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25. Study of Piezoelectric Filler on the Properties of PZT-PVDF Composites.

Author

Matei, Alina, Țucureanu, Vasilica, Vlăzan, Paulina, Cernica, Ileana, Popescu, Marian, and Romanițan, Cosmin

Subjects
LEAD zirconate titanate, PIEZOELECTRIC composites, POLYMERIC composites, COMPOSITE materials, CRYSTAL structure
Abstract

The ability to obtain composites with desired functionalities is based on advanced knowledge of the processes synthesis and of the structure of piezoceramic materials, as well the incorporation of different fillers in selected polymer matrix. Polyvinylidene fluoride (PVDF) is a fluorinated polymer with excellent mechanical and electric properties, which it was chosen as matrix due to their applications in a wide range of industrial fields [1-4]. The present paper focuses on the development of composites based on PZT particles as filler obtained by conventional methods and PVDF as polymer matrix. The synthesis of PVDF-PZT composites was obtained by dispersing the ceramic powders in a solution of PVDF in N-methyl-pyrrolidone (NMP) under mechanical mixing and ultrasonication, until a homogenous mixture is obtained. The properties of the piezoceramic fillers before and after embedding into the polymeric matrix were investigated by Fourier transform infrared spectrometry, field emission scanning electron microscopy and X-ray diffraction. In the FTIR spectra, appear a large number of absorption bands which are exclusive of the phases from PVDF matrix confirming the total embedding of PZT filler into matrix. Also, the XRD pattern of the composites has confirmed the presence of crystalline phases of PVDF and the ceramic phase of PZT. The SEM results showed a good distribution of fillers in the matrix. [ABSTRACT FROM AUTHOR]

Published
2017
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26. EXPERIMENTAL ASPECTS FOR CeO2 NANOPARTICLES SYNTHESIS AND CHARACTERIZATION.

Author

MATEI, Alina, ŢUCUREANU, Vasilica, ŢÎNCU, Bianca Cătălina, POPESCU, Marian, ROMANIȚAN, Cosmin, CERNICA, Ileana, and DUMITRESCU, Lucia Georgeta

Subjects
CERIUM oxides, NANOPARTICLE synthesis, HEAT treatment, X-ray diffraction, SCANNING electron microscopy
Abstract

In recent years, cerium oxide (CeO2, or ceria) became a versatile nanostructured material because of its unique properties derived from the low dimensionality and high surface area. It was also extensively studied due to its practical performances in many scientific and industrial applications, such as fuel cells, luminescent materials, gas sensors, insulators, white LEDs, etc. In this paper, the research focused on the synthesis and characterization of cerium oxide powder manufactured by the co-precipitation method, using inorganic cerium salt (Ce(NO3)3) and the precipitating agent (NaOH). In order to optimize the CeO2 particles synthesis process, the parameters of the process were monitored to obtain the quantitative precipitate and to optimize the heat treatment. The precursors type and concentration used, reaction temperature and time, the pH of reaction medium and order of the precipitating agent addition are the main factors influencing the particle size and morphology of cerium oxide nanoparticles. The physico-chemical properties of the cerium oxide nanoparticles were determined by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX). The FTIR spectrum of the CeO2 particles calcinated at 550 °C, in normal atmosphere, exhibits a strong band at 482 cm-1 corresponding to Ce-O stretching vibration. The XRD pattern confirmed the crystalline nature of the CeO2 nanoparticles with a cubic structure and average crystallite size around 15 nm. Moreover, EDX analysis confirms the presence of the Ce and O atoms corresponding to the theoretical formula. The morphology and microstructure were studied using SEM analysis. [ABSTRACT FROM AUTHOR]

Published
2017

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