scholarly journals INFLUENCE OF SOME PARAMETERS IN THE RESULTS OF THERMAL ANALYSIS OF POLYVINYL ALCOHOL

2019 ◽  
Vol 16 (31) ◽  
pp. 235-241
Author(s):  
Mariana Fornazier BORGES
Keyword(s):  
Thermal Analysis ◽  
Polyvinyl Alcohol ◽  
Heating Rate ◽  
Synthetic Polymer ◽  
Qualitative And Quantitative ◽  
Physical Form ◽  
Series Of Experiments ◽  
Rate Type ◽  
Tga And Dsc ◽  
Dsc Curves

The present work seeks to demonstrate through a series of experiments such as the parameters heating rate, type of stand and physical form of the sample, can influence the qualitative and quantitative aspects of the results of the thermal analyzes of TGA and DSC. To do this, polyvinyl alcohol, a synthetic polymer was used as a model and its thermal behavior was discussed by the results obtained by the thermogravimetric (TGA) and DSC curves, showing the effect of the alteration of each parameter, such as the displacement at the temperature at which the thermal events occur in the TGA curves, related to the alteration of the physical form of the sample; the intensification of the DSC peaks due to the increase of the heating rate, the change in the heat flow by changing the stand and masking some events such as the glass transition temperature.

Synthesis of Ultra-Fine ZrB2 Powder by Borothermal Reaction under High Heating Rate

2009 ◽  
Vol 66 ◽  
pp. 77-80 ◽  
Author(s):  
Ge Sun ◽  
Hao Wang ◽  
Wei Min Wang ◽  
Yu Cheng Wang ◽  
Zheng Yi Fu
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Heating Rate ◽  
Zirconium Oxychloride ◽  
Reduction Reaction ◽  
Average Crystalline Size ◽  
High Heating Rate ◽  
Heat Treated ◽  
High Heating ◽  
Borothermal Reduction

Ultra-fine zirconium diboride (ZrB2) powders have been synthesized by borothermal reduction reaction, using zirconium oxychloride (ZrOCl2•8H2O) as the precursors of zirconia. The thermodynamic variation in the amorphous ZrO2-B system was studied by thermogravimetric and differential thermal analysis (TG-DTA). The precursors containing amorphous ZrO2 and B were heat-treated under a high heating rate. It is shown that the borothermal reaction can be completed at a relatively low temperature (~950 °C) and short duration (~5 min) under a heating rate of 200 °C/min. The synthesized powders have an average crystalline size of 300 nm with oxygen content less than 2.62 wt%.

High heating rate thermal analysis

1976 ◽  
Vol 14 (1-2) ◽  
pp. 169-181 ◽  
Author(s):  
A.J. Beardell ◽  
J. Staley ◽  
C. Campbell
Keyword(s):  
Thermal Analysis ◽  
Heating Rate ◽  
High Heating Rate ◽  
High Heating

Identification of Elastomers in Tire Sections by Total Thermal Analysis. III. White Sidewall Compounds of Neoprene Rubber Blends

1975 ◽  
Vol 48 (4) ◽  
pp. 640-652 ◽  
Author(s):  
A. K. Sircar ◽  
T. G. Lamond
Keyword(s):  
Thermal Analysis ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Exothermic Reaction ◽  
Crosslinking Reaction ◽  
Rubber Blends ◽  
Tg And Dtg ◽  
Dsc Curves ◽  
Residual Weight

Abstract DSC curves of sulfur-cured CR differ from peroxide-cured vulcanizates in the shape of the exotherm and the peak temperatures. The exothermic reaction, attributed to dehydrochlorination and subsequent crosslinking, is accelerated by sulfur. TG and DTG curves support this contention. In blends with NR, BR, or SBR, the second polymer intervenes in the crosslinking reaction, resulting in a lower residual weight for the CR network. White sidewall compounds of NR/CR or NR/CR/CSM can be identified by their DSC peaks in nitrogen, glass transition temperature, and DTG peaks. DSC and thermogravimetric curves supplement each other in the identification of these elastomers.

scholarly journals Thermal Analysis On The Kinetics Of Magnesium-Aluminum Layered Double Hydroxides In Different Heating Rates

2015 ◽  
Vol 60 (2) ◽  
pp. 1357-1359 ◽  
Author(s):  
Y. Hongbo ◽  
C. Meiling ◽  
W. Xu ◽  
G. Hong
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Layered Double Hydroxides ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Exponential Factor ◽  
Thermal Kinetic Parameters ◽  
Double Hydroxides ◽  
Kinetics Of ◽  
Dsc Curves

