Roughness and morphology of composites: influence of type of material, fluoride solution, and time

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Fluorescence Intensity of Composite Layering Combined with Surface Sealant Submitted to Staining Solutions

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

Encapsulation of paclitaxel into a bio-nanocomposite. a study combining inelastic neutron scattering to thermal analysis and infrared spectroscopy

The anticancer drug paclitaxel was encapsulated into a bio-nanocomposite formed by magnetic nanoparticles, chitosan and apatite. The aim of this drug carrier is to provide a new perspective against breast cancer. The dynamics of the pure and encapsulated drug were investigated in order to verify possible molecular changes caused by the encapsulation, as well as to follow which interactions may occur between paclitaxel and the composite. Fourier transformed infrared spectroscopy, thermal analysis, inelastic and quasi-elastic neutron scattering experiments were performed. These very preliminary results suggest the successful encapsulation of the drug.

Thermal degradation and lifetime estimation of poly(ether imide)/carbon fiber composites

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Synthesis and characterization of nanostructured TiO2-SnO2 composite

Nanostructured composites based on titanium dioxide have been studied in order to improve optical and photo-catalytic properties, as well as their performance in gas sensors. In this work, titanium and tin dioxides were simultaneously synthesized by the polyol method resulting in TiO2 platelet coated with SnO2 nanoparticles as was observed by scanning electron microscopy. The thermal analysis showed that the combined synthesis promotes more easily the crystallization of the TiO2 rutile phase. The composite obtained after heat treatment at 500 degrees C showed to be formed of almost only rutile phases of both oxides. The optical properties analyzed by UV-Vis spectroscopy showed that the combined oxides have higher absorbance, which reinforces a model found in the literature based on the flow of photo-generated electrons to the conduction band of SnO2 delaying the recombination of charges.

Composite resin susceptibility to red wine staining after water sorption

Color stability of restorative materials is essential for longevity of esthetic composite restoration over time. The aim of this investigation was assess the effect of prior water immersion on the color stability of a composite resin to red wine staining. Seventy disccshaped specimens (6mm x 1.5mm) were carried out and randomized in 7 groups (n = 10), according to distilled water immersion time at 0 (control), 24, 48, 72,120,192, and 240 h. Baseline color was measured according to the ciel*a*b* system using a reflection spectrophotometer(uvc2450, shimadzu).After that, the specimens were storage in red wine for 7 days. Color difference (∆e) after aging was calculated based on the color coordinates before(baseline) and after storage period.Data were subjected to onecway anova(alpha=0.05).The different times of immersion in.Water before to the red wine storage showed similar behavior on the color stability, without statistical difference compared to control group, immersed directly in the wine(p=0.7057).The previous water uptake of composite resin evaluated did not decrease the susceptibility to red wine staining.

Avaliação da termociclagem sobre a estabilidade de cor de diferentes matizes de resina composta

The objective was to evaluate the effect of thermocycling on the color variation of three different composite resins . We studied was Resin Enamel on 3 levels : ( Esthetic X , Opallis and Venus ) ; Resin Dentin in three levels : ( Esthetic X , Opallis and Venus ) and Thermocycling on level 1 : ( 3,000 cycles ) ; variable was the change of color gauged by spectrophotometry . 60 specimens , subdivided into 6 groups were made : GI - Esthetic X Enamel ; GII - Esthetic X dentin ; GIII - Opallis Enamel ; GIV - Opallis dentin ; GV - Enamel and GVI Venus - Venus dentin . The specimens were prepared with a matrix to standardize samples . The inserts of incrementally resins and polymerized with a halogen light Ultralux unit ( Dabi Atlante , Brazil ) with a power of 450mW / cm ² . After fabrication , underwent color reading with a UV Visible Spectrophotometer reflection , UV -2450 ( Shimadzu , Kyoto , Japan ) , with the changes calculated by the system CIE L * a * b * . Then isolates were stored in artificial saliva at 35 ° C ± 2 ° C during 3 months containers being subjected to the effects of thermal cycling for 3000 cycles over the range of 5C to 55C . Again subjected to chromatic evaluation. For the analysis of the results of color change of the studied resins was applied ANOVA two factors at 5 % . The results showed a statistically equal resins enamel GI and GV ( p = 0.79 ) ; the same was not observed for GI and G III resins , where the color change was higher for resin G III ( p = 0.0000002 ) . The same was observed between G III and GV , where the resin enamel G III showed a statistically superior to the color change ( p = 0.0000005 ) Average . Resins to dentin was there a statistical equality between the materials studied . We conclude that the resins studied change in color and resin enamel G III was the most suffered major color changes after aging by thermocycling .

