Ionic transport through a composite structure of N-ethyl-N-methylpyrrolidinium tetrafluoroborate organic ionic plastic crystals reinforced with polymer nanofibres

The incorporation of polyvinylidene difluoride (PVDF) electrospun nanofibres within N-ethyl-N-methylpyrrolidinium tetrafluoroborate, [C2mpyr][BF4] was investigated with a view to fabricating self-standing membranes for various electrochemical device applications, in particular lithium metal batteries. Significant improvement in mechanical properties and ionic conduction was demonstrated in a previous study, which also demonstrated the remarkably high performance of the lithium-doped composite material in a device. We now seek a fundamental understanding of the role of fibres within the matrix of the plastic crystal, which is essential for optimizing device performance through fine-tuning of the composite material properties. The focus of the current study is therefore a thorough investigation of the phase behaviour and conduction behaviour of the pure and the lithium-doped (as LiBF4) plastic crystal, with and without incorporation of polymer nanofibres. Analysis of the structure of the plastic crystal, including the effects of lithium ions and the incorporation of PVDF fibres, was conducted by means of synchrotron XRD. Ion dynamics were evaluated using VT solid-state NMR spectroscopy. ATR-FTIR spectroscopy was employed to gain insights into the molecular interactions of doped lithium ions and/or the PVDF nanofibres in the matrix of the [C2mpyr][BF4] composites. Preliminary measurements using PALS were conducted to probe structural defects within the pure materials. It was found that ion transport within the plastic crystal was significantly altered by doping with lithium ions due to the precipitation of a second phase in the structure. The incorporation of the fibres activated more mobile sites in the systems, but restricted ion mobility with different trends being observed for each ion species in each crystalline phase. In the presence of the fibres a strong interaction observed between the Li ion and the pyrrolidinium ring disappeared and formation of the second phase was prevented. As a result, an increased number of mobile lithium ions are released into the solid solution structure of the matrix, simultaneously removing the blocking effect of the second phase. Thus, ion conduction was remarkably improved within the Li-doped composite compared to the neat Li-doped plastic crystal.

Genotoxicidade e composição do material particulado emitido pela queima de Biomassa: um estudo de caso em Tangará da Serra, Região da Amazônia Brasileira

Tangara da Serra is located on southwestern Mato Grosso and is found to be on the route of pollutants dispersion originated in the Legal Amazon s deforestation area. This region has also a wide area of sugarcane culture, setting this site quite exposed to atmospheric pollutants. The objective of this work was to evaluate the genotoxicity of three different concentrations of organic particulate matter which was collected from August through December / 2008 in Tangara da Serra, using micronucleus test in Tradescantia pallida (Trad-MCN). The levels of particulate matter less than 10μm (MP10) and black carbon (BC) collected on the Teflon and polycarbonate filters were determined as well. Also, the alkanes and polycyclic aromatic hydrocarbons (PAHs) were identified and quantified on the samples from the burning period by gas chromatography detector with flame ionization detection (GC-FID). The results from the analyzing of alkanes indicate an antropic influence. Among the PAHs, the retene was the one found on the higher quantity and it is an indicator of biomass burning. The compounds indene(1,2,3-cd)pyrene and benzo(k)fluoranthene were identified on the samples and are considered to be potentially mutagenic and carcinogenic. By using Trad-MCN, it was observed a significant increase on the micronucleus frequency during the burning period, and this fact can be related to the mutagenic PAHs which were found on such extracts. When the period of less burnings is analyzed and compared to the negative control group, it was noted that there was no significant difference on the micronuclei rate. On the other hand, when the higher burning period is analyzed, statistically significant differences were evident. This study showed that the Trad-MCN was sensible and efficient on evaluating the genotoxicity potencial of organic matter from biomass burning, and also, emphasizes the importance of performing a chemical composition analysis in order to achieve a complete diagnosis on environmental risk control

Dielectric properties of thermosetting material nanocomposites

The dieletric relaxation properties of thermosetting material nanocomposites based on spherosilicate nanoplatforms were studied from room temperature to 170 degrees C, varying the frequency from 10 to 1000 KHz. Permittivity (epsilon'), dielectric loss (epsilon ''), and activation energy (E-a) were calculated. The results of dielectric relaxation were confirmed by those of the final properties. The dielectric loss amplitude decreases with increasing ODPG content until about 70-73 wt % and slightly increases at higher ODPG content. This means that the increasing of the ODPG content in the composite samples decreases the number of pendants groups and/or increases crosslink densitv, causing decreased motion of organic tethers, and subsequently decreasing of the dipolar mobility. The results of apparent activation energy, fracture toughness and tensile modulus mechanical properties show the same profile with respect to ODPG content, in the sense that they exhibit maxima around 70 wt % ODPG. For the ODPG/MDA composites, this formulation of 70 wt % ODPG containing excess of amine is not composition where the highest crosslinked density is reached. This implies that the best mechanical properties and E-a are provided by some degree of chain flexibility. (c) 2007 Wiley Periodicals, Inc.

