Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
Browse
2 results
Search Results
Master Thesis Piezocatalytic and Piezoelectric Properties of P(vdf) and Its Copolymer/Terpolymer Films(01. Izmir Institute of Technology, 2023) Tengizdeniz, Ceren; Adem, Umut; Genç, AzizNowadays, the release of colored organic pollutants such as Rhodamin B dye, resulting from industrial activities endanger the people, animals, and plants. Many methods have developed to destroy these harmful pollutants. Piezocatalysis, a newly used environmentally friendly method, takes advantage of the piezoelectric effect, and uses mechanical vibration to produce active species on opposite surfaces of matter for degradation of dye. In this study, piezocatalytic and piezoelectric properties of P(VDF) based homopolymer, copolymer and terpolymers were investigated. With the addition of 2nd and 3rd monomer to the homopolymer, observation of change in piezoelectric and piezocatalytic properties and removal efficiency of pollution in water, were aimed. P(VDF) homopolymer, P(VDF-TrFE) copolymers with composition of 55/45 and 50/50 mol%, and P(VDF-TrFE-CTFE) terpolymer with 62/31/7 mol% were synthesized by solution casting method. It was observed that the 2nd and 3rd monomer added to the homopolymer enhanced the piezoelectric properties and strain characteristics of the polymers. Maximum polarization and strain of terpolymer was observed as 11 µC/cm2 and 5.6 %, respectively. Due to the increase in piezoelectricity, a noticeable increase in piezocatalytic properties was observed. Terpolymer exhibited the highest and most efficient piezoelectric and piezocatalytic performance. P(VDF) homopolymer was reached 27% dye degradation efficiency. While copolymers with mol% 55/45 and 50/50, dye degradation efficiencies were 40% and 47%, respectively, terpolymer efficiency was 54%. From the dielectric measurements, within the transition region (49 mol% ≤ CVDF ≤ 55 mol%) of P(VDF-TrFE), both normal-ferroelectric and relaxor characteristics were observed. Terpolymer showed relaxor properties as expected.Master Thesis Formation of Srtio3[tio2] Ceramic Composites at Low Temperatures(01. Izmir Institute of Technology, 2021) Karataş, Esin; Adem, Umut; Ahmetoğlu, Çekdar VakıfStrontium titanate ceramics are materials belonging to the perovskite material group with the formula ABO3. Strontium titanate ceramics have been a preferred material in many areas, such as the electroceramics industry, due to its high dielectric constant and high chemical stability and generally produced by manufacturing processes such as solid-state synthesis, hydrothermal method, and sol-gel. SrTiO3 ceramics have been produced in the literature with different temperatures, times, and starting materials. For ceramic products, a sintering step is required after the powder production step. Traditional sintering methods, which have been used for many years, are used to densify powders with high temperatures. Recently developed low-temperature densification methods enable the sintering process to be carried out at relatively lower temperatures. For this purpose, in this thesis, SrTiO3-TiO2 ceramic composites were produced at different reaction temperatures and times using the rHLPD method, which combines powder production and sintering steps in a single process. In the studies, the reaction temperature, time, and the effect of adding mineralizer to the prepared solution for the hydrothermal reaction on the final product were investigated. The aim of the thesis is to produce SrTiO3 from TiO2 green body using the rHLPD method. In addition, the production of SrTiO3-TiO2 ceramic composites with as high mole conversion and relative density values as possible was targeted with different parameters such as reaction temperature, reaction time, and addition of NaOH to the solution. As a result of the studies carried out with different parameters, SrTiO3-TiO2 ceramic composites with a final relative density value of approximately 81 % were produced. Consequently, in the XRD and Rietveld analysis, it was seen that the main phase was SrTiO3. In addition, there was a TiO2 phase in the structure. Finally, the SrCO3 phase was not detected in the structure.