Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Assessment of Lighting Performance of Pvc and Pmma Materials in Office Spaces in Terms of Visual Comfort(Izmir Institute of Technology, 2006) Öztürk, Müge; Ergül, EmreThis research tests the plastic materials which can provide properly diffused illumination level and have smooth transmittance performance. Among these materials, two of them, PVC (polyvinylchloride) and PMMA (polymethylmethacrylate) sheets are evaluated, compared with each other and application possibilities. Besides, one of most important evaluation criteria for efficient lighting in office spaces; transmission property of these materials is empirically tested in laboratory in the scope of this study. One of these, PMMA is produced on commercial purpose in Turkey and used with its well known name; Plexiglas and the other one; Barrisol is an officially registered trademark of PVC translucent strech sample used in test. This study is gathered by means of searching lighting literature, rather restricting the data about two specific plastic based materials used in offices and experimenting the transmission characteristics of plexiglas and Barrisol. Scientifically; transmitting and diffusing of a material are unattached properties and rather concerned with chemistry. But there is a measured certainity that Plexiglas has %92 and Barrisol %73 percentage of transmission value. The results of test also supports that; transmission percentage of plexiglas sample is higher than Barrisol. It is reached to the conclusion that; when light directly comes down on a workplane whithout being regularly dispersed, it will tire viewer.s eyes and deteriorate visual comfort, negatively affecting productivity in offices.Master Thesis The Development of Synergistic Heat Stabilizers for Pvc From Zinc Borate-Zinc Phosphate(Izmir Institute of Technology, 2004) Erdoğdu, Cem Aykut; Balköse, DevrimPoly(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 Use of Fly Ash as an Alternative Filler Material in Pvc-Pastisols(Izmir Institute of Technology, 2010) Sayhan, İpek; Polat, HürriyetIn this study, an alternative filling material, fly ash was tested in PVC pastisols. Therefore, - 38 .m Soma fly ash sample was used and its results were compared with that of calcite material as a filler. Therefore, this study was conducted to have three sections as: 1) Characterization of powders calcite, fly ash and PVC powder: SEM, XRF, XRD, Size measurement, 2) Preparation and characterization of PVC plastisols with and without fly ash: Rheological measurements 3) Characterization of final PVC product: Surface, hardness and strength tests. The results of fly ash were always compared with the results of calcite and discussed in this thesis. It was suggested that fly ash could be an alternative filling material for PVC plastisols. It.s effect, on the other hand, was found to change depending on the temperature, mixing speed and concentration. In overall, the mechanical properties of PVC-product obtained were affected positively and better PVC materials were obtained. Under some conditions, however, the rheological properties were became shear thickening while it was newtonian and shear thining before. The changes in the rheological properties of PVC plastisols and the mechanical properties (quality) of final PVC-product were all explained by the differences in the composition and shape of the fly ash particles. Because, the composition and shape of the particles are expected to affect the interactions of PVC particles with that of filler material which will definetely affect the quality of material.