Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2019
Student: ŞEYDA GETİR
Supervisor: HABİBE CANAN CABBAR
Abstract:In this study, it is aimed to synthesize monolithic silica aerogels by using sol-gel technique. As a source of silica in the study; Tetramethyl ortosilicate (TMOS) was used. Sample formed into sol is gelled in the syringe and the samples are removed from the syringe in the aging and drying step. After heat treatment (550 oC) monolithic cylindrical (opaque-transparent) structure was obtained in 1 cm diameter and 4 cm long. Studies performed on different amount of acetic acid (2-4 ml) and concentration (0,05-0,1 M) that uses as catalyst in sol formingstep. It was observed that as the acid amounts increased, the surface area decreased. It was determined that the concentration of ammonium hydroxide used during aging has an effect on the surface area of monolithic silica aerogel. Other parameters investigated are gelling, aging and drying temperatures. When the gelling temperature (30-60 oC) and the aging temperature (70-85 oC) were changed, the change in monolithic silica aerogel surface area and average pore diameter values were determined. As the gelling and aging temperatures increased, monolithic silica aerogel structure was observed to be more transparent and brittle. The surface area decreased as the drying temperature (40-100 oC) increased. Finally studies performed in different TMOS/(Polyethylene glycol) PEG ratio. The surface area decreases, when TMOS/PEG ratio increases. The Fourier infrared spectroscopy (FTIR) analysis of the samples produced by bond structures, Thermal gravimetric analysis (TGA) results were investigated with thermal durability. It was confirmed porosity and monolithic of the structure by Scanning electron microscope (SEM) analysis. Science