sensitized ◽

Doped Zno ◽

Thermal Stability Of ◽

Transparent Conductive Layer

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Chemical and Thermal Stability of Multiple Ions Doped Non-Stoichiometric Nanoapatite Heat-Treated in CO2 and Air Atmospheres

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.925.77 ◽

2014 ◽

Vol 925 ◽

pp. 77-81

Author(s):

K. Jamuna Thevi ◽

Mohammed Rafiq Abdul Kadir ◽

Hendra Hermawan

Keyword(s):

Thermal Stability ◽

Nanocrystalline Phase ◽

Secondary Phases ◽

Wet Precipitation ◽

Carbonate Ions ◽

Precipitation Technique ◽

Heat Treated ◽

Phase Pure ◽

20 Nm ◽

Thermal Stability Of

Nanostructured apatite has been widely used as a bone substitute material due to its close resemblance to human bone mineral. To further mimic biological apatites, multiple ions doped non-stoichiometric nanoapatite has been studied. A nanosized apatite (NAp-2) containing Mg (1.09 wt%), Na (0.15 wt%), K (0.008 wt%) and CO32- (5.18 wt%) was synthesized by a wet precipitation technique. The presence of these ions in NAp-2 was detected using ICP. Broad diffraction peaks of XRD results indicated the presence of nanocrystalline phase pure NAp-2. The primary particle size of the resulted powder was ~ 20 nm, typical of bone crystal size, estimated using Scherrers equation. Based on CHN results, the NAp-2 powders showed a total loss of 51 and 78% of carbonate ions when heat-treated at 900°C in both CO2 and air atmospheres, respectively. This indicates that the heat-treatment in CO2 flux has reduced the carbonate ions lost from the NAp-2. A highly crystalline HA phase was formed in the ionic doped NAp-2 without secondary phases, indicating a thermal stability of this powder at 900°C in CO2 and air atmospheres. Thus, this study demonstrated that a phase pure multiple ions doped nanoapatite was synthesized using a wet precipitation technique.

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Thermal Degradation Study of Functionalized MWNT Reinforced Segmented Polyurethane Membrane

Journal of Elastomers & Plastics ◽

10.1177/0095244306064237 ◽

2006 ◽

Vol 38 (3) ◽

pp. 261-271 ◽

Cited By ~ 14

Author(s):

S. Mondal ◽

J. L. Hu

Keyword(s):

Thermal Stability ◽

Thermal Degradation ◽

Nitrogen Atmosphere ◽

Segmented Polyurethane ◽

Degradation Study ◽

Heat Treated ◽

Different Temperatures ◽

Increasing Temperature ◽

Thermal Stability Of ◽

Mwnt Content

The thermal degradation of polytetramethylene glycol (PTMG, Mn 1/42900) based polyurethane (PU), along with four different weight contents (such as 0.25, 0.50, 1.0, and 2.5 wt%) of functionalized multiwalled nanotube (MWNT) reinforced PUs are studied in air as well as in nitrogen atmosphere. The degradation results are reported in 10 and 50% weight loss and derivative of thermogravimetry (DTG). As expected, PUs are thermally more stable in nitrogen than in air. However, the influence of MWNT content on thermal stability is unclear. At 0.25 and 0.50 wt% of MWNT content, thermal stability declined and a further increase of MWNT improved the thermal stability of PU. Fourier-transform infrared (FTIR) analysis is also performed for untreated and heat treated films in order to understand the degradation at different temperatures. Free C1/4O stretching neck dimension increases with increasing temperature which signifies breaking of H-bonding detected by FTIR measure ments.

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