Browsing by Subject "Polimer Bilimi"

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    Synergistic effect of h-BN on thermal conductivity of polymer composites
    (2022) Nilay Kucukdogan
    The conductivity characteristics of polymers and polymer composites have become more significant recently. Good heat dissipation is required in many applications, such as circuit boards and heat exchangers, so it is essential to develop the thermal conductivity characteristics of the materials. The micro-fillers have been replaced with nano or hybrid fillers to increase the low thermal conductivity of the polymer. Hexagonal boron nitride (h-BN) and multi-walled carbon nanotubes (MW-CNT), both of which have good conductivity properties, are two popular filling materials. The presence of hydroxyl and amino active groups at the corners of the hexagonal structure of BN improves the thermal conductivity properties of the polymer composite. In addition, it shows high thermal conductivity behavior in polymer composite structures with BN and MW-CNT. It is essential to demonstrate the effects of the volume fraction of additives on the thermal properties of composites with various approaches. In this study, the thermal conductivity behaviors of h-BN/high-density polyethylene and h-BN/MW-CNT/high-density polyethylene composites are demonstrated using the theoretical Bruggeman model, which is based on the assumption that there are constant infinitesimal changes in the material so that there is an interaction between particles. The coefficient of determination (R²) between the thermal conductivity values of the composites and the predictions of the Bruggeman theoretical model is greater than 0.98. This way, the synergetic effect of h-BN and MW-CNT/h-BN additives on thermal conductivity has been theoretically proven.
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    Preparation and Performance Testing of SBS Modified\rBitumens Reinforced with Halloysite and Sepiolite\rNanoclays
    (2022) Dilay Uncu; Ali Topal; M.Ozgur Seydibeyoglu
    In this study, halloysite and sepiolite nanoclays were used to reinforce SBS modified\rbitumens. The nanoclays used are different from the materials in the literature and have\rproperties such as easy to find, economical and available from local sources. The mixing\rparameters were determined before production process. The polymer additive SBS was\radded into base bitumen at 3% and 5%, while the nanoclay additives were added into polymer\rmodified bitumen at 2% and 4% ratios. The morphological structures were investigated under\rfluorescence microscope. Physical and rheological properties of the samples were compared.\rThe phase separation cases were investigated by storage stability test. Furthermore, rutting\rperformance of samples was measured with zero shear viscosity (ZSV) and multi stress creep\rrecovery (MSCR) test methods.