TG-DTA Analysis Research Articles

Synthesis and Biological Activity of Eugenol-Copper Complex

Metal chelate of bioactive metal ion Cu(II) with eugenol was chelated for improving the ligand's efficiency and the complex synthesized was characterized through FT-IR, TG-DTA, AAS and elemental analysis. The composition of eugenol-copper in complex was found to be 1:1 through Job's method. In vitro antimicrobial test of eugenol, eugenol-copper complex and CuSO4.5H2O was conducted against phytopathogenic fungi Pyricularia grisea Sacc., Helminthosporium oryzae Breda de Haan and Curvularia lunata (Wakker) Boedijin through conidial germination test that revealed enhanced fungi-toxicity of the complex compared to either eugenol or CuSO4.5H2O alone especially against the former pathogen.

Fabrication and Characterization of Fe doped TiO2 particles by combination the sol-gel and hydrothermal processes

Iron doped TiO2 nanoparticles were prepared under the high temperature and pressure conditions by mixture of metal nitrates solution and TiO2 sol. Fe doped TiO2 particles were reaction at the temperature range of 170°C–200°C for 6 h. The microstructure and phase of synthesized particles were studied by SEM(FE-SEM), TEM and XRD. Thermal properties of the synthesized particles were investigated by TG-DTA analysis. Also, Specific Surface Area of synthesized particles were studied by BET analysis. X-ray diffraction pattern shows that the synthesized particles shows the coexistence of anatase and rutile reaction at the temperature range of 170°C to 200°C for 6 h. The amount of rutile phase on the synthesized particles increased with decreasing Ag concentration in solution because the less a content of the transposition metal, the easier to phase transition in the same temperature condition. The average size and distribution of the synthesized particles was about 10nm and narrow, respectively. The average size of the synthesized particles increased as reaction temperature increased. Also, BET surface areas of synthesized particles by a hydrothermal process were found to be larger than that of pure TiO2 which is synthesized by a sol-gel process.

Synthesis and electromagnetic properties of BaFe11.92(LaNd)0.04O19/titanium dioxide composites

Doped BaFe11.92(LaNd)0.04O19/titanium dioxide composites have been prepared by the gel-precursor self-propagating combustion process. The characterization of the composites are performed by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), Differential thermal analysis-thermo gravimetry (DTA–TG), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and network analyzer. Both XRD and FT-IR indicate that the doped BaFe11.92(LaNd)0.04O19/titanium dioxide composites are successfully synthesized and there are some interactions between BaFe11.92(LaNd)0.04O19 and titanium dioxide. DTA–TG analysis of BaFe11.92(LaNd)0.04O19/titanium dioxide composites shows that the composite gel decomposition process mainly includes two stages: the first stage is the crystallized water and the residual moisture evaporation; the second stage is the nitrate and citric acid decomposition reaction. SEM demonstrates that the doped BaFe11.92(LaNd)0.04O19/titanium dioxide solid solution has formed. The magnetic parameters indicate that the electromagnetic properties of the composites could be well adjusted by the mass ratio of BaFe11.92(LaNd)0.04O19 and titanium dioxide. When the mass ratio of BaFe11.92(LaNd)0.04O19 and titanium dioxide is 4:5, the composites have the best magnetic loss. The composites with the mass ratio 6:5 of BaFe11.92(LaNd)0.04O19 and titanium dioxide. BaFe11.92(LaNd)0.04O19 and titanium dioxide possess good dielectric loss. The introduction of titanium dioxide enhances the dielectric loss and widens the frequency bands. The composites will be promising microwave absorption materials with wide frequency band.

Synthesis, crystal structure and spectroscopic properties of a supramolecular zinc(II) complex with N2O2 coordination sphere

A new hexa-coordinated zinc(II) complex, namely [ZnL(H2O)2]n, with N2O2 coordination sphere (H2L=4,4′-dibromo-6,6′-dichloro-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol) has been synthesized and structurally characterized by elemental analyses, IR, UV–vis spectra and TG-DTA analyses, etc. Crystallographic data are monoclinic, space group P21/c, a=24.634(2)Å, b=10.144(1)Å, c=7.9351(6)Å, β=91.371(2)°, V=1982.4(3)Å3, Dc=2.099g/cm3, Z=4. The zinc(II) complex exhibits a slightly distorted octahedral geometry with halogen-substituted Salen-type bisoxime forming the basal N2O2 coordination sphere and two oxygen atoms from two coordinated water molecules in the axial position. The hydrogen-bonding and π–π stacking interactions have stabilized the zinc(II) complex molecules to form a self-assembling infinite dual metal–water chain-like structure with the nearest Zn⋯Zn distance of 4.954(4)Å.

