Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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2004 - 200932010 - 20111

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Access type: Open accessSubject: search.filters.subject.Borates

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Now showing 1 - 4 of 4
  • Master Thesis
    The Development of Synergistic Heat Stabilizers for Pvc From Zinc Borate-Zinc Phosphate
    (Izmir Institute of Technology, 2004) Erdoğdu, Cem Aykut; Balköse, Devrim
    Poly(vinyl chloride) (PVC), releases smoke and toxic gases (hydrogen chloride, HCl) during heating at temperatures above 140 C with the result of dehydrochlorination reaction. Obtaining flame retardant and smoke suppressed PVC compositions are getting more and more important. PVC is widely applied as a covering insulation for electrical and communication cables and in domestic uses such as window frames, doors, profiles, sidings and gutters because of its high level of combustion resistance.For this reason, many additives are studied to achieve better compositions than the present ones.In this study, the synergistic effects of zinc borate (ZB) . zinc phosphate (ZP) on thermal stability of plastigels obtained from PVC and dioctylphthalate (DOP) plastisols were investigated using spectroscopic and thermal techniques. Plastigels having a total of 2.5 parts (w/w) of zinc borate and zinc phosphate, 80 parts (w/w) of DOP and 100 parts (w/w) of PVC were gelled at 140 C for 15 minutes in a vacuum oven. The plastigel films having different compositions of ZB and ZP were investigated after heating at 140°C and 160 C from 15 minutes to 90 minutes by using Fourier Transform Infrared (FT-IR) spectroscopy, Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX). The kinetic studies were made by PVC Thermomat 763 instrument. HCl gas released due to heating of the plastigel films at both 140 C and 160°C in PVC Thermomat instrument under nitrogen gas increases the conductivity of deionized water in measuring vessels of this instrument. By measuring the conductivity change in water caused by the absorption of HCl released, the thermal degradation of PVC plastigel films were studied by means of reaction rates, rate constants and activation energies. Compositions having only ZB or ZP have retarded dehydrochlorination of PVC compared with the control sample. However, the compositions with both ZB and ZP have a superior synergistic effect on char formation of PVC. Since induction times of the compositions having both ZB and ZP were higher than that of the control samples having only ZB or only ZP, the synergistic effect was observed.The compositions greatly promote the char formation of PVC. The thermal stability of plastigels was also studied by their yellowness index (YI). The elemental compositions of these films were investigated in atomic scale using EDX and SEM and their compositions were calculated both for particles and matrix.
  • Master Thesis
    Oxo-Imido molybdenum tripyrazolyl borate complexes
    (Izmir Institute of Technology, 2004) Günyar, Alev; Topaloğlu Sözüer, Işıl
    Reaction of the oxo-molybdenum(V) compound, [MoTp*(O)Cl2], [Tp* = hydrotris(3,5-dimetylpyrazol-1-yl)borate] with p-functionalized anilines[NH2C6H4R] ( R = OMe, OEt, OPr, NO2) in the presence of Et3N under nitrogen, in toluene solution, afforded the novel oxo bridged oxo(arylimido) molybdenum(V) compounds [MoTp*(O)Cl](m-O)[MoTp*(Cl)(ºNC6H4R)] ( R = OMe, OEt, OPr, NO2). Under same conditions, the reaction with aniline produced oxo bridged oxomolybdenum (V) compound, [MoTp*OCl]2(m-O). The new compounds were characterized by FT-IR, FAB-Mass, and 1H-NMRspectra. The single crystal X-ray crystallographic determination of [MoTp*(O)Cl](mO)[MoTp*(Cl)(ºNC6H4OMe)]was carried out to confirm that there is a Mo-O-Mobridge and a near linear arylimido group in the structure.
  • Master Thesis
    Snythesis, Characterization of Borosilicate Nanoparticles and Investigation of Their Cytotoxicity and Genotoxicity in Human Cell Lines
    (Izmir Institute of Technology, 2011) Öztürk İlgü, Ekin; Özçelik, Serdar
    In this study, firstly, we aimed to synthesize silica and borosilicate nanoparticles by the Stöber method. We then investigated the biological response of bronchoalveolar carcinoma-derived cells (A549) and healthy bronchoalveolar cells (BEAS2B) against the silica and borosilicate nanoparticles, by evaluating cytotoxicity and genotoxicity. The nanoparticles were synthesized by a modified Stöber method. To prepare borosilicate nanoparticles tri methoxy boroxine (TMB) was used as boron source to coat the surface of the silica nanoparticles. By varying the amounts of ethanol and ammonia the size of nanoparticles were tuned from 60 to 450 nm. We proved the presence of boron in the borosilicate nanoparticles by Energy-Dispersive X-ray (EDX), Fourier Transformed Infrared (FTIR) spectroscopy and an acid-base titration method. Cytotoxicity and genotoxicity induced both silica and borosilicate nanoparticles were investigated for the cell lines of A549 and BEAS-2B. Silica and borosilicate nanoparticles in all three sizes and dosages up to 500 μg/mL did not induce cytotoxic effects in A549 cells with incubation time up to 72 hours. The same amount of particles did not result in any cytotoxicity in BEAS-2B cells for 24 hours incubation, but they showed cytotoxic effects when the incubation time was increased to 48 and 72 hours. Furthermore, nanoparticles with sizes of 60 and 100 nm showed no genotoxicity for A549 but for BEAS-2B cells, silica nanoparticles induced genotoxic effects contrary to borosilicate nanoparticles.
  • Master Thesis
    The Development of Zinc Borate Production Process
    (Izmir Institute of Technology, 2004) Eltepe, Hüdal Emre; Balköse, Devrim; Balköse, Devrim
    The main objective of this study is the production of zinc borate which is used in large quantities as flame retardent and smoke subpressent material by making use of ourcountry.s resources which is the largest boron reserves in the world. The development of commercially acceptable zinc borate production process was investigated from several different views and the samples obtained were characterized by using different techniques. The physico-chemical properties of each sample were characterized by X-Ray diffraction, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) analysis, thermal gravimetric analysis (TGA). Several forms of zinc borate with various dehydration temperatures are possible to obtain.A popular form of zinc borate which dehydrates above 290 C was obtained in this study.