In this paper we aim to perform a cross section morphological characterization of an acrylic polymer used for dental prostheses subjected to microwave disinfection. The method was largely investigated and the microbiological effectiveness is well established, but there are some issues regarding the in-depth alteration of the material. In our research, the surface roughness is insignificant and the samples were not polished or refined by any means. Two groups of 7 acrylic discs (20 mm diameter, 2 mm thickness) were prepared from a heat-cured powder. Half of the samples embedded a stainless steel reinforcement, in order to observe the changes at the interfaces between the polymer and metallic wire. After the gradual wet microwave treatment, the specimens - including the controls - were frozen in liquid nitrogen and broken into pieces. Fragments were selected for gold metallization to ensure a good contrast for SEM imaging. We examined the samples in cross section employing a high resolution SEM. We have observed the alterations occurred at the surface of the acrylic sample and at the interface with the metallic wire along with the increase of the power and exposure time. The bond configuration of acrylate samples was analysed by FTIR spectrometry.
Semiconductor oxides such as SnO<sub>2</sub>, TiO<sub>2</sub>, WO<sub>3</sub>, ZnO<sub>2</sub> etc. have been shown to be useful as gas sensor materials for monitoring various pollutant gases like H<sub>2</sub>S, NO<sub>x</sub>, NH<sub>3</sub> etc. In this work, we would like to present the preparation of titanium dioxide films for gas sensor application, via the sol-gel technique. The coating solution was prepared by using titanium isopropoxide precursor, which was hydrolyzed with distilled water under the catalytic effect of different acids (HNO<sub>3</sub>, HCl or CH<sub>3</sub>COOH). Titanium dioxide films have been deposited using spin coating method and then synthesized at different temperatures. Fourier transform infrared spectroscopy observation has been used to analyze the sol-gel process. The morphology and the structure of the thin films were analyzed.
Interaction between polymers and nanoparticles are known to influence structure and properties of polymer materials containing dispersed nanomaterials. Titanium oxide was prepared by sol-gel method and used as inorganic materials; polyvinyl alcohol was used as polymer matrix. The objectives of this paper are to synthesize and characterized TiO<sub>2</sub> - polymer composite. TiO<sub>2</sub> nanoparticles were dispersed in polymer solution with the aid of ultrasonic vibration to obtained polymer composite materials.
The properties of TiO<sub>2</sub> - polymer composite films were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and optical microscopy. FT-IR showed that there existed a strong interaction at the interface of TiO<sub>2</sub> and polymer, which implied that the polymer chains were grafted onto the surface of TiO<sub>2</sub> nanoparticles. It can be also be seen from SEM images that the TiO<sub>2</sub> nanoparticles were perfect dispersed in polymer matrix.
Future electric lights will be composed of white LEDs (Light Emitting Diodes) and for this reason the development of
new luminescence materials has become a great challenge to researchers. In the present paper it is presented a sol-gel
method, simple and with superior potential for synthesis of nanoparticles of yttrimn aluminium garnet doped with
cerium luminescent powders. This method has a big potential for application in new generation luminescent lighting
devices. The gels were prepared using stoichiometric amounts of reagent-grade Y<sub>2</sub>0<sub>3</sub> and A1<sub>2</sub>0<sub>3</sub> as the starting
materials. The XRD pattern of the powder calcinated al 1100°C shows the formation of single-phase nano-crystal garnet
materials. The XRD measurements and AFM measurements show that we obtained a phosphorus with grain size of 24
nm. The emission spectra of white LED demonstrate that acquired phosphor has good applicability in optoelectronics.