Thermal, fluorescence, and electrochemical characteristics of novel poly(urethane-imide)s

In this study, the novel thermally stable poly(urethane-imide)s (PUIs) were synthesized. The structures of the obtained polymers were confirmed by FT-IR and NMR techniques. The molecular weight distribution parameters of the synthesized PUIs were determined by the size exclusion chromatography (SEC). The synthesized PUIs were also characterized by solubility tests, solution viscosity, TG-DTA, and DSC analyses. Cyclic voltammetry measurements were carried out, and HOMO–LUMO energy levels and electrochemical band gaps () were calculated from their absorption edges. Additionally, optical band gaps (Eg) were determined by using UV–vis spectra of the materials. Fluorescence measurements were carried out in various concentrated DMSO solutions to determine the optimum concentrations to obtain the maximal PL intensities. Also, morphological characterizations were made by scanning electron microscopy technique.

Effect of progressive Co loading on commercial Co–Mo/Al2O3 catalyst for natural gas decomposition to COx-free hydrogen production and carbon nanotubes

Successive cobalt increments from 3.1% up to 40.0% in a commercial hydrotreating catalyst containing originally 3.1%Co and 10.5%Mo on γ-Al2O3 was investigated at a reaction temperature of 700°C and atmospheric pressure for the catalytic decomposition of natural gas to CO/CO2 free hydrogen and carbon nanomaterials. The fresh and used catalysts were characterized by XRD, BET, TEM and TG-DTA analysis. The catalytic performance data showed that the increase of cobalt concentration improved the catalytic dissociation activity and longevity toward hydrogen production. All surface properties declined with successive addition of cobalt in the catalysts. XRD results showed that the crystallinity was remarkably enhanced and Co3O4 phases predominate upon addition of the cobalt precursor. The catalytic activity was found to be primarily dependent on the extent and degree of isolation of Co3O4 phases on the catalyst surface which reflects that the current reaction is a metal catalyzed one. The influence of metal content on the total carbon yield and the degree of graphitization of the resulting CNTs was investigated by TGA, XRD, Raman spectroscopy and TEM analysis.

Synthesis, crystal growth, structural, thermal, optical and mechanical properties of solution grown 4-methylpyridinium 4-hydroxybenzoate single crystal

Organic nonlinear optical material, 4-methylpyridinium 4-hydroxybenzoate (4MPHB) was synthesized and single crystal was grown by slow evaporation solution growth method. Single crystal and powder X-ray diffraction analyses confirm the structure and crystalline perfection of 4MPHB crystal. Infrared, Raman and NMR spectroscopy techniques were used to elucidate the functional groups present in the compound. TG-DTA analysis was carried out in nitrogen atmosphere to study the decomposition stages, endothermic and exothermic reactions. UV–visible and Photoluminescence spectra were recorded for the grown crystal to estimate the transmittance and band gap energy respectively. Linear refractive index, birefringence, and SHG efficiency of the grown crystal were studied. Laser induced surface damage threshold and mechanical properties of grown crystal were studied to assess the suitability of the grown crystals for device applications.

The Effect of Cation Substitution on Chemical Stability of Ba0.5Sr0.5Co0.8Fe0.2O3-δ -Based Mixed Conductors

Cubic perovskite Ba0.5Sr0.5Co0. 8Fe0.1R0.1O3–δ (R=Fe, Nb, Mo, Sb) was synthesized, and the chemical stability under high oxygen partial pressure (p(O2)) was studied by using HT-XRD in the temperature range of 773-1373 K. It was found that Ba0.5Sr0.5Co0. 8Fe0.1Sb0.1O3–δ was remarkably stable than Ba0.5Sr0.5Co0. 8Fe0.2O3–δ and Ba0.5Sr0.5Co0. 8Fe0.1Mo0.1O3–δ in high p(O2) condition. The effect of B-site substitution on the CO2-tolerance of Ba0.5Sr0.5Co0. 8Fe0.1R0.1O3–δ was also investigated by TG-DTA analysis at 300-1373 K. It was demonstrated that the chemical stability of Ba0.5Sr0.5Co0. 8Fe0.2O3–δ against CO2 could be significantly improved when Fe were partially substituted by Nb or Sb ions.

