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91.
S. Ľalíková M. Pajtášová M. Chromčíková M. Liška V. Šutinská M. Olšovský D. Ondrušová S. C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2011,104(3):969-973
This paper is devoted to the investigation of the properties of the natural rubber composites prepared using the cation exchanged-montmorillonite
fillers. The characteristics of the montmorillonite fillers were studied by Fourier transform infrared spectroscopy (FTIR)
and thermogravimetry (TG). These characterized fillers were used to preparation of the natural rubber composites, which were
submitted to measurements of dynamic-mechanical thermal analysis (DMTA) and vulcanizing characteristics (M
H, M
L, t
s, t
c(90), R
v) as well as physico-mechanical properties (tensile strength, modulus at 300 elongation—M
300, tensibility). 相似文献
92.
93.
94.
K. Muthu G. Bhagavannarayana V. Meenatchi S. P. Meenakshisundaram S. C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2012,108(3):951-958
In this article, the effect of magnesium doping on the properties of bis(thiourea)zinc(II) chloride (BTZC) crystals has been described. The incorporation of Mg(II) into the crystal lattice was confirmed by energy dispersive X-ray spectroscopy and quantified by inductively coupled plasma technique. The powder X-ray diffraction and FT-IR spectral analyses indicate that the crystal undergoes considerable stress as result of doping. SEM studies of pure and doped samples indicate the formation of structural defect centers in BTZC crystals. The TG?CDTA studies reveal the purity of the materials, and no decomposition is observed up to the melting point. Improved crystalline perfection by doping is observed by high-resolution X-ray diffraction. High transmittance is observed, and the cutoff ?? is ~295?nm. 相似文献
95.
G. Madhurambal B. Ravindran M. Mariappan K. Ramamurthi S. C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2011,104(3):875-878
A single crystal of cinnamic acid–urea was grown by slow evaporation of methanol solution at room temperature. In this research,
many analytical methods such as FTIR, second harmonic generation, NMR, and TG–DTA were used. The presence of title compound
in the crystal lattice has been qualitatively determined by FTIR analysis. Thermal stability of the grown crystals was evaluated
by TG-DTA. Incorporation of urea increases the thermal stability insuring the suitability of material for possible non-linear
optical application up to 180 °C. 相似文献
96.
G. Madhurambal B. Ravindran M. Mariappan S. C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2010,100(3):811-815
A single crystal of sodium and potassium cinnamates was grown by slow evaporation of methanol solution at room temperature. The effect of metals sodium and potassium on the electronic structure of cinnamic acid was studied. In this research many analytical methods such as FTIR, UV, second harmonic generation (SHG) and TG–DTA were used: The spectroscopic studies lead to conclusions containing the distribution of the electronic charge in molecule, the delocalisation of π electrons and the reactivity of metal complexes. The SHG efficiency is more pronounced in the presence of sodium and potassium dopant in the growth medium. Incorporation of sodium and potassium increase the thermal stability ensuring the suitability of material for possible non-linear optical (NLO) application up to 180 °C. 相似文献
97.
S. P. Meenakshisundaram S. Parthiban R. Kalavathy G. Madhurambal G. Bhagavannarayana S. C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2010,100(3):831-837
The influence of heteroaromatic N-base (1,10-phenanthroline) (Phen), a new additive as complexing agent on tris(thiourea)zinc(II)sulphate (ZTS) crystals from aqueous solutions at 30 °C is investigated. Crystals were grown using low concentration of the dopant (0.005 M L?1) in the aqueous growth medium and the growth promoting effect (GPE) is much greater because of an increase in the metastable zone width. High dopant concentration decreases GPE. The crystalline perfection of the grown crystals is quite good both in doped and undoped crystals as evaluated by high-resolution X-ray diffractometry (HRXRD). The diffraction curve of a typical Phen doped as-grown ZTS crystal was observed to contain a single peak indicating that the crystal does not contain any epitaxial layer on the surface or internal structural grain boundaries. Not much variation is observed in FT-IR and XRD of pure and doped ZTS. Phen depresses the NLO efficiency of ZTS. It could be ascribed due to the disturbance of charge transfer in the presence of the dopant. The grown crystals were also characterized by UV–Vis, SEM and TG–DTA techniques. 相似文献
98.
S. Parthiban S. Murali G. Madhurambal S. P. Meenakshisundaram S. C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2010,100(3):751-756
The influence of doping the transition metal Zn(II) on potassium hydrogen phthalate (KHP) crystals has been studied. A close observation of FT-IR and XRD profiles of doped and undoped samples reveals some minor structural variations. It appears that the crystal undergoes considerable lattice stress as a result of doping the bivalent zinc. Furthermore, the possibility of cation vacancies aroused owing to the substitution of K1+ by Zn2+ could result in a defective crystal system. Energy dispersive spectra reveal the incorporation of Zn(II) in the crystalline matrix of KHP crystals. Differential scanning calorimetry (DSC) and TG-DTA studies reveal the purity of the sample and no decomposition is observed below the melting point. Small quantity additions of Zn(II) enhance the fluorescence intensity of KHP crystals. The doping results in morphological changes and significantly improves the second harmonic generation (SHG) efficiency of the host crystal. 相似文献
99.
U. B. Gawas S. C. Mojumdar V. M. S. Verenkar 《Journal of Thermal Analysis and Calorimetry》2010,100(3):867-871
Manganese zinc ferrous fumarato–hydrazinate precursor, Mn0.6Zn0.4Fe2(C4H2O4)3·6N2H4 was synthesized for the first time and characterized by chemical analysis, infrared spectral studies, and thermal analysis. Infrared studies show band at 977 cm?1 indicating bidentate bridging nature of the hydrazine in the complex. Thermogravimetric (TG) studies show two steps dehydrazination followed by two steps total decarboxylation. The precursor on touching with burning splinter undergoes self propagating autocatalytic decomposition yielding ultrafine Mn0.6Zn0.4Fe2O4. XRD studies confirms single phase formation as well as nanosize nature of “as prepared” Mn0.6Zn0.4Fe2O4. The saturation magnetization of the “as prepared” Mn0.6Zn0.4Fe2O4 was found to be 31.46 emu gm?1, which is lower than the reported, confirms the ultrafine nature of the oxide. 相似文献
100.
S. Lendvayová K. Moricová E. Jóna J. Kraxner M. Loduhová V. Pavlík J. Pagá?ová S. C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2012,108(3):901-904
A criterion based on the length of induction period of crystallization was used to evaluate the thermal stability of M2O·SiO2 (M?=?Li, Na) glasses against crystallization. It was founded out that the stability of studied glasses against crystallization is Li2O·SiO2?<?Na2O·SiO2. The results coincide with the order determined by stability criteria based on temperatures and the values of activation energy. A criterion based on the length of induction period enables to discriminate among the thermal stabilities of the silicate glass systems. 相似文献