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initiated with the preparation, spectral characterization and thermal analyses of the complexes of metal with relevant ligands. Experimental Apparatus and reagents All the used chemicals and solvents were of A

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Potassium acid phthalate (KAP) which is also known as potassium hydrogen phthalate (KC8H5O4), a semi-organic compound was grown from its aqueous solution only by slow evaporation method at room temperature. The effect of metallic salts HgCl2 and PbCl2 as dopants in the growth aspects, thermal properties and SHG efficiency of KAP were determined using UV-VIS, FTIR spectral studies, thermal (TG and DTA) analysis and NLO test. There is only one significant mass loss step on TG curve of pure and doped KAP crystal. DTA curve exhibit a higher peak temperature in case of doped KAP crystal compared to those of pure KAP crystals.

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Bio-composite fibers were developed from wood pulp and polypropylene (PP) by an extrusion process. The thermo-physical and mechanical properties of wood pulp-PP composite fibers, neat PP and wood pulp were studied using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The thermal stability of bio-composite fibers was found to be significantly higher than pure wood pulp. An understanding into the melting behaviour of the composite system was obtained which would assist in selecting a suitable temperature profile for the extruder during processing. The visco-elastic properties of bio-composite fibers were also revealed from the study. The generated bio-composite fibers were also characterized using Fourier transform infrared spectroscopy (FTIR) to understand the nature of chemical interaction between wood pulp reinforcement and PP matrix. The use of maleated polypropylene (MAPP) as a compatibilizer was investigated in relation to the fiber microstructure. Changes in absorption peaks were observed in FTIR spectra of bio-composite fibers as compared to the pure wood pulp which indicated possible chemical linkages between the fiber and polymer matrix.

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Zirconyl complexes of hippuric acid (C9H9NO3, hipH) and monophenylbutazone (4-butyl-1-phenyl-3,5-pyrazolidinedione, MPB) were prepared using ZrOCl2 · 8H2O and ZrO(NO3)3 · xH2O and characterized by elemental analysis, molar conductance measurement and IR, UV–Vis and NMR spectral methods. Thermal decomposition behaviour was studied by thermogravimetry. The second harmonic generation (SHG) conversion efficiency of hippuric acid complexes was also studied.

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A new chelate (η5-C5H5)2Ti(SB)2, whereSB=O, N donor Schiff base salicylidene-4-methylaniline, was synthesized. The course of thermal degradation of the chelate was studied by thermogravimetric (TG) and differential thermal analysis (DTA) under dynamic conditions of temperature. The order of the thermal decomposition reaction and energy of activation was calculated from TG curve while from DTA curve the change in enthalpy was calculated. Evaluation of the kinetic parameters was performed by Coats-Redfern as well as Piloyan-Novikova methods which gaven=1, ΔH=1.114 kJ·mol−1, ΔE=27.01 kJ·mol−1, ΔS=−340.12 kJ·mol−1·K−1 andn=1, ΔH=1.114 kJ·mol−1, ΔE=20.01 kJ·mol−1, ΔS=−342.60 kJ·mol−1·K−1, respectively. The chelate was also characterized on the basis of different spectral studies viz. conductance, molecular weight, IR, UV-visible and1H NMR, which enabled to propose an octahedral structure to the chelate.

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Four novel azo compounds were synthesized: o-phenylazo-(C14H13N3O2) (I), p-bromo-o-phenylazo-(C14H13BrN3O2) (II), p-methoxy-o-phenylazo-(C15H16N3O3) (III), and p-nitro-o-phenylazo-p-acetamidophenol (C14H13N4O4) (IV). These compounds were carefully investigated using elemental analyses, IR, and thermal analyses (TA) in comparison with electron ionization (EI) mass spectral (MS) fragmentation at 70 eV. Semi-empirical MO calculation, PM3 procedure, has been carried out on the four azo dyes (I–IV), both as neutral molecules and the corresponding positively charged molecular ions. These included molecular geometries (bond length, bond order, and charge distribution, heats of formation, and ionization energies). The mass spectral fragmentation pathways and thermal decomposition mechanisms were reported and interpreted on the basis of molecular orbital (MO) calculations. They are found to be highly correlated to each other. Also, the Hammett’s effects of p-methoxy, p-bromo, and p-nitro-substituents of phenyl azo groups on the thermal stability of these dyes (I–IV) are studied by experimental (TA and MS) in comparison with MO calculations, and the data obtained are discussed. This research aimed chiefly to throw more light on the structures of the four prepared azo derivatives of acetoamidophenol (p-cetamol). The data refering to the thermal stability of these dyes can be used in industry for effective dyeing purposes under different thermal conditions.

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Abstract  

Thermogravimetry is often used to study polymer degradation. Most often the information obtained may have some practical application but is of limited value for the determination of fundamental processes which may be occurring. A kinetic expression or activation parameters for a complex process which may involve consecutive or parallel reactions provides almost no information about any of the reactions that might be occurring. However, for single, well-defined processes, thermogravimetry, in conjugation with other analytical methods, can be effectively utilized in the determination of reaction mechanism. The thermal degradation of vinylidene chloride barrier polymers corresponds to the elimination of hydrogen chloride initiated at an allylic dichloromethylene unit in the mainchain. This process is uncomplicated by competing reactions. Thermogravimetry may be utilized to obtain meaningful rate constants and activation parameters for the degradation. This in conjunction with mass spectral analysis of evolved gas, characterization of both the polymer and degradation residue by ultraviolet, infrared and 1H and 13C NMR spectroscopy, and the study of model compounds has permitted a detailed description of the degradation process. General purpose poly(styrene) is a commodity polymer widely used in the food packaging industry as well as many others. If processed at excessively high temperature, it undergoes thermal degradation to expel styrene monomer which can impart negative flavor and aroma characteristics to packaged food items. The degradation reaction has been fully detailed using thermogravimetry in conjugation with evolved gas analysis, size exclusion chromatography and NMR spectroscopy.

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, D. , Kanimozhi , K. , Bhuvaneshwari , N. , Indira , J. & Kavitha , L. ( 2014 ): Novel banana peel pectin mediated green route for the synthesis of hydroxyapatite nanoparticles and their spectral characterization . Spectrochim. Acta A

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, Mojumdar , SC 2009 Thermal analysis, effect of dopants, spectral characterisation and growth aspects of KAP crystals . J Therm Anal Calorim 96 : 99 – 102 10.1007/s10973-008-9880-7 . 8

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