| Summary: | 碩士 === 國立臺北科技大學 === 材料及資源工程系所 === 93 === Geopolymer, an inorganic polymer, has been gradually attracting world attention as potentially innovative materials due to their great physical/mechanical properties. Three basic sources are needed for geopolymer synthesis, i.e. raw materials, active filler, and alkaline liquor. Many studies have used the metalaolinite as main supporting Al ion material, and most of these metakaolinite were produced by calcining kaolinite at the temperature of 750℃ for several hours. Little work has been undertaken to determine the properties of geopolymers on the relationship between different temperatures sintered metakaolinite. The current research work is fundamentally investigated the effect of various temperatures sintered metakaolinite on the properties of geopolymers. Metakaolinites by different temperature sintered were measured by DTA, XRD and BET. It is interesting to found from DTA results that the maximum mass loss of dehydration of kaolinite occurs at the sintering temperature of 650℃ and reached to 11wt%. The compressive strength of the geopolymer manufactured by using 650℃ sintered metakaolinite also obtained the best strength result.
After fabricating geopolymer for few weeks, it sometimes can be found white materials on the surface of geopolymer. From XRD results, this surface salt is trona that was found due to excess of K or Na ions reacted with CO2 from the atmosphere. Alkali titration tests were carried out to measure hydroxide, carbonate and bicarbonate in various geopolymers in order to understand that the interrelationship between different temperatures sintered metakaolinite and mechanical properties. Experimental results show that the amount of hydroxide in geopolymer decreased with increasing curing days and kaolinite sintering temperature. The higher the compressive strength of the geopolymer, the less of the hydroxide contains in the geopolymer. Carbonate contents are increasing while kaolinite sintered at lower temperatures and short heat treatment times. It is also interesting to found that the quantity of bicarbonate will decrease when the geopolymer compressive strength increase. This could because geopolymers have better structures, therefore, lower content of the residues of K and Na ions on the surface to produce bicarbonate.
|
|---|
