Yazar "Oz, Yahya" seçeneğine göre listele
Listeleniyor 1 - 5 / 5
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe 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, CihanPolyetherketoneketone (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.Öğe Effect of graphene nanoplatelet and multi-walled carbon nanotube additives on polyphenylene sulfide nanocomposites(Sage Publications Ltd, 2025) Guney Yilmaz, Sukran; Ferik, Erdem; Berat Birak, Selahattin; Ozkutlu Demirel, Merve; Kaboglu, Cihan; Oz, YahyaThe performance of current materials remains inadequate in the face of advancing technology and challenging working conditions. Due to the advantages and versatility, they offer, composite materials are utilized in numerous industries. Polyphenylene sulfide (PPS) has attracted significant interest in the aerospace industry due to its lightweight, high strength, high-temperature resistance, availability, and mechanical and physical properties. In this study, PPS was reinforced with multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) to enhance its mechanical properties. Composite materials were produced by mixing PPS matrix material with nanofillers at different weight ratios and then subjected to compression molding. The specified tests were applied to the produced composite materials. When the thermal conductivity properties are examined, it is observed that there is a 490% increase when 10 wt% GNP is added, and a 45% increase when 10 wt% MWCNT is added. When 10 wt% of MWCNT is added to pure PPS, it has been observed that electrical conductivity at mid-frequency measurements increases by 222 % making it a conductive material. Uniform nanofiller distribution is crucial for optimal impact and mechanical performance. Agglomeration reduces properties such as tensile strength, hardness, and impact resistance.Öğe 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, CihanThermoset 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.Öğe Mechanical response of carbon fiber reinforced epoxy composite parts joined with varying bonding techniques for aerospace applications(Elsevier Sci Ltd, 2024) Karaboga, Furkan; Golec, Fatih; Yunus, Doruk Erdem; Toros, Serkan; Oz, YahyaAs a result of the widespread use of composite materials in primary structures of aerospace platforms, composite joining became more crucial. This study addresses the effect of joining methods on the strength of composite joints experimentally, numerically and analytically. Single lap joint shear strengths of carbon fiber reinforced epoxy composite parts joined by mechanical fastening with a pop and solid rivet, secondary bonding with a paste adhesive, co-curing and co-bonding techniques were compared. In addition, the effect of adhesive thicknesses (0.2, 0.4, 0.6, 0.76 mm) on the single lap shear strength was investigated. Carbon fiber reinforced composite (CFRP) samples were produced according to the ASTM 5868 standard. After the production of samples with varying joining methods, single lap shear tests were implemented. Moreover, the interface damage in the composites was examined by use of a scanning electron microscope (SEM) for the purpose of studying the damage mechanism. Fracture mechanisms corresponding with bonding methods were also assessed by examining the fracture surface of the composite samples. Furthermore, results were analyzed by Hypermesh, ABAQUS and ESAComp. For instance, the co-bonded sample with an adhesive film exhibits an experimental shear strength of 24.03 MPa which deviates only 3 % from the numerical expectation.Öğe 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, CihanVarious 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.
