LEE- Kimya Mühendisliği-Yüksek Lisans

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http://hdl.handle.net/11527/19355

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Konu "alternative filling materials" ile LEE- Kimya Mühendisliği-Yüksek Lisans'a göz atma
  • Öge
    Effect of alternative filling materials on tire compounds
    (Graduate School, 2023-01-19) Çetindağ, Nazlı Kezban ; Taygun Erol, Melek Mümine ; 506191042 ; Chemical Engineering
    The tire, one of the most important parts of the vehicle, is a composite material consisting of many components and many raw materials. Tire production consists of different stages. One of these stages is mixing and compound preparation. At this stage, different raw materials are mixed homogeneously in the equipment called mixer in order to obtain the desired mixing properties. This mixing process consists of multiple steps. The most common raw materials are rubbers, filling materials, oils, antioxidants and curing agents. Considering the raw materials, rubbers and filling materials constitute the largest part of the compound. Looking at the rubber part, rubbers with different properties such as natural rubber, styrene butyl rubber, butyl rubber, chloro-butyl rubber are used. While these rubbers are sometimes used alone, sometimes they are used as combinations of different rubbers. Filling materials consist of very different materials such as carbon black, silica, calcium carbonate. The most widely used filling material is carbon black, and its main purpose is to provide reinforcing to rubber. At the same time, the reason why the tire is black is due to the color given by the carbon black. In addition, filling materials such as silica are used to give the compound low rolling resistance, while raw materials such as calcium carbonate are used to reduce the raw material cost of the tire. Along with these, many studies have been investigating alternative filling materials to reduce the cost of tire compound. In this study, it was aimed to reduce the cost of tire compound. Also, it was paid attention to contribute to the circular economy when choosing those materials. Therefore, charcoal dust and fly ash, which are classified as waste materials, were chosen in this study. Coal has low sulfur and mercury content compared to fossil fuels. It also contains less nitrogen and ash. Fly ash, on the other hand, is a by-product of thermal power plants and this material is classified as waste. Therefore, many studies have been searching for alternative ways to use this material. The charcoal used in this study was obtained from oak wood. Fly ash was taken from Çatalağzı thermal power plant. Before using charcoal in recipes, the particle size was reduced by pre-treatment. Then, particle size analysis, thermogravimetric analysis and x-ray diffraction analysis were applied. Particle size and x-ray diffraction analyzes were applied to the fly ash. While applying the particle size analysis, the particle size of the carbon black together with the charcoal and fly ash was also examined. While applying thermogravimetric analysis to charcoal, the results were compared with carbon black. In this study, the effects of charcoal and fly ash in 3 different recipes were analyzed using different amounts. The most basic difference of the recipes used was the type of the rubber. The reference recipes were chosen as natural rubber, styrene butyl rubber and chloro-butyl rubber. At the same time, control compounds without the addition of alternative filling materials were prepared to compare the results of all experiments with the reference recipe. 9 different experiment versions were prepared with the reference recipe containing natural rubber and the results were compared with the control compound. In these versions, charcoal and fly ash were used separately. However, it was used at different amounts as 1 phr, 2.5 phr, 5 phr and 10 phr. At the same time, in one of the versions, charcoal and fly ash were used in equivalent amounts in the recipe, 5 phr each. Moreover, in the reference recipe containing styrene butyl rubber, the control compound was compared with 4 different trial versions. Two of these versions used charcoal at 5 phr and 10 phr, respectively, while the other two used the same amounts of fly ash. In the reference recipe containing chloro-butyl, as in the recipe using styrene butyl rubber, 4 different experiment versions were prepared and the effect of charcoal and fly ash on this recipe was examined, as in other recipes. Mooney, MDR, stress-strain test and x-ray diffraction tests were applied to the obtained samples. The mooney test shows the uncuring properties of the compounds, while the other tests show the curing properties. Viscosities of the samples were analyzed with the mooney test, and the effect of processability was investigated. The ideal curing conditions of the samples were determined by the MDR results. Stress-strain test was applied under four different conditions. While different reference recipes gave different viscosity results, addition of charcoal and fly ash to the recipes did not significantly change the viscosity results. Likewise, while the curing curves of different reference recipes showed different results, the addition of charcoal and fly ash did not change significantly the curing characteristics of the samples. Therefore, experiments with the same reference recipe were prepared under the same curing conditions for the stress-strain test. In the stress-strain test, the modulus at 300% elongation and the tensile strength and elongation at break were measured. While the results that would affect the use in modulus could not be obtained, the results in tensile and elongation were not promising in use. When the effects of charcoal and fly ash were compared with each other, it was observed that charcoal showed worse results than fly ash. This was thought to be due to the cellulosic structures and larger particle sizes in charcoal. When the tensile strength at break of the samples tested at room temperature was examined, it showed the worst result in the use of charcoal in the recipe with natural rubber, while it showed the best result in the recipe containing chloro-butyl. When looking at the use of fly ash, there was no obvious difference in recipes containing natural rubber and chloro-butyl, while the results in recipes using styrene butyl rubber were relatively better. On the other hand, when the elongation at break of the samples tested at room temperature was examined, the best results were observed in both charcoal and fly ash in the recipe using styrene butyl rubber, while the worst results were seen in the recipe containing chloro-butyl. The control compounds that serve as the reference compounds, had the greatest ZnS and ZnO peaks in x-ray diffiraction. In contrast to the charcoal's composition, which showed SiO2 and FeS peaks, the fly ash's composition showed mullite and gehlenite. The compositions in both charcoal and fly ash were not observed, though, when the versions of the experiments with these additions were evaluated. This may be due to the control compounds had much more ZnS and ZnO content which shaded the crystalline structures of the fly ash and charcoal since their amounts were so low. The fly ash particles were spherical, according to the SEM study, whereas the charcoal particles were angular and irregularly formed. Although these effects were not visible when looking at the samples from the surface, they were visible when looking at the samples from the cross-sectional region. SEM observations showed that the addition of both charcoal and the fly ash to recipes were successful. As a result, more studies are needed to use the charcoal and fly ash used in this study as tire compounds. Further grinding systems can be used to reduce the particle size. But then, since these alternative materials do not show any problem in processability, their use in non-tire products that do not require high performance can be investigated.