Synthesis and characterization of nanostructured TiO2-SnO2 composite

Nanostructured composites based on titanium dioxide have been studied in order to improve optical and photo-catalytic properties, as well as their performance in gas sensors. In this work, titanium and tin dioxides were simultaneously synthesized by the polyol method resulting in TiO2 platelet coated with SnO2 nanoparticles as was observed by scanning electron microscopy. The thermal analysis showed that the combined synthesis promotes more easily the crystallization of the TiO2 rutile phase. The composite obtained after heat treatment at 500 °C showed to be formed of almost only rutile phases of both oxides. The optical properties analyzed by UV-Vis spectroscopy showed that the combined oxides have higher absorbance, which reinforces a model found in the literature based on the flow of photo-generated electrons to the conduction band of SnO2 delaying the recombination of charges.

Análise da efetividade de polimerização, adaptação marginal e interna de restaurações Classe II de resinas compostas de inserção em bloco utilizando diferentes matrizes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência de soluções de clorexidina e de própolis e da simulação de pressão pulpar na resistência de união dentinária

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da resistência de união de reparos em resinas compostas convencionais e bulkfill

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação imediata e após 6 meses da resistência de união a dentina de restaurações de resina composta classe I in vivo e in vitro

Pós-graduação em Odontologia Restauradora - ICT

Avaliação imediata e após 6 meses da resistência de união a dentina de restaurações de resina composta classe I in vivo e in vitro

Pós-graduação em Odontologia Restauradora - ICT

Particulate composite based on coconut fiber and castor oil polyurethane adhesive: An eco-efficient product

This paper presents a study on the potential use of coconut fiber as material to produce particleboards, with two different densities (0.8 g/cm(3) and 1.0 g/cm3), using castor oil-based polyurethane adhesive and urea-formaldehyde. The quality of the product that can be produced by industry was evaluated according to the normative NBR 14.810:2006, where density, thickness swell (TS), absorption, modulus of elasticity (MOE), modulus of rupture (MOR) in static bending and internal bond (IB) were determined. From the results, there was a decrease in TS and increase in MOR of coconut fiber panels with polyurethane resin panels compared with coconut fiber and resin urea-formaldehyde. Scanning microscopy electronic images (SEM) indicated that castor oil-based polyurethane adhesive occupies the gaps between the particles, a factor that contributes to improved physical and mechanical properties of the panels. The assessment of durability through accelerated aging tests shows that panels protected with waterproofing material can be used in environments that have contact with moisture. (C) 2012 Elsevier B.V. All rights reserved.

PHYSICO-CHEMICAL, SPECTROSCOPICAL AND THERMAL CHARACTERIZATION OF BIODIESEL OBTAINED BY ENZYMATIC ROUTE AS A TOOL TO SELECT THE MOST EFFICIENT IMMOBILIZED LIPASE

Two microbial lipases from Burkholderia cepacia and Pseudomonas fluorescens were evaluated as catalysts for the enzymatic transesterification of beef tallow with ethanol and the most efficient lipase source was selected by taking into account the properties of the product to be used as fuel. Both lipases were immobilized on an epoxy silica-polyvinyl alcohol composite by covalent immobilization and used to perform the reactions under the following operational conditions: beef tallow-to-ethanol molar ratio of 1:9, 45 degrees C and 400 units of enzymatic activity per gram of fat. Products, characterized using Fourier Transform Infrared spectroscopy (FTIR), viscosimetry, thermogravimetry and H-1 NMR spectroscopy, suggested that the biodiesel sample obtained in the reaction catalyzed by Burkholderia cepacia lipase has the best set of properties for fuel usage.