scholarly journals Thermal stabilities of aromatic polymers and polyimides in nitrogen flow determined by thermogravimetric analysis.

1990 ◽  
Vol 47 (3) ◽  
pp. 207-214 ◽  
Author(s):  
Rikio YOKOTA ◽  
Takahiro SAKINO ◽  
Itaru MITA
Keyword(s):  
Thermogravimetric Analysis ◽  
Nitrogen Flow ◽  
Thermal Stabilities ◽  
Aromatic Polymers

scholarly journals Thermal degradation behaviour of some polydithiooxamide metal complexes

2006 ◽  
Vol 31 (1) ◽  
pp. 45-52 ◽  
Author(s):  
H. Al-Maydama ◽  
A. El-Shekeil ◽  
M. A. Khalid ◽  
A. Al-Karbouly
Keyword(s):  
Thermal Decomposition ◽  
Thermogravimetric Analysis ◽  
Integral Method ◽  
Valence Shell ◽  
Degradation Behaviour ◽  
Thermal Stabilities ◽  
Electron Pairs ◽  
Thermal Decomposition Behavior ◽  
The Difference ◽  
Decomposition Behavior

The thermal decomposition behavior of the Fe(II), Co(II), Ni(II) and Zn(II) complexes of polydithiooxamide has been investigated by thermogravimetric analysis (TGA) at a heating rate of 20°C min-1 under nitrogen. The Coats-Redfern integral method is used to evaluate the kinetic parameters for the successive steps in the decomposition sequence observed in the TGA curves. The processes of thermal decomposition taking place in the four complexes are studied comparatively as the TGA curves indicate the difference in the thermal decomposition behavior of these complexes. The thermal stabilities of these complexes are discussed in terms of repulsion among electron pairs in the valence shell of the central ion and electronegativity effects.

TG-FTIR Analysis of Sewage Sludge: Influence of Moisture and Atmosphere

2015 ◽  
Vol 768 ◽  
pp. 532-541
Author(s):  
Qian Jin Dai ◽  
Xu Guang Jiang ◽  
Yu Qi Jin ◽  
Fei Wang ◽  
Yong Chi ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Thermogravimetric Analysis ◽  
Sewage Sludge ◽  
Air Flow ◽  
Infrared Analysis ◽  
Gas Evolution ◽  
Ftir Analysis ◽  
Nitrogen Flow ◽  
Char Combustion ◽  
Two Peaks

Thermogravimetric analysis (TGA), coupled with Fourier transform infrared analysis (TG-FTIR) of sewage sludge was carried out to investigate the influence of moisture and oxygen on gas evolution during pyrolysis of sewage sludge. Wet sewage sludge with moisture of 86.47(wt. %) was collected from Shanghai, China. Wet sewage sludge and air dried sewage sludge were used in TG-FTIR analysis, while combustion (air flow) and pyrolysis (nitrogen flow) were separately introduced to achieve comparison. In condition of dry sewage sludge pyrolysis, there were two peaks representing release of separately moisture and volatile. Weight lost 85% in the temperature range of 25-600 °C while the main volatile matters were released before 600 °C. When air flow was introduced, a third peak of char combustion occurred. Wet sewage sludge made no much difference, except for the relatively outstanding peak of moisture release. Temperature regions for each stage were the same for wet and dry sewage sludge from TG curve. However, from the FTIR analysis, ammonia has two peaks between 50 and 450 °C in pyrolysis while ammonia has only one peak between 50 and 300°C.

scholarly journals Thermoanalytical Study and Kinetics of New 8-Hydroxyquinoline 5-sulphonic Acid-Oxamide-Formaldehyde Terpolymer Resins

2009 ◽  
Vol 6 (s1) ◽  
pp. S171-S182
Author(s):  
Rajesh N. Singru ◽  
Anil B. Zade ◽  
Wasudeo B. Gurnule
Keyword(s):  
Activation Energy ◽  
Thermogravimetric Analysis ◽  
Thermal Activation ◽  
Acid Catalyst ◽  
Frequency Factor ◽  
Entropy Change ◽  
Thermal Activation Energy ◽  
Sulphonic Acid ◽  
Thermal Stabilities ◽  
Continuous Increase

