ABSTRACT Centrifugal spinning is a new technique for producing of nano and microfibers that has a great differential: a higher production rate than those presented by traditional methods. Due to a great interest in using nano and microfibers in technological applications along with the environmental interest in polymer recycling, this research had the purpose of production fibers by centrifugal spinning from the expanded poly-styrene recycling and the evaluation of the influence of operational parameters such as the concentration of polymer solution and the speed of rotation in the average diameter and in the distribution of the diameters of fibers formed. The fibers obtained were characterized using the Scanning Electronic Microscopy (SEM) and they had their diameters measured using ImageJ software. The fibers obtained in this research were entangled, woven, fused, with a rough and porous surface, with bead formation and without directional ordering. The results obtained show that the polymer solution concentration was the most influential parameter in the fibers analyzed characteristics and, in general, its increase generates an increase in the average diameter. With the increase in rotation speed, there has been often a reduction in the presence of beads and microparticles due to the better stretching of the fibers. In less concentrated solutions, continuous fibers with more regular surfaces were obtained, however, promoting the higher production of beads. In the most concentrated solutions, we noticed the formation of porous fibers and very rough surfaces, as well as fused and woven fibers. Through the measurement of its diameters, it was possible to observe the obtaining of fibers with average diameters of 407,02 nm to 38113,20 nm, and the smallest value was obtained with the parameters of 5% w/w of polymer concentration and rotation speed of 15000 rpm and the highest value had 15% w/w concentration polymer and 10000 rpm.

Abstract This study developed and characterized a method for controlled deposition of thin films of hydroxyapatite on titanium surfaces. Thirty-three titanium cylinders were randomly divided: negative control/polished (A), acid etched (B) and coated by hydroxyapatite (C). Acid etch was performed in an aqueous solution of nitric acid. The cylinders were subjected to coating by a thin film of hydroxyapatite with dip-coating method. These cylinders were submitted to a pre-heat treatment 450°C/10 minutes and 800°C/2 hours. Scanning electron microscopy analysis demonstrated a homogeneous and smooth surface (A), an irregular and porous surface (B) and a crystalline deposition (C). The X-ray energy dispersive analysis showed characteristic elements of hydroxyapatite (C). Analysis by X-ray diffraction showed the presence of characteristic peaks of hydroxyapatite, corresponding to the structural composition of hydroxyapatite. Cell viability (MTT-assay in NIH-3T3-Cells) test demonstrated no differences between the groups. Titanium surfaces coated with a hydroxyapatite film by the dip-coating method suggest adequate control of deposition of thin films of hydroxyapatite and similar cell viability using mouse fibroblasts.

Abstract The nano/microstructures with highly porous surface area have attracted tremendous attention, particularly the synthesis and tailoring of porous and hollow materials of high performance. In this paper, an easy method of cost-effective synthesis of hollow ceramic fiber membranes based on Hydroxyapatite, TiO2 and ZrO2 stabilized with Yttrium, is proposed by a single chemical route (polymeric precursor method) and a bio-template route (easy to degrade in thermal conditions). This article reports also the ZrTiO4 nanowires synthesis on a silicon (100) wafer in a single step deposition/thermal treatment. Template-directed membrane synthesis strategy was associated to the polymeric precursor route and spin-coating deposition technique. In this method, ZrTiO4 nanowire ceramic were synthesized by spin-coating thermal treatment technique using polycarbonate membrane as a template. According to the results, after heat-treatment by the template removal, the ZrTiO4 nanowire consists of uniformly deposited crystalline and porous nanoparticles that exhibited a higher surface area and a higher porosity. The polycrystalline nanowires were obtained at by thermal treatment with diameter in the range of 60-100 nm. Photoluminescence spectra were collected for fiber at room temperature. These characterizations demonstrate the morphology of structures formed, showing its hollow and porous conformation, suitable applications to advanced reinforced or device component material.