• MakaleYayıncıda açık erişim2024Scopus SJRQ2
    Selenium Inhibitor Coating on NiTi Shape Memory Alloys by Using Thermal Evaporation System

    Kök, Mediha; Kanca, Muhammed Sait; Say, Yakup; Saydam, Sinan; Dağdelen, Fethi; Qader, Ibrahim Nazem

    NiTi-based memory alloys are often used as intracorporeal implant materials because of their superelasticity and shape memory properties. However, over time, the release of nickel from the NiTi alloy into the body becomes unfavorable; therefore, studies should be conducted to reduce the negative impact of nickel leakage. In this study, the biocompatible selenium element was used to coat NiTi alloys with different thicknesses. The coating process was performed using the thermal evaporation technique. Scanning electron microscopy-Energy Dispersive X-ray Analysis measurements revealed that the surfaces of the samples were well covered. Also, the atomic force microscope device determined the surface roughness of the alloys. The roughness of the surface increased after the coating process. The Tafel test was accomplished to determine the biocompatibility of the coated and uncoated alloys in an artificial body fluid. The corrosion test reveals that Se-coated NiTi alloys have high corrosion resistance.

  • MakaleAçık Erişim2022Scopus SJRQ2
    Biocompatible PLA/PCL blends nanocomposites doped with nanographite: Physico-chemical, and thermal behaviour

    Qader, Ibrahim Nazem; Pekdemir, Mustafa Ersin; Coşkun, Meltem; Kanca, Muhammed Sait; Kök, Mediha; Dağdelen, Fethi

    There is a great interest in nano-graphite due to its wide application in nanotechnology and important physical properties. Nanocomposites based on polymers and blends are important in the development of traditional polymers and in improving their usage areas. The aim of this study is to improve physico-chemical, and thermal behavior of poly(lactic acid) / poly(ε-caprolactone) (PLA/ PCL) blend by doping nano-graphite (NG) with different amounts and make the characterization of these nano-composites. It was observed that NG affected the temperature at which nanocomposites decompose. Also, the nanoparticles incorporated in the polymer blend become locked between the polymer filaments, speeding up the composites' decomposition. NG has significantly higher melting and evaporation temperature than PLA and PCL, so more residues were left as the quantity of NG rose. There was no significant change in the Tg and Tm peaks in the DSC experiment due to the inclusion of NG. While the NG particles raised the enthalpy of phase transition in general. The sharpness of the XRD peaks and the crystallinity of the nanocomposites both enhanced as the amount of NG in the blend was increased. Shape memory has been demonstrated to be a remarkable characteristic of thermos-sensitive PLA / PCL blend. Although the trained nanocomposite recovered most of its predetermined shape, increasing NG concentration in the composite may diminish its recovery behavior because.

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