Characterization of Post-Consumer PET after Removal of the Original Surface: Influence of Raw Material

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

Cobre e zinco no material percolado e no solo com a aplicação de água residuaria de suinocultura em solo cultivado com soja

O objetivo deste trabalho foi avaliar possíveis efeitos da aplicação de taxas de água residuária de suinocultura (ARS), quanto às concentrações de cobre e zinco, tanto no solo quanto na água percolada de lisímetros de drenagem, durante o ciclo da cultura da soja. O experimento foi conduzido em ambiente protegido, onde havia 24 lisímetros de drenagem. Semeou-se soja cultivar CD 202, e foram aplicadas ARS nas seguintes dosagens: 0; 100; 200 e 300 m³ ha-1 no ciclo, combinadas com duas adubações na semeadura (com e sem adição da adubação recomendada na semeadura), em três repetições por tratamento. Foram feitas seis coletas do material percolado durante o ciclo da cultura e realizadas determinações de cobre e zinco. No solo, foram feitas três coletas em cada parcela experimental, para a determinação do pH, da matéria orgânica, da capacidade de troca catiônica, do cobre e do zinco. O delineamento foi em blocos casualizados, num esquema fatorial de 4 x 2. Observou-se que o cobre no solo não apresentou diferenças significativas com a aplicação de ARS e adubação, enquanto as concentrações de zinco no solo foram influenciadas pelas taxas aplicadas de ARS. As transferências de cobre e de zinco por percolação foram pouco expressivas.

NOVEL CELLULOSE/NbOPO4 center dot nH(2)O HYBRID MATERIAL FROM SUGARCANE BAGASSE

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

Antigen otoxicity of Agaricus blazei mushroom organic and aqueous extracts in chromosomal aberration and cytokinesis block micronucleus assays in CHO-k1 and HTC cells

Agaricus blazei (Ab) has become popularly known for its medicinal properties. Scientifically, it has been tested with regard to its capacity to protect genetic material against damage. We examined different organic extracts (methanolic extract-ME, hexanic extract-HE and n-butanolic extract-BE) and an aqueous extract (AE) of Ab, for their capacity to induce DNA damage as well as for their protective effect. Genetic damage was determined by the chromosomal aberration assay (CA) in CHO-k1 cells for all extracts and the cytokinesis block micronucleus assay (CBMN) in non drug-metabolizing (CHO-k1) and drug-metabolizing (HTC) cell lines for extract BE only. The extracts did not show clastogenicity but showed anticlastogenicity. The greatest percent reduction obtained were with BE (105%) and AE (126%) treatments in CA. BE treatment did not display genotoxicity in CHO-k1, but was genotoxic in HTC. However, BE was shown to be antigenotoxic causing decreased micronucleus frequency in HTC and CHO-k1 cells. These results suggest that all the extracts contained protective substances, but in some cases they could show a genotoxic effect with regard to metabolism. Therefore, these findings warrant caution in the use of this mushroom by the population. (c) 2005 Elsevier Ltd. All rights reserved.

Modeling of organic light-emitting diodes with graded concentration in the emissive multilayer

We model the electrical behavior of organic light-emitting diodes whose emissive multilayer is formed by blends of an electron transporting material, tris-(8-hydroxyquinoline) aluminum (Alq(3)) and a hole transporting material, N,N-'-diphenyl-N,N-'-bis(1,1(')-biphenyl)-4,4-diamine. The multilayer is composed of layers of different concentration. The Alq(3) concentration gradually decreases from the cathode to the anode. We demonstrate that these graded devices have higher efficiency and operate at lower applied voltages than devices whose emissive layer is made of nominally homogeneous blends. Our results show an important advantage of graded devices, namely, the low values of the recombination rate distribution near the cathode and the anode, so that electrode quenching is expected to be significantly suppressed in these devices. (C) 2004 American Institute of Physics.

Desenvolvimento e aplicação de método GC-MS/MS para análise simultânea de 17 HPAs em material particulado atmosférico

Os hidrocarbonetos policíclicos aromáticos (HPAs) estão associados ao aumento da incidência de diversos tipos de cânceres no homem. Essas moléculas são formadas principalmente na queima incompleta de matéria orgânica, sendo encontradas em todos os compartimentos ambientais. Órgãos regulamentadores das áreas ambiental e de saúde ocupacional consideram 17 HPAs como contaminantes atmosféricos prioritários. Este trabalho apresenta um método para análise simultânea destes HPAs utilizando-se a cromatografia a gás acoplada à espectrometria de massas operando no modo tandem (GC-MS/MS). Os limites de detecção e quantificação do método mostraram-se até 5 vezes inferiores aos obtidos no método GC-MS (SCAN). O método mostrou-se seletivo para análise de HPAs em extratos de amostras de material particulado atmosférico. Uma análise comparativa de dois sistemas de solventes (diclorometano/metanol 4:1 v/v e hexano/acetona 1:1 v/v) para a extração de HPAs, utilizando amostras de material particulado atmosférico, revelou que ambas as misturas de solventes possuem poder de extração semelhante. Os resultados sugerem que é possível realizar extração de HPAs de material particulado atmosférico em ultra-som com a mistura hexano/acetona (1:1), que é menos tóxica em relação à mistura diclorometano/metanol (4:1), bastante utilizada nestas análises, sem perdas significativas na exatidão do método.