Composition and physicochemical properties of Zedo gum exudates from Amygdalus scoparia

Composition and physicochemical properties of three types of Zedo gum exudates from Amygdalus scoparia were investigated. Monosaccharide analysis by GC–MS indicated the occurrence of arabinose and galactose as the main sugars. FTIR spectra showed no differences in functional groups among the samples. Steady shear rheological data and power law parameters revealed that the white gum (W) was the most shear sensitive type and had the highest value of consistency coefficient. The mechanical spectra derived from the strain and frequency sweep measurements indicated a liquid viscoelastic behavior for Zedo gum dispersions. GPC–MALLS revealed that the white sample had the highest apparent average molecular weight (4.74×106Da) and the lowest dispersity (1.045). TG–DTA analysis showed that the character of gum decomposition significantly depended on the gum type and the white sample had the highest thermal stability.

Highly conductive barium zirconate-based carbonate composite electrolytes for intermediate temperature-protonic ceramic fuel cells

Abstract Two-phase composite materials consisting of a BZY matrix phase and a binary eutectic carbonate (Li–0.5Na) 2 CO 3 phase are designed in order to promote the densification and ionic conductivity of BaZr 0.85 Y 0.15 O 3 − δ (BZY) proton conductors at intermediate temperature. In the presence of carbonate phase, a considerable change in microstructure for the densification of BZY electrolytes sintered at 670 °C for 4 h is clearly visible in SEM analysis. This sintering effect is due to the formation of molten phase associated with carbonates at low temperature (495 °C) by TG–DTA analysis. The conductivity of composite electrolytes is significantly higher than that of BZY over the entire temperature and atmosphere range studied by AC impedance and DC four-probe methods. In addition, the change of the carbonate content in the composite electrolyte presents a great influence on the conductivity. The composite containing 25 wt.% (Li–0.5Na) 2 CO 3 shows the highest ionic conductivity of 0.176 S cm −1 at 550 °C and lowest activation energy of 0.127 eV in the temperature range of 500–650 °C.

Rectangular Palladium Nanoparticles (RNPs): Synthesis, Characterization, and Mechanistic Studies

Rectangular palladium nanoparticles have been synthesized by the reduction of PdCl2 with ethylene glycol (EG) in presence of cetyltrimethylammonium bromide (CTAB) and disodiumtartarate in acid media. Here CTAB and disodium tartarate acts as surfactant and directing agent for selective yield of nanocubes and nanobars. The morphology of Pd nanocrystals can be tuned by varying concentration of EG, CTAB, and disodium tartarate. The powders were characterized by XRD, FESEM, and TEM studies. Reaction intermediate was studied by UV-Vis spectra and characterized by TG-DTA analysis. An equilibrium mechanism is proposed where Na+ plays an important role in the formation of Pd nanopowder.

Fullerene Derivatives, Preparation, Identification and Use

This article is focused on oxidation and halogenation of fullerene, identification of the prepared products and their potential application. The Fourier transform infrared (FTIR) spectrometry was used for analysis of oxidized fullerene derivative and material balance and elemental analysis were used to identify the summary composition of the prepared fullerene halogen derivatives. We has conformed yet the radioprotective ability of oxidized fullerene in our recently published work radioprotective properties and toxicity test of C60 fullerene derivative in vivo & in vitro. Since radioprotective properties are associated with the ability to recapture free radicals in the system (formed due to radiolysis of water in the physiological environment), this property is closely connected also with fire-retarder properties, when the fire is also a radical mechanism. We tested thermal properties of polyvinyl alcohol (hereinafter PVA) nanofibers prepared with C60 and its derivatives as nanocomposites. The TG-DTA and TG-DSC analysis were used for this purpose. We have demonstrated experimentally that a retarder on C60oxi basis and C60 halogenderivative has good results in increasing of thermal resistance of PVA-based nanofibers.

