Structure and thermal behavior of PMMA-polysilsesquioxane organic-inorganic hybrids

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Thermal Characteristics of Lignin Residue from Industrial Processes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Home Cooking and Phenolics: Effect of Thermal Treatment and Addition of Extra Virgin Olive Oil on the Phenolic Profile of Tomato Sauces

Tomato products are a key component of the Mediterranean diet, which is strongly related to a reduced risk of cardiovascular events. The effect of cooking time (15, 30, 45, and 60 min) and the addition of extra virgin olive oil (5 and 10%) on the phenolic content of tomato sauces was monitored using liquid chromatography coupled to tandem mass spectrometry. Concentration of phenolics in the tomato sauces decreased during the cooking process, with the exception of caffeic acid and tyrosol. The main degradation observed was the oxidation of quercetin, since the hydroxy-function at the C-ring of this flavonoid is not blocked by a sugar moiety, unlike rutin. Higher levels of virgin olive oil in tomato sauce seemed to enhance the extraction of phenolic compounds from the tomato, leading to higher phenolic contents in the sauces. Thus, the food matrix containing the phenolic compounds plays a crucial role in determining their accessibility.

The Effects of Weathering Exposure on the Physical, Mechanical, and Thermal Properties of High-density Polyethylene and Poly (Vinyl Chloride)

This paper presents results describing the physical, mechanical, and thermal properties (melt flow index - MFI and oxidative induction time - OIT) of high density polyethylene and poly (vinyl chloride) after weathering exposure (6, 12, 18, and 30 months). The materials exposed were geomembranes of two thicknesses: 1.0 and 2.0 mm (PVC) and 0.8 and 2.5 mm (HDPE). The climate parameters (average) obtained were 25 degrees C (temperature), 93 mm (precipitation), 66% (relative humidity), and 19 MJ/m(2). day (intensity of global radiation). Some results showed, for instance, that the behavior of the geomembranes changed after the exposures. A few minor variations in physical properties occurred. The density and thickness, for instance, varied 0.5-1.0% (average) for both the PVC and HDPE geomembranes. The mechanical properties changed as a function of the period of exposure. In general, some decreases were verified by the deformation of PVC. The samples became more rigid. In contrast, HDPE geomembranes became more ductile. Despite the variations in elasticity, some increases in deformability were verified. An MFI test showed some degradation in HDPE geomembranes. OIT tests revealed small values for both intact and exposed samples.

Benzoxazine Resin/Carbon Nanotube Nanostructured Composite's Degradation Kinetic

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis, characterization, and thermal behavior of palladium(II) complexes containing 4-iodopyrazole

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Characterization and thermal study of organic extracts of urban solid waste

The urban residues put in landfill of the city of Sa˜o Carlos-SP, Brazil, in 2004 represent 58.7 % of decomposed organic material. The aim of this research was to characterize samples of urban solid waste and its organic extracts targeting the use of this residue without damaging the environment. The curves were obtained in a nitrogen atmosphere, a heating rate of 20 C min-1 , the temperature of 30–600 C. In the original sample after humidity loss, an event occured concerning the water constitution in the TG curve with an endothermic peak in the DTA curve. There was a presence of inorganic residue in the ashes. The organic matter present in the USR sample disposed in the landfill is constituted by several polarity, organics compounds from the degradation of lignin, cellulose, lipids, and other materials which thermal stabilities are distinct. The hexane extract features in its constitution two fatty acids, stearic and triacontano´ic, which are nonpolar compounds originating from bacteria present in the residue. The acids groups in extract hexane also were evidenced by X-ray diffraction and FTIR.

A stability-indicating LC method for difloxacin in the presence of degradation products

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation and degradation chemistry of orbifloxacin using LC-MS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Thermal, spectroscopic and DFT studies of solid benzamide

Thermogravimetry (TG), differential thermal analysis (DTA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and DFT theoretical calculations were used to study benzamide. The TG-DTA and DSC curves provided information concerning the melting point, evaporation and thermal stability of the compound. Using the FTIR technique it was possible to confirm the evaporation of the compound with no degradation. Density functional theory (DFT) at the 6-311++G (3df, 3dp) level, provided information regarding the energies involved in HOMO-LUMO transitions and the chemical stability of the compound.