Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Department: search.filters.department.Thesis (Master)--İzmir Institute of Technology, Mechanical EngineeringSubject: search.filters.subject.Polymeric composites

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Now showing 1 - 5 of 5
  • Master Thesis
    Effects of Surface Treatments on Fatigue Performance of Adhesively Bonded Single Lap Joint Carbon Fiber Based Polymer Composites
    (01. Izmir Institute of Technology, 2024) Gürbüz, Ahmet Ayberk; 01. Izmir Institute of Technology
    Yeni teknolojilerin ortaya çıkışını takip eden dönemde, alternatif birleştirme teknikleri karbon elyaf takviyeli polimerleri içeren uygulamalarda geleneksel mekanik bağlantı elemanlarının yerini almaya başlamıştır. Gerilme konsantrasyonu, ağırlık, radar sinyallerinin emilmesi ve korozyon gibi mekanik bağlantı elemanlarıyla ilgili zorlukların çoğu, CFRP'ler alanında yapıştırıcı bağların kullanılmaya başlanmasıyla etkili bir şekilde ele alınmıştır. Bununla birlikte, kirletici maddelerin varlığı ve yüzey tabakasındaki matris fazlalığı da dahil olmak üzere çeşitli faktörler yapışma gücü üzerinde önemli bir etkiye sahiptir. Bu tezin amacı, yüzey işleminin uygulanmasının, yapışkan olarak bağlanmış karbon elyaf takviyeli polimer kompozit plakaların yorulma performansı üzerindeki etkilerini incelemektir. [45/-45/45/0/-45/90]s istifleme sırasına sahip karbon fiber takviyeli polimer laminatlar, otoklav tekniği ile tek yönlü prepregler kullanılarak üretilmiştir. Karbon fiber takviyeli polimer laminatların yapışma yüzeyine lazer işlemi ve elektrospinning olmak üzere iki farklı yüzey işlemi uygulanmıştır. Farklı yüzey işlemlerine tabi tutulan kompozitlerin yorulma performansını araştırmak için yük kontrollü çekme-germe yorulma testleri yapılmıştır. Numuneler, statik tek bindirmeli kesme testlerinden belirlenen ortalama maksimum tek bindirmeli kesme yükünün %30 ila %50'si arasında değişen gerilme seviyelerinde döngüsel yüklemeye tabi tutulmuştur. Yüzey işlemlerinin yapışma yüzeyinin yorulma performansı üzerindeki etkileri SEM görüntüleri, sertlik bozulması ve Wöhler eğrileri kullanılarak yorumlanmıştır.
  • Master Thesis
    Process Parameters and Mechanical Properties of Geopolymer Glass Foam Structures
    (01. Izmir Institute of Technology, 2020) Polat, Dilan; Güden, Mustafa; Güden, Mustafa; 01. Izmir Institute of Technology; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering
    The effects of waste-glass powder particle size (23 and 72 μm), solid/liquid ratio (S/L=1, 1.5 and 2) and aluminum foaming agent content (2-20 wt%) on the expansion behavior of geopolymer slurries were investigated experimentally. Geopolymer slurries were prepared using an activation solution of NaOH (8M) and sodium silicate (10% NaOH, 27% SiO2). The expansions and temperatures of the slurries were measured in-situ using a laser distance meter and a thermocouple, respectively. Few geopolymer foams were sintered at 600, 700, 725 and 750 °C. The compression strengths and thermal conductivities of foam samples were also determined. The expansion of slurries continued until the temperature increased to 85-90 °C. At this temperature, the slurry evaporation; hence, increased S/L ratio limited both the hydrogen release rate and geopolymerization reaction. As the content of Al increased, the final foam density decreased, while the coarse powder slurries resulted in lower densities (240-530 kg m-3) than the fine powder slurries (280-530 kg m-3). Three crystal phases, muscovite, sodium aluminum silicate hydrate and thermonitrite, were determined after the geopolymerization. The muscovite formation was noted to be favored at higher S/L ratios. The partial melting of glass particles started after ~700 °C, while sintering above this temperature decreased the final density. The reduced density above 700 °C was ascribed to the release of carbon dioxide by the decomposition of thermonitrite. Both the compressive strength and thermal conductivity of geopolymer and sintered foams increased at increasing densities and were shown to be comparable with those of previously investigated geopolymer and glass foams. The geopolymer foams sintered at 750 °C exhibited the lowest density and the highest compressive strength.