CTAB-assisted synthesis of mesoporous CoFe2O4 with high carbon monoxide oxidation activity

Mesoporous CoFe2O4 nanomaterials were successfully synthesized via the cetyltrimethylammonium bromide (CTAB)-assisted method at normal pressure. The structure and morphology of the as-prepared CoFe2O4 samples were characterized by XRD, TG-DTA, FT-IR, TEM and N2-sorption analysis. XRD studies indicated that the as-prepared product was well-crystallized spinel cobalt ferrite. The TEM image showed that the obtained CoFe2O4 sample consisted of nanoparticles with the size about 15nm. N2-sorption analysis indicated that the mesoporous CoFe2O4 possesses a wormhole-like mesoporous structure with a narrow pore size distribution and high surface area (94.3m2/g). The catalytic property of the as-prepared CoFe2O4 for low-temperature CO oxidation was evaluated by using a microreactor-GC system, and the result shows that it is very active for CO total oxidation at 140°C.

MgAl2O4 nanopowder synthesis by microwave assisted high energy ball-milling

Abstract This paper reports the development of a new process for the synthesis of spinel nano powder via microwave assisted high energy ball milling of a powder mixture containing Al(OH)3 and Mg(OH)2. X-ray diffraction (XRD), Simultaneous thermal analysis (STA), FTIR spectrometer, BET and scanning electron microscopy (SEM) techniques were utilized to characterize the as-milled and annealed samples. X-ray diffraction results provide evidence for the formation of a completely amorphous phase after milling for 8 h. It is found that highly ordered MgAl2O4 spinel can be obtained by calcination the as-milled powder over 800 °C. Also, SEM observations of synthesized powders showed that the particle size of powders lies in the nano meter range compared with the BET results (about 28–149 nm). The DTA–TG analyses were carried out to investigate the effect of microwave heating on the synthesis temperature compared to the conventional heat treatment by conventional furnace. Synthesis of powders with different heating methods showed that microwave heating reduces the synthesis temperature by about 200 °C.

Comparison of aqueous- and non-aqueous-based tape casting for preparing YAG transparent ceramics

Transparent YAG ceramics were prepared by the aqueous and non-aqueous based tape casting methods. The rheological property of the slurries was analyzed by the viscosity–shear rate curves. The thermal character was detected by the TG–DTA analysis. The microstructures of the tapes and ceramics were compared. The influence of density of the tape on the ceramics were discussed. The in-line transmittance curves were compared to analyze the optical quality of obtained samples. Results indicate that the methods mentioned above can achieve transparent YAG ceramics with multilayer structure. The transmittance of the sample prepared by the aqueous tape casting is above 81% at 400 nm and the sample fabricated by the non-aqueous tape casting possesses higher optical properties. The transmittance is higher than 82% at 400 nm and reaches 84% at 1064 nm.

Biosynthesis of silver nanoparticles using Tithonia diversifolia leaf extract and their antimicrobial activity

A green approach for the synthesis of silver nanoparticles (AgNPs) using aqueous leaf extract of Tithonia diversifolia under ambient conditions was studied. The effect of pH on biosynthesis of AgNPs was investigated by UV–vis spectrophotometer. TEM images showed that the diameter of stable AgNPs was approximately 25nm. TG-DTA analysis revealed that content of biomolecules surrounding silver was about 24.2%. Moreover the antimicrobial activity of synthesized AgNPs against Pseudomonas aeruginosa, Microbacterium foliorum, Bacillus subtilis, and Rhodococcus equi was screened.

