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    Advances in PEKK Thermoplastic Composites: Reinforcing With MWCNTs and GNPs for Enhanced Performance
    (Wiley, 2025) Ferik, Erdem; Yilmaz, Sukran Guney; Birak, Selahattin Berat; Demirel, Merve Ozkutlu; Oz, Yahya; Kaboglu, Cihan
    Polyetherketoneketone (PEKK) is a highly regarded material in polymer science due to its outstanding thermal stability, mechanical strength, and chemical resistance. Despite substantial research on PEKK composites reinforced with CNTs and GNPs, two primary challenges remain: inconsistent glass transition temperature behavior at varying filler contents, leading to unpredictable shifts in both thermal and mechanical performance, and the absence of direct comparisons under uniform processing conditions that would allow quantitative evaluation of each filler's effect. In this work, PEKK/MWCNT and PEKK/GNP nanocomposites were produced via the same hot-press molding protocol and systematically evaluated for thermal and mechanical performance, electrical conductivity (using S-value analysis) and microstructural morphology. A range of mechanical tests, including tensile, Charpy impact, and hardness tests, were conducted alongside physical analyses such as differential scanning calorimetry (DSC), thermogravimetric analysis, dynamic mechanical analysis (DMA), thermal conductivity, electrical conductivity, and scanning electron microscopy (SEM). The results demonstrated that both MWCNTs and GNPs significantly enhanced PEKK's properties. The incorporation of MWCNTs raised the glass transition temperature (T-g) to 169 degrees C and the crystallization temperature (T-c) to 327 degrees C, whereas GNPs increased the decomposition temperature (T-d) to 572 degrees C. Adding 1 wt.% of either nano-additive notably improved tensile and flexural strength, while an optimal concentration of 0.1 wt.% was determined for Charpy impact performance. Additionally, higher concentrations resulted in exceptional electrical and thermal conductivity.
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    High-performance thermoplastic nanocomposites for aerospace applications: A review of synthesis, production, and analysis
    (Sage Publications Ltd, 2026) Yilmaz, Sukran Guney; Ferik, Erdem; Birak, Selahattin Berat; Demirel, Merve Ozkutlu; Oz, Yahya; Kaboglu, Cihan
    Thermoset polymers are cured under natural or synthetic created conditions and retain their solid form when exposed to heat. Unlike thermosets, thermoplastics melt when exposed to heat after production. Thermoplastics are preferred as raw materials because they can be easily shaped after production, have a high shelf life and are recyclable. In this regard, the prominence of high-performance engineering polymers in recent years has led to the preference of alternative polymers to thermosets. High-performance engineering thermoplastics include thermoplastics such as polyphenylene-sulfide (PPS), polyether-ether-ketone (PEEK), polyether-ketone-ketone (PEKK), polyphenylene-ether, polysulfone,polyoxadiazole, polyimide, polyether-amide, polyether-amide-imide, polynaphthalene, and polyamide-imide. These polymers exhibit application potential in aerospace, defense, automotive, marine, energy, and medical sectors. In challenging conditions such as high pressure, temperature, and corrosive environments, they possess high service temperatures, enhanced mechanical and physical properties, preferable chemical resistance as well as out-of-autoclave and rapid processing properties. In this review article, nanomaterial production methods (bottom-up and top-bottom) are mentioned. In the following sections, PPS, PEEK, and PEKK thermoplastics are explained, and carbon- and boron-based nano additives used in constructing nanocomposites are investigated. In the last section, PPS, PEKK, and PEEK polymer nanocomposites are investigated.
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    Tailored mechanical and thermal properties of polyphenylene sulphide (PPS) reinforced with nano-materials
    (Sage Publications Inc, 2025) Yilmaz, Sukran Guney; Demirel, Merve Ozkutlu; Oz, Yahya; Kaboglu, Cihan
    Various approaches have been proposed to enhance the thermal conductivity of polymers, primarily by incorporating high thermal conductivity nano-additives into the polymer matrix. In this study, graphene nano-platelet (GNP) and titanium diboride (TiB2) were used as nano-additives while polyphenylene sulphide (PPS) was used as polymer matrix. Materials were dry-mixed in predetermined weight ratios and produced using compression molding. Tensile as well as hardness testing, thermal conductivity measurements and scanning electron microscopy analyses were conducted on the produced composite materials. Results show that an improvement in thermal conductivity values was observed. When 0.1 wt% TiB2 is added, there is a 21% increase in the thermal conductivity compared to pure PPS, whereas the addition of 0.1 wt% GNP results in a 15% increase. Regarding mechanical properties, an increase of 11% in the tensile strength was observed with the addition of 0.1 wt% GNP.