The terpolymer resins (8-HQ5-SAOF) have been synthesized by the condensation of 8-hydroxyquinoline 5-sulphonic acid (8-HQ5-SA) and oxamide (O) with formaldehyde (F) in the presence of acid catalyst and using varied molar proportion of the reacting monomers. The synthesized terpolymer resins have been characterized by different physico-chemical techniques. Thermogravimetric analysis of all terpolymer resins in present study have been carried out by non-isothermal thermogravimetric analysis technique in which sample is subjected to condition of continuous increase in temperature at linear rate. Thermal study of the resins was carried out to determine their mode of decomposition and relative thermal stabilities. Thermal decomposition curves were studied carefully with minute details. The Freeman-Carroll and Sharp-Wentworth methods have been used in the present investigation to calculate thermal activation energy and different kinetic parameter of the terpolymer resins. Thermal activation energy (Ea) calculated with above two mentioned methods are in close agreement. The advantage of Freeman-Carroll method is to calculate both the order of reaction (n) and energy of activation in one single stage by keeping heating rate constant. By using data of thermogravimetric analysis, various thermodynamic parameters like frequency factor (Z), entropy change (Δ S), free energy change (Δ F) and apparent entropy (S*) have been determined using Freeman-Carroll method.

Tetrathia Macrocycle-bridged Dimeric with Hexakis (alkylthio) Substituents and Network Polymer Phthalocyanines

1997 ◽  
Vol 01 (03) ◽  
pp. 227-237 ◽  
Author(s):  
A. G. GÜREK ◽  
Ö. BEKARO ĞLU
Keyword(s):  
Electrical Conductivity ◽  
Thermogravimetric Analysis ◽  
Chemical Doping ◽  
Organic Base ◽  
Network Polymer ◽  
Thermal Stabilities ◽  
H Nmr ◽  
Elemental Analyses ◽  
New Compounds ◽  
C Nmr

1,4,7,10-Tetrathia (12-crown-4)-bridged new polymeric phthalocyanines 9 and 10 have been synthesized by the reaction of tetracyanodibenzo[1,4,7,10-tetrathia (12-crown-4)] in the presence of a strong organic base or Zn ( OAc )2 respectively. Furthermore, 1,4,7,10-tetrathia (12-crown-4)-linked peripherally octa-substituted dimeric phthalocyanine 12, which contains a combination of hexakis(alkylthia) side chains was synthesized by the reaction of subphthalocyanine 11 with the iminoisoindoline derivative 8. The new compounds have been characterized by elemental analyses, IR, UV/vis, mass, 1 H NMR and 13 C NMR spectroscopy. The thermal stabilities of the compounds were determined by thermogravimetric analysis. The electrical conductivity of the polymeric, 9 and 10, and dimeric phthalocyanines, 12 and 13, are in the semiconductor range; chemical doping with NOBF 4 increases the d.c. conductivity of 10 by a factor of four.

scholarly journals Solvate Formation of Bis(demethoxy)curcumin: Screening and Characterization

Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 407 ◽  
Author(s):  
Lina Yuan ◽  
Heike Lorenz
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Mass Loss ◽  
Storage Conditions ◽  
Stoichiometric Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
X Ray ◽  
Ambient Storage

Solvate formation of bis(demethoxy)curcumin (BDMC) was screened. Six solvates were obtained out of the nineteen solvents investigated. In the present work, three solvates, i.e., BDMC-tetrahydrofuran (THF), BDMC-1,4-dioxane (DIO) and BDMC-dimethyl sulfoxide (DMSO), were thoroughly studied. Their desolvation processes were characterized by temperature-resolved powder X-ray diffraction (TR-PXRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and hot-stage microscopy (HSM). TR-PXRD shows that all the solvates desolvate as the mother BDMC form and no new polymorph could be obtained. The stoichiometric ratio of solvates was calculated via the mass loss of solvents determined by TGA. The thermal stabilities of the solvates were obtained from DSC data and followed the order: BDMC-DMSO > -THF > -DIO. Moreover, stability performances at ambient storage conditions recorded by PXRD show that BDMC-DMSO was stable over three months.

A New Kind of Silica Microspheres Used as Filler for PDMS Composite

2012 ◽  
Vol 534 ◽  
pp. 184-187
Author(s):  
Wen Juan Gu ◽  
Bang Gui He ◽  
Yang Li
Keyword(s):  
Mechanical Properties ◽  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Tensile Testing ◽  
Sol Gel ◽  
Hybrid Membrane ◽  
Experimental Results ◽  
Silica Microspheres ◽  
Thermal Stabilities ◽  
Gel Method

A new kind of silica microspheres were first synthesized with dodecyltrimethoxysilane (WD10) and tetraethoxysilane (TEOS) by sol-gel method. And hybrid membrane was prepared by incorporating the as prepared filler into polydimethylsiloxane (PDMS). Thermal degradation and mechanical properties of these composites membranes were studied by means of thermogravimetric analysis and tensile testing. The experimental results showed that both mechanical properties and thermal stabilities of these composites were significantly improved by using the as-synthesized filler.