Synthesis, Characterization, Thermodynamics Stability Constant, and Relaxation Properties of Neutral Gadolinium(III) Complex With Derivatives From Diethylene Triamine Pentaacetic Acid and m-hydroxybenzoyl Hydrazine

A novel ligand, diethylenetriamine-N,N″-bis(acetyl-m-hydroxybenzoyl hydrazine)-N, N′, N″-triacetic acid (H3L), was synthesized and characterized on the basis of elemental analysis, molar conductivities, 1H NMR, FAB-MS, TG-DTA analysis, and IR methods. Its complex of Gd(III) holding promise of magnetic resonance imaging(MRI) was synthesized, and relaxivity of GdL and Gd(DTPA)2– used as compare were determined in water solution, respectively. The relaxivity of GdL (R1 = 6.02 L·mmol–1·s–1) was larger than that of Gd(DTPA)2–(R1 = 4.34L·mmol–1·s–1). The relaxivity of GdL had also been investigated in human serum albumin (HSA) solution, the relaxivity of GdL was enhanced from 6.02 L·mmol–1·s–1 in water solution to 7.10 L·mmol–1·s–1 in HSA solution. In addition, thermodynamics stability constant of GdL complex was determined. The results showed that GdL is a prospective MRI contrast agent, although the thermodynamic stability constant of GdL complex(K GdL = 1019.92) was a little less than that of Gd(DTPA)2–(KGd-DTPA = 1020.73).

Various nickel doping in commercial Ni–Mo/Al2O3 as catalysts for natural gas decomposition to COx-free hydrogen production

Non-oxidative decomposition of natural gas to COx-free hydrogen production over commercial nickel-molybdate hydrotreating catalysts with different Ni loading from 5 to 40wt% were studied at 700 °C. The catalysts were characterized by XRD, BET, TEM, Raman spectroscopy and TG-DTA analysis. The catalytic decomposition activities showed that a tremendous hydrogen production (∼90%) was obtained over 20–40wt%Ni/Mo–Al2O3 catalysts. Moreover, all catalysts exhibited excellent durability up to 9 h with stable catalytic activity toward H2 production. Although the increase of Ni content reduces the catalyst surface area, the H2 productivity and longevity increases with increased Ni content, i.e., the catalytic decomposition activity primarily depends on the active Ni sites which overcompensates the surface deficiencies. TEM, TGA and XRD data of used catalysts indicated that a higher thermal stability and graphitization degree of multi-walled carbon nanotubes were obtained on all Ni containing catalysts. Higher metal loading produced carbon nanofibers beside CNTs due to increment of particle size and long reaction time.

Solid-state reaction synthesized Pd-doped tin oxide thick film sensor for detection of H2, CO, LPG and CH4

This paper deals with the synthesis of tin oxide (SnO2) nano-powders by a solid-state reaction technique. The synthesized powders have been characterized by simultaneous thermo gravimetric and differential thermal analysis (TG–DTA) and X-ray diffraction (XRD) techniques. Suitable calcination temperature is established by XRD and TG–DTA analysis. Thick film sensors have been developed from as-prepared undoped and palladium (Pd) doped (0.5 and 1 wt%) SnO2 powders using screen printing technology for the detection of various pollutant gases such as, hydrogen (H2), carbon monoxide (CO), liquefied petroleum gas (LPG) and methane (CH4). The surface of the thick film sensor has been characterized by field emission scanning electron microscopy (FESEM). The sensing characteristics of thick films have been studied from the aspect of crystallite size of sensing material and microstructure of the thick film surface. It is found that SnO2 doped with 1 % Pd exhibits the maximum sensitivity (79 %) towards CO gas along with fast response/recovery time (80 s, 197 s) and almost insensitive for H2, LPG and CH4.

Temperature-induced phase transformations of the “glaserite” type zirconosilicate Na3HZrSi2O8·0.4H2O

DTA-TG and powder XRD analyses are used to study the occurring upon heating structural transformations of the “glaserite” type zirconosilicate Na3HZrSi2O8·0.4H2O. The title compound undergoes energetically favored irreversible topotactic dehydration within the temperature range 200 and 400°C. Essential structural transformations occur only after 700°C, however, the phase composition of the run-product strongly depends on the conditions of thermal treatment. In all cases the predominant phase at 1000°C is the NASICON type zirconosilicate – Na4Zr2Si3O12. The concomitant compound is either Na2SiO3 or the parakeldyshite synthetic analog – Na2ZrSi2O7. The mechanism of structural transformation and certain structural relationships are discussed in terms of the crystal chemical peculiarities of the initial compound and the run-products.