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    Öğe
    Microencapsulation of n-tridecane / n-tetradecane eutectic mixture with poly(methyl methacrylate) shell for candidate for food packaging thermal energy storage material
    (Taylor & Francis Inc, 2023) Ertugral, Tuba Gungor; Danisman, Merve; Oral, Ayhan
    Among the healthiest methods of food preservation is cold storage, but expensive, non-eco-friendly fossil fuel-based materials are used for this purpose. Microcapsules that do not store latent heat at phase change can be applied to packaging material with their heat storage and diffusion properties to minimize the use of fossil fuels. This application with such features as light weight and small footprint can reduce transportation and storage costs. In the food industry, one of the sensitive products with a storage temperature of 0-2 degrees C is food and especially aquatic products. The packaging materials (styrofoam, plastic crate, etc.) are ineffective in maintaining the temperature required for the storage and transportation of food products. Moreover, during transportation, the ice in Styrofoam sticks together because of temperature fluctuations and forms a mass that is heavy enough to crush the product. Microcapsules containing phase change material (PCM) keep products at a reasonable storage temperature in the case of undesired temperature rises or drops. This study uses polymethylmethacrylate (PMMA) microcapsules containing n-tridecane (C13) and n-tetradecane (C14), with cooling properties to prevent temperature fluctuations. The microcapsules were characterized by thermogravimetric analyzer (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), polarized optical microscope (POM), and a particle size analyzer. The DSC results showed that PMMA/(C13-C14) microcapsules can store 89.63 J/g latent heat energy at (+0.30)-(+2.80 degrees C), which is within the targeted temperature range. In addition, the research produced microcapsules usable for food that can be stored at (-9) to (-3) degrees C.
  • [ X ]
    Öğe
    Surface modification of hydroxyapatite with enzyme-catalyzed reaction: Computation-supported experimental studies
    (Elsevier Science Sa, 2022) Danisman, Merve; Berisha, Avni; Dagdag, Omar; Oral, Ayhan
    Surface modification of the selected particles for different uses (chemical, biological or commercial applications) is a frequently adopted method for industrial and scientific purposes. Thus, the molecules determined for the targeted applications can be attached to particles. However, these methods occur in several steps, at high temperatures, and for long periods of time and require the involvement of chemicals. Chemicals used in the environment and under harsh conditions lead to some restrictions (such as monomer variety and application areas) and cause energy and time loss. Presumably, these problems could be largely avoided by using enzymes, which are natural biocatalysts, in the surface modification of particles. Given this presumption, a surface modification design was devised in this study to modify the hydroxyapatite surface with methacrylic acid using the lipase enzyme. The chemical structures of the particles were characterized through Fourier Transform Infrared and Raman spectroscopy, their thermal behaviors were analyzed with thermogravimetric analysis, and simultaneous molecular modeling studies were conducted to corroborate the experimental studies.