Ciprofloxacin Release Using Natural Rubber Latex Membranes as Carrier

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Characterization of corn (Zea mays) leaf powder and Its adsorption properties regarding Cu(II) and Cd(II) from aqueous samples

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

Characterization of typical aquatic humic substances in areas of sugarcane cultivation in Brazil using tetramethylammonium hydroxide thermochemolysis

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

NIRS and iSPA-PLS for predicting total anthocyanin content in jaboticaba fruit

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fragmentation of lignin from organosolv black liquor by white rot fungi

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Luminescence properties of Eu-complex formations into ordered mesoporous silica particles obtained by the spray pyrolysis process

Ordered mesoporous, highly luminescent SiO2 particles have been synthesized by spray pyrolysis from solutions containing tetraethylorthosilicate (TEOS), Eu(NO3)3.6H2O, and cetyltrimethylammonium bromide (CTAB) as structure-directing agents. The 1,10-phenantroline (Phen) molecules were coordinated in a post-synthesis step by a simple wet impregnation method. In addition, other matrices were also prepared by the encapsulation of europium complex Eu(fod)3 (where fod = 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato) into mesoporous silica, and then the Phen molecules were encapsulated by different impregnation steps, after which the luminescence properties were investigated. The obtained materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder x-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Powders with polydisperse spherical grains were obtained, displaying an ordered hexagonal array of mesochannels. Luminescence results revealed that Phen molecules had been successfully coordinated as an additional ligand in the Eu(fod)3 complex into the channels of the mesoporous particles without disrupting the structure.

Compostos de paládio(II) contendo ligantes N,S-quelantes: síntese, caracterização e investigação da atividade biológica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Deriving the magnitude of niobium off-center displacement in ferroelectric niobates from infrared spectroscopy

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Structural phase transitions of PbZr0.52Ti0.48O3 ceramic: An infrared spectroscopy study

The recent discovery of a ferroelectric monoclinic phase in the PbZr1-xTixO3 (PZT) system attained the attention of several researchers due to the possibility of understanding the relationships between structural features and piezoelectric properties. The nature of the monoclinic phase in some PZT compositions remains controversial and unclear. In this work, structural phase transitions of PbZr0.52Ti0.48O3 ceramic were investigated by infrared spectroscopy as a function of temperature. Studies were centered on nu(1)-stretching modes and corresponding half width Wi as a function of temperature. The occurrence of the anomalies in the infrared spectra as a function of temperature suggests the following monoclinic ( LT) -> monoclinic ( HT) -> tetragonal phase transition were observed at 183 K and at 263 K.

Monoclinic-tetragonal phase transition in Pb(Zr1-xTix)O-3 studied by infrared spectroscopy

The discovery of a new monoclinic phase in the PbZr1-xTixO3 (PZT) system in the vicinity of the morphotropic phase boundary (MPB), previously considered as a region where the rhombohedral and tetragonal phases of PZT coexist, was recently reported. Investigations of this new phase were reported using different techniques such as high-resolution synchrotron x-ray powder diffraction and Raman spectroscopy. The main objective has been to define a new phase diagram of PZT. In this context, infrared spectroscopic studies were performed in the vicinity of the MPB and studies were initially centred on a PZT sample with x = 0.49 mol% Ti content. Results suggested that the monoclinic --> tetragonal phase transition occurs at 237 K, confirming the use of IR as a useful technique to investigate this phase transition.

Structural Phase Transition Studies on PMN-0.35PT using Infrared Spectroscopy

The purpose of the present work is to report studies on structural phase transition for PMN-xPT ferroelectric, with melt PbTiO3 composition around the MPB (x = 0.35 mol %), using infrared spectroscopy technique. The study was centered on monitoring the behavior of the 1-(NbO), 1-(TiO) and 1-(MgO) stretching modes as a function of temperature. The increasing as a function of temperature for 1-(TiO) and 1-(MgO) modes, observed between 230 and 300 K, can be related to the monoclinic (MC) + tetragonal (T) phase coexistence in the PMN-PT.

Infrared spectroscopy: a tool for determination of the degree of conversion in dental composites

Infrared spectroscopy is one of the most widely used techniques for measurement of conversion degree in dental composites. However, to obtain good quality spectra and quantitative analysis from spectral data, appropriate expertise and knowledge of the technique are mandatory. This paper presents important details to use infrared spectroscopy for determination of the conversion degree.

Action of soil microorganisms on PCL and PHBV blend and films

Poly(hydroxybutyrate-co-valerate) (PHBV) and poly(epsilon-caprolactone) (PCL) PCL/PHBV (4:1) blend films were prepared by melt-pressing. The biodegradation of the films in response to burial in soil for 30 days was investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetry (TG). The PHBV film was the most susceptible to microbial attack, since it was rapidly biodegraded via surface erosion in 15 days and completely degraded in 30 days. The PCL film also degraded but more slowly than PHBV. The degradation of the PCL/PHBV blend occurred in the PHBV phase, inducing changes in the PCL phases (interphase) and resulting in an increase of its crystalline fraction.

Synthesis, Infrared Spectroscopy and Crystal Structure Determination of a New Decavanadate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Study of the biodegradation of a polymer derived from castor oil by scanning electron microscopy, thermogravimetry and infrared spectroscopy

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)