Thermogravimetric analysis dispersions

Cobalt-on-alumina catalysts with increased dispersion and catalytic activity are prepared by addition of mannitol to the cobalt nitrate solution prior to impregnation. Thermogravimetric analysis (TGA) and in situ visible microscopy of the impregnation solution show that the organic compound reacts with cobalt nitrate, forming a foam. The foam forms because significant amounts of gas are released through a viscous liquid. The structure of the foam is retained in the final calcined product. It is this effect that is responsible for the increased dispersion. 

The fresh and spent catalysts were characterized with the physisorption/chemisorption instrument Sorptometer 1900 (Carlo Erba instruments) in order to detect loss of surface area and pore volume. The specific surface area was calculated based on Dubinin-Radushkevich equation. Furthermore thermogravimetric analysis (TGA) of the fresh and used catalysts were performed with a Mettler Toledo TGA/SDTA 851e instrument in synthetic air. The mean particle size and the metal dispersion was measured with a Malvern 2600 particle size analyzer and Autochem 2910 apparatus (by a CO chemisorption technique), respectively. 

The impact of the nanocomposite technology on polymers is huge, reflected in enhanced properties of the resulting PNs, such as enhanced mechanical, barrier, solvent-resistant, and ablation properties.12 The effect of nanocomposite technology on the thermal and fire performance of the polymers is primarily observed in two important parameters of the polymers (1) the onset temperature (7( ,nsct) in the thermogravimetric analysis (TGA) curve—representative of the thermal stability of the polymer, and (2) the peak heat release rate (peak HRR) in cone calorimetric analysis (CCA)—a reflection of the combustion behavior (the flammability) of the polymer. The Tonset will be increased and the peak HRR will be reduced for a variety of polymers when nanoscale dispersion of the nanoadditive is achieved in the polymer matrix. 

Characterization. CHNS analysis was carried using the Thermo Finnigan FLASH EA 1112 CHNS analyzer. Energy dispersive analysis of X-rays (EDAX) was carried using the OXFORD ED AX system. Infrared spectroscopic studies of KBr pellets were recorded in the mid-IRregion (Bruker IFS-66v). Thermogravimetric analysis was carried out (Metler-Toledo) in nitrogen atmosphere (flow rate... 

I was characterized by powder X-ray diffraction (PXRD), energy dispersive analysis of X-rays (EDAX), chemical analysis, thermogravimetric analysis (TGA) and IR spectroscopy. EDAX analysis indicated the ratio of Mn S to be 3 2. The presence of fluorine was confirmed by analysis and the percentage of fluorine estimated by EDAX in a field emission scanning electron microscope was also satisfactory. Thermogravimetric analysis also confirms the stoichiometry of the compound. Bond valence sum calculations6 and the absence of electron density near fluorine in the difference Fourier map also provide evidence for the presence of fluorine. The sulfate content was found to be 30.8% compared to the expected 32% on the basis of the formula. 

It is shown that the applicability of fractal model of anomalous diffusion for quantitative description of thermogravimetric analysis results in case of high density polyethylene modified by high disperse mixture Fe/FeO (Z). It is shown the influence of diffusion type on the value of sample 5%-th mass loss temperature and was offered structural analysis of this effect. The critical content Z it is determined, at which degradation will be elapse so, as in inert gas atmosphere. 

The polypropylene continuous phase was transparent and epoxy phase appeared dark in the optical micrograph. However, the cause of elongated structure was not fully understood. The formation of elongated structure could be due to the friction between carbon black coated dispersed particles and the matrix (61), which decreased the interfacial tension between the immiscible polymers (63) or both (64). Based on extraction studies and thermogravimetric analysis, it was concluded that nearly all the carbon black particles were located in the epoxy matrix. 

Synthesized powders were calcined and characterized by standard techniques of thermogravimetric analysis, BET specific surface area measurements, and particle size determination by sedigraphy, as well as X-ray diffraction, and scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) for microchemical analyses. To... 

Resistance to environmental stress cracking - Measurement of the melt flow index -Carbon black and/or mineral filler content measurement in polyethy-lene by direct combustion - Measurement of carbon black content by thermogravimetric analysis (TGA) - Assessment of carbon black dispersion in polyethylene using a microscope... 

Blends of polyethylene terephthalate and linear low-density polyethylene were compatibilised using diethylmaleate grafted polyethylene, and characterised using Fourier transform infra-red spectroscopy, thermogravimetric analysis and scanning electron microscopy. Interactions between the components in the blends were observed, which affected the glycol sequences of the polyester and also improved the thermal oxidative stability of the blends. The introduction of the compatibiliser resulted in a particle size reduction of the dispersed phase and better adhesion between the phase and the matrix. 15 refs. 

Supri and Ismail [46] prepared modified and unmodified low-density polyethylene (LDPE) and mixed it with water hyacinth fiber (WHF) composites by melt blending. Tensile test, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and water absorption behavior test of the composites were conducted. The NCO-polyol-modified LDPE/AAfHF showed higher tensile strength, modulus of elasticity, and water absorption resistance as compared to the unmodified LDPE/WHF composites. However, the elongation at break was better when the LDPE was immodi-fied. Moreover, the modified LDPE/WHF offered better thermal properties in comparison to the unmodified LDPE/WHF. The NCO-polyol was reported to create better dispersion of WHF in the LDPE matrix. 

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