Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Hydrothermal Synthesis and Characterization of Tungsten Oxide Containing Organic-Inorganic Hybrid Material(Izmir Institute of Technology, 2019) Chilufya, Langson; Emirdağ Eanes, Mehtap; Eanes, MehtapImportance and a wide area of applications of solid-state oxides are well known. Metal oxides crystallize in wide variety but simple structures. Lately general opinion is that piezoelectric, ferromagnetic and catalytic properties of simple oxide structures will be improved if the metal oxides could have more complicated and detailed crystal structures. Therefore, research interest increased towards synthesizing complicated crystal structures. One of the methods to increase the complexity of the structure is the modification of inorganic oxides with organic ligands to synthesize complex hybrid materials. There are a great number of organic-inorganic hybrid materials with Keggin or Lindqvist Polyoxometalates structure containing Molybdenum and Tungsten. Usually Obtaining multifunctional hybrid materials, mostly requires grafting an organic functionalized group into the lacunary Keggin structures [XM11O39](n+4)-. Only Tungsten containing polyoxometalates can form a stable lacunary Keggin structures. A Lindqvist structures [M6O19]2- can also self-assemble with organic dyes to form a stable hybrid materials which have important applications. These polyoxotungstates, as an inorganic building blocks, were combined with organic compounds to obtain organic-inorganic hybrid materials. The carboxylic acid functionalized organotin grafted lacunary Keggin structure was coupled with different amines using N, N’-dicyclohexylcarbodiimide (DCC). Another hybrid material was formed by the association of the Lindqvist POM with phosphine based BODIPY derivative dye. The synthesized compounds were all characterized by SEM, FT-IR, TGA and Powder XRD. Since one of the organic moiety use was a BODIPY-type organic dye, the fluorescence properties of these newly synthesized compounds were investigated.Master Thesis Tribological Behaviour of Polymer Nanocomposities Containing Tungsten Based Nanoparticles(Izmir Institute of Technology, 2007) Karal, Kazım; Tanoğlu, MetinThe use of nanostructured fillers in epoxy systems has a significant role on the development of thermosetting composites. Recent investigations on inorganic nanoparticles filled polymer composites reveal their significant potential in producing materials with low friction and/or high wear resistance. In the present study, epoxy nanocomposites and fiber reinforced polymer (FRP) composites were prepared with the addition of tungsten based nanostructured particles which are produced by mechanical alloying. The effects of the nanostructured additives on the tribological, mechanical and thermal properties of composite laminates and nanocomposites were investigated. Composite laminates with and without filler were manufactured by using hand lay-up technique and cured under compression. It was found that tungsten based particle loading has no significant effect on the flexural properties of the nanocomposites and the composite laminates, and the tensile properties of the nanocomposites. It was found that while the addition of 3 wt. % of nanoparticles increases the hardness values, it significantly improves the wear resistance of nanocomposites. Furthermore, the significant improvement on the wear resistance was observed with the addition of 3 wt. % W-SiC-C (24h mechanical milling) powder onto the surface of fiber reinforced epoxy. The worn surfaces were examined with scanning electron microscopy (SEM) and the results revealed that wear mechanisms are altered due to the presence of nanoparticles in the matrix. Differential scanning calorimetry (DSC) results showed that nanoparticles have no significant effect on glass transition temperatures (Tg) of nanocomposites. Incorporation of nanoparticles increased the thermo mechanical properties of nanocomposites and composite laminates; including the storage and loss modulus and Tg.