Improvement of Thermal and Ablative Properties of Phenolic Resin by SiC and MMT

2016 ◽  
Vol 707 ◽  
pp. 8-12
Author(s):  
Keeratikarn Kuttiwong ◽  
Jantrawan Pumchusak
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Thermogravimetric Analysis ◽  
Phenolic Resin ◽  
Testing Machine ◽  
Hot Compression ◽  
Thermal Stabilities ◽  
Universal Testing Machine ◽  
Universal Testing

In this work, the improvement of thermal and ablative properties of the phenolic resin by the addition of silicon carbide (SiC) and montmorillonite (MMT) were studied. The phenolic composites were fabricated by hot compression. The thermal stabilities, mechanical properties and ablative properties of the neat phenolic resin and the SiC/MMT phenolic composites were examined using a Lloyd universal testing machine, thermogravimetric analysis (TGA) and ablation tests (an oxyacetylene torch), respectively. Mass ablation rates were measured after flame exposure. The results showed that SiC/MMT provided the higher thermal stabilities and lower ablation rates to the phenolic resin.

Synthesis, Crystal Structures, and Nonlinear Optic and Thermal Properties of Two Diiodocarbazole Derivatives

2017 ◽  
Vol 41 (2) ◽  
pp. 79-81 ◽  
Author(s):  
Gui-Mei Tang ◽  
Rui-Hai Chi ◽  
Wen-Zhu Wan ◽  
Yong-Tao Wang ◽  
Yue-Zhi Cui ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Thermogravimetric Analysis ◽  
Second Harmonic Generation ◽  
Crystal Structures ◽  
Nonlinear Optic ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Decomposition Temperature ◽  
Thermal Stabilities ◽  
Space Group

Two 3,6-diiodocarbazole derivatives were prepared from the iodination of the corresponding phenylcarbazole. 3,6-Diiodo-9-phenylcarbazole crystallises in the chiral space group P21 and shows good second-harmonic generation effects. Thermogravimetric analysis of the two compounds shows high thermal stabilities, in which the decomposition temperature for 1 and 2 are 273 and 308 °C, respectively.

scholarly journals Thermal behavior and thermodynamic parameters of some complexes of biologically active nucleic acid constituents

2021 ◽  
Vol 12 (2) ◽  
pp. 078-108
Author(s):  
M. S. Masoud ◽  
M. Sh. Ramadan ◽  
A. M. Sweyllam ◽  
A. M. Ramadan ◽  
M. H. Al-Saify
Keyword(s):  
Differential Scanning Calorimetry ◽  
Nucleic Acid ◽  
Thermogravimetric Analysis ◽  
Thermal Behavior ◽  
Thermodynamic Parameters ◽  
Biologically Active ◽  
Molecular Configuration ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Mechanism Of Decomposition

The thermal behavior of some complexes derived from biologically nucleic acid constituents has been studied applying differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. Thermodynamic parameters, decompositions and thermal stabilities are calculated and explained. All the complexes gave exothermic peaks with -ve signs for change of entropy values, ΔS which indicate that the activated transition states are more ordered, i.e. in a less random molecular configuration than the reacting complexes. TGA gives the mechanism of decomposition.

Two one-dimensional linear zinc(II) polymers:catena-poly[[[2,6-bis(1H-benzimidazol-2-yl-κN3)pyridine]zinc(II)]-μ-pyridine-2,4-dicarboxylato-κ2O2:O4] andcatena-poly[[[2,6-bis(1H-benzimidazol-2-yl-κN3)pyridine]zinc(II)]-μ-pyridine-2,5-dicarboxylato-κ2O2:O5]

2013 ◽  
Vol 69 (7) ◽  
pp. 750-753
Author(s):  
Jing Xiang
Keyword(s):  
Solid State ◽  
Thermogravimetric Analysis ◽  
Dicarboxylic Acid ◽  
Room Temperature ◽  
Photoluminescence Properties ◽  
Thermal Stabilities ◽  
One Dimensional ◽  
Title One

The solvothermal reactions of 2,6-bis(1H-benzimidazol-2-yl)pyridine (H2bpp) and hydrated ZnCl2in the presence of pyridine-2,4-dicarboxylic acid (2,4-pdcH2) or pyridine-2,5-dicarboxylic acid (2,5-pdcH2) afforded the title one-dimensional linear compounds, [Zn(C7H3NO4)(C19H13N5)]nor [Zn(2,4-pdc)(H2bpp)]n, (I), and [Zn(C7H3NO4)(C19H13N5)]nor [Zn(2,5-pdc)(H2bpp)]n, (II), respectively. The ZnIIcations in these compounds have closely comparable geometries and both are octahedrally coordinated by N4O2donor sets. The thermal stabilities have been investigated by thermogravimetric analysis (TGA) on the crystalline samples and their solid-state photoluminescence properties have been investigated at room temperature.

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