Influência do material do alambique na composição química das aguardentes de cana-de-açúcar

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

Production of yacon plantlet (Polymnia sonchifolia poep. et endl.) in different organic fertilization

The work was carried out in nursery of the Agronomical Science College (ASC) UNESP-Botucatu, in period from September 21(st) to October 31(st) 2000. The propagation material (rhizophores) was obtained from plants, which were cultivated in the area of ASC. The rhizophores were selected according to their vigor and size. Healthy rhizophores were chosen between 15 and 25 g, which were treated with benomil (0,6%, 10 minutes). As a basic commercial substratum Solomix((R)) was used with mixing cattle manure and chicken manure in the following proportions: T1- pure substratum; T2 - substratum + cattle manure (1:1), T3- substratum + cattle manure (2:1); T4- substratum + chicken manure (4:1). The yacon rhizophores presented good shoots in all substrata with exception of T4. For all parameters no significant difference between the pure commercial substratum and its mixture with cattle manure were observed; however, the addition the chicken manure in the studied proportions revealed harmful effect on the survival and development of the plantlets. The results indicated, that the viability of smaller size rhizophores was higher as the size conventionally used in Brazil (60 to 80 g).

Nanostructured organic layers via polymer demixing for interface-enhanced photovoltaic cells

Significant progress is being made in the photovoltaic energy conversion using organic semiconducting materials. One of the focuses of attention is the morphology of the donor-acceptor heterojunction at the nanometer scale, to ensure efficient charge generation and loss-free charge transport at the same time. Here, we present a method for the controlled, sequential design of a bilayer polymer cell architecture that consists of a large interface area with connecting paths to the respective electrodes for both materials. We used the surface-directed demixing of a donor conjugated/guest polymer blend during spin coating to produce a nanostructured interface, which was, after removal of the guest with a selective solvent, covered with an acceptor layer. With use of a donor poly(p-phenylenevinylene) derivative and the acceptor C-60 fullerene, this resulted in much-improved device performance, with external power efficiencies more than 3 times higher than those reported for that particular material combination so far.

Organic-inorganic hybrids prepared by carboxylic acid solvolysis: Planar waveguides

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

Influence of cerium (IV) ions on the inorganic and organic phase for preparation of a siloxane-PMMA based film on tin plate substrate

Tinplate is one of the most widely used food canning materials, however, there are significant problems related to the use of tinplate cans, such as alterations in sensory features affecting food quality and corrosion phenomena of the canning material. To avoid corrosion problems different methods have been used for the passivation of tinplate such protective lacquers or different kinds of corrosion inhibitors (chromate and dichromate). However, chromates and dichromates are extremely harmful to the environment and can cause carcinogenic tumors to humans. An option, protective coatings obtained by the sol-gel process, act as a physical barrier, which isolates the surface of metal protecting from the corrosive agents. The aim of this work is to study the influence of addition of cerium (IV) ions in the inorganic and organic part of sol-gel processing in the formation of hybrid coatings based on siloxane-PMMA on tin plate. The coatings were obtained by dip-coating technique and evaluated by open circuit and impedance measurements, linear polarization and polarization curves obtained in 3.5% NaCl solution. The results have clearly shown the improvement on the protective properties of the Ce 4+ modified film when added into the organic phase, which can be due to the formation of a more uniform and densely reticulated siloxane-PMMA film. © 2009 by NACE International.

Novel cellulose/NbOPO 4.nH 2O hybrid material from sugarcane bagasse

In recent years studies concerning the applications of lignocellulosic/ inorganic couples have resulted in the development of an interesting class of functional materials. In this work a cellulose/NbOPO 4.nH 2O hybrid using cellulose from surgacane bagasse was prepared and characterized in order to test for adsorption applications. The preparation process was conducted by carrying out metallic niobium dilution in hydrofluoric acid in the presence of nitric acid, then adding boric acid to form the complex and, finally, the cellulose sugar cane bagasse was added. Concentrated phosphoric acid was also inserted to precipitate hydrous niobium phosphate particles in the cellulose fiber. This material was characterized by X-ray diffractometry (XRD), thermogravimetry (TG/DTG), and scanning electronic microscopy (SEM) connected to an energy dispersive spectrophotometer (EDS). Results by SEM/EDS show that NbOPO 4.nH 2O was present in structure of the cellulose. During the preparation of the material, using boric acid it was observed that the formation of precipitate occurred in a shorter time than the material prepared without boric acid.