Abstract The thermal decomposition of magnesium-aluminum layered double hydroxides (LDHs) was investigated by thermogravimetry analysis and differential scanning calorimetry (DSC) methods in argon environment. The influence of heating rates (including 2.5, 5, 10, 15 and 20K/min) on the thermal behavior of LDHs was revealed. By the methods of Kissinger and Flynn-Wall-Ozawa, the thermal kinetic parameters of activation energy and pre-exponential factor for the exothermic processes under non-isothermal conditions were calculated using the analysis of corresponding DSC curves.

scholarly journals Heating rate effects on thermal analysis measurement ofTgin composite materials

2017 ◽  
Vol 3 (2) ◽  
pp. 43-51 ◽  
Author(s):  
Ana X. H. Yong ◽  
Graham D. Sims ◽  
Samuel J. P. Gnaniah ◽  
Stephen L. Ogin ◽  
Paul A. Smith
Keyword(s):  
Thermal Analysis ◽  
Composite Materials ◽  
Heating Rate ◽  
Analysis Measurement ◽  
Rate Effects

Study of Influence Factors on Medium-Density Fiberboard Thermal Analysis

2015 ◽  
Vol 1095 ◽  
pp. 468-470
Author(s):  
Ling Liu ◽  
Zheng Xing ◽  
Yi Xiang Liu ◽  
Hua Yi
Keyword(s):  
Thermal Analysis ◽  
Heating Rate ◽  
Medium Density Fiberboard ◽  
Influence Factors ◽  
Fire Investigation ◽  
Medium Density ◽  
Thermo Gravimetry ◽  
Main Influence

The main influence factors on thermal analysis of medium-density fiberboard (MDF) was analyzed by thermo-gravimetry (TG) and derivative thermo-gravimetry (DTG) , which are heating rate, atmosphere and sample . Results showed that heating rate affected the thermo-decomposition obviously, while the effect on the residual charcoal was small, The results can provide reference to extinguishment and fire investigation.

Sintering of Commercial Leucite-Based Dental Porcelains

2008 ◽  
Vol 591-593 ◽  
pp. 692-696
Author(s):  
Cátia Fredericci ◽  
H.N. Yoshimura ◽  
André Luiz Molisani ◽  
C.E. Bellinati ◽  
R.Q.E. Alcântara ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Heating Rate ◽  
Effect Of Temperature ◽  
Surface Microstructure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Increasing Temperature ◽  
Fractured Surface ◽  
Scanning Electron

The aim of this work was to study the effect of temperature and heating rate on the densification of two leucite-based dental porcelains: one low-fusion and one high-fusion commercial leucite porcelains (Dentsply-Ceramco). Porcelain powders were characterized by differential thermal analysis (DTA), X-ray diffraction (XRD), particle size distribution, and helium picnometry. Bar samples were sintered from 650 to 1050oC, using heating rate of 55oC and 10oC/min. Sintered samples were characterized in terms of bulk density, measured by the Archimedes method in water, and fractured surface microstructure by scanning electron microscopy (SEM). The results show that densification increases with increasing temperature and the increase in heating rate has no effect on the densification of the porcelains studied.

Synthesis of stoichiometric lead molybdate PbMoO4: An x-ray diffraction, Fourier transform infrared spectroscopy, and differential thermal analysis study

1996 ◽  
Vol 11 (3) ◽  
pp. 703-715 ◽  
Author(s):  
H. C. Zeng
Keyword(s):  
Thermal Analysis ◽  
Fourier Transform ◽  
Differential Thermal Analysis ◽  
Infrared Spectroscopy ◽  
Heating Rate ◽  
Fourier Transform Infrared Spectroscopy ◽  
Fourier Transform Infrared ◽  
Slow Heating ◽  
X Ray Diffraction ◽  
X Ray

The PbO/MoO3 system with 47%: 53%, 53%: 47%, and 50%: 50% molar ratios at various processing temperatures has been studied with x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential thermal analysis (DTA) methods. It is found that in addition to the crystallization of primary PbMoO4 phase, subphases such as Pb2MoO5 and PbMo2O7 are also formed. The remaining PbO and MoO3 are detected at certain stages of the thermal process due to localized powder inhomogeneity. Physical processes, such as sublimation, eutectic melting, solid to liquid, and liquid to vapor transformations are also investigated. In particular, evaporations of excessive PbO or MoO3 in the nonstoichiometric PbO/MoO3 can be correlated to thermal processing parameters. The current study has led to the following three processing guidelines to obtain stoichiometric PbMoO4: (i) for high temperature application, such as the Czochralski melt growth, it is suggested an excessive MoO3 (a few mol %) must be included and a slow heating rate should be employed; (ii) for low temperature synthesis, the stoichiometric PbO–MoO3 can be used, but with a fast heating rate; and (iii) PbO-rich PbO/MoO3 system is not recommended in PbMoO4 synthesis.

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