  • Master Thesis
    Preparation and Characterization of Calcite (caco3) Particulate Filled Thermoplastic Composites
    (Izmir Institute of Technology, 2014) Kızıltepe, Esin; Tanoğlu, Metin; Tanoğlu, Metin; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Nano-sized particle filled polymer composites have been received great attention of researchers and industrial institutions in recent years due to their unique properties, save as high mechanical strength, thermal and solvent resistance as compared to traditional composite materials. In this study, calcium carbonate (CaCO3) filled polypropylene (PP) and Polyethylene (PE) composite blends were prepared using a co-rotational twin screw extruder with a calcite particle content varying from 0 to 30 wt. % . Tensile and three-point bending test coupons were prepared by injection moulding using the extruded composite blends. The effects of calcite reinforcement (with and without stearic acid treatment) on the microstructural, thermal and mechanical properties of neat PP and PE were investigated. Nano-CaCO3 powders were characterized by means of Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The PE and PP were characterized via differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Analytical results were compared with the experimental results.
  • Master Thesis
    Mechanical and Thermal Properties of Non-Crimp Glass Fiber Reinforced Composites With Silicate Nanoparticule Modified Epoxy Matrix
    (Izmir Institute of Technology, 2006) Bozkurt, Emrah; Tanoğlu, Metin; Tanoğlu, Metin; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In the present study, epoxy based nanocomposites were prepared with modified and unmodified silicate nanoparticules to apply as a matrix resin for non-crimp glass fiber reinforced polymer composites. The effects of the silicate nanoparticules on the mechanical, thermal and flame retardancy properties of glass reinforced composites were investigated. Laminates were manufactured with hand lay-up technique and cured under compression. To intercalate the layers and obtain better dispersion of silicate layers within the matrix, silicate (montmorillonite, MMT) particules were treated with hexadecyltrimethylammonium chloride (HTAC) surfactants. X-ray diffraction of silicates with and without surface treatment indicated that intergallery spacing of layered silicate increased with surface treatment. Tensile tests showed that silicate loading had minor effect on the tensile strength and modulus of the composite laminates. Flexural properties of laminates were improved with the addition of silicate due to the improved interface between glass fibers and epoxy matrix. With the addition of modified MMT (OMMT), interlaminar shear strength (ILSS) of laminates decreased slightly but fracture toughness (KIC) of laminates were increased. The fracture surfaces were examined with scanning electron microscopy (SEM) and the results revealed that fracture mechanisms were altered due to the presence of silicates in the matrix. Differential scanning calorimetry (DSC) results showed that modified silicate particules increase the glass transition temperatures (Tg) of composite laminates. Incorporation of OMMT particules increased the dynamic mechanical properties of non-crimp glass fiber reinforced epoxy composites. It was found that the flame resistance of composites was improved due to silicate particule additions into the epoxy matrix.
  • Master Thesis
    Layered Silicate / Polypropylene Nanocomposites
    (Izmir Institute of Technology, 2006) Işık, Kıvanç; Tanoğlu, Metin; Tanoğlu, Metin; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Layered silicate nanocomposites are new generation materials that have unique properties obtained by low particulate loadings. In this study, layered silicate/polypropylene nanocomposites were prepared by melt intercalation method.Homopolymer PP alone and maleic anhydride-grafted polypropylene (PPgMA) as a compatibilizer were used as the matrix. Clay (Na+ montmorillonite, MMT) particles were used with and without structural modification to obtain silicate nano-layers within the PP matrix. Structural modification of MMT using hexadecyltrimethyl ammonium chloride (HTAC) was applied to obtain organophilic silicates (OMMT). XRD results demonstrated that the dispersion of the modified silicate layers and compatibilized with PPgMA (OMMT/PPgMA) is better than those for incompatibilized compositions. The addition of silicate layers increased the crystallization temperature of PP as well as the thermal stability, but the melting temperature of the nanocomposites was decreased by the addition of silicate as compared with neat PP. The mechanical characterizations exhibited an increase of 62% on tensile modulus and 15% on tensile stress at break as compared to neat PP due to the improved dispersion of silicate layers within PP in 3 wt.% OMMT/PPgMA/PP nanocomposites. The effect of clay modification and PPgMA compatibilization on the light transmission of PP nanocomposites was characterized by optical transmission analysis. For the OMMT/PPgMA/PP nanocomposites, light transmission was improved as the dispersion was enhanced. The flammability results demonstrated that unmodified MMT and modified OMMT decreased the burning rate of PP nanocomposites. The organic modification of clay and compatibilization decreased the rate of flammability. A decrease of 26% on the burning rate of PP was recorded in 10%wt. OMMT/PPgMA/PP nanocomposites.