Master Degree / Yüksek Lisans Tezleri

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

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Author: search.filters.author.Tanoğlu, MetinSubject: search.filters.subject.Polymeric composites

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Now showing 1 - 6 of 6
  • Master Thesis
    Preparation and Characterization of Calcite (caco3) Particulate Filled Thermoplastic Composites
    (Izmir Institute of Technology, 2014) Kızıltepe, Esin; Tanoğlu, Metin
    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
    Tribological Behaviour of Polymer Nanocomposities Containing Tungsten Based Nanoparticles
    (Izmir Institute of Technology, 2007) Karal, Kazım; Tanoğlu, Metin
    The use of nanostructured fillers in epoxy systems has a significant role on the development of thermosetting composites. Recent investigations on inorganic nanoparticles filled polymer composites reveal their significant potential in producing materials with low friction and/or high wear resistance. In the present study, epoxy nanocomposites and fiber reinforced polymer (FRP) composites were prepared with the addition of tungsten based nanostructured particles which are produced by mechanical alloying. The effects of the nanostructured additives on the tribological, mechanical and thermal properties of composite laminates and nanocomposites were investigated. Composite laminates with and without filler were manufactured by using hand lay-up technique and cured under compression. It was found that tungsten based particle loading has no significant effect on the flexural properties of the nanocomposites and the composite laminates, and the tensile properties of the nanocomposites. It was found that while the addition of 3 wt. % of nanoparticles increases the hardness values, it significantly improves the wear resistance of nanocomposites. Furthermore, the significant improvement on the wear resistance was observed with the addition of 3 wt. % W-SiC-C (24h mechanical milling) powder onto the surface of fiber reinforced epoxy. The worn surfaces were examined with scanning electron microscopy (SEM) and the results revealed that wear mechanisms are altered due to the presence of nanoparticles in the matrix. Differential scanning calorimetry (DSC) results showed that nanoparticles have no significant effect on glass transition temperatures (Tg) of nanocomposites. Incorporation of nanoparticles increased the thermo mechanical properties of nanocomposites and composite laminates; including the storage and loss modulus and Tg.
  • Master Thesis
    Preparation and Physical Characterization of Clay/Epdm Nanocomposites
    (Izmir Institute of Technology, 2008) Karşal, Çiçek; Tanoğlu, Metin
    Polymer/clay nanocomposites have been extensively studied in recent years because they often exhibit improved properties different from their micro and macrocomposite counterparts. Addition of organophilic layered silicates to the polymer produces effective polymer nanocomposites by intercalation of macromolecules into the interlayer spaces. The performance of polymer/clay composites is not only related to the nature of the clay but also to the reinforcing mechanism of filler and the preparation conditions.In this study, the effects of mixing conditions and effect of aging on mechanical,physical and thermal properties of ethylene-propylene-diene rubber (EPDM)/Organo modified montmorillonite (OMMT) nanocomposites were studied at two different clay loadings 5 wt.% and 10 wt.%. EPDM/OMMT nanocomposites were prepared by melt blending method. The experimental results of X-ray diffraction (XRD) and scanning electron microscopy showed that the organically modified MMT existed in the form of an intercalated structure and that was exfoliated in EPDM matrix depending on the mixing conditions. XRD patterns showed that the interlayer distance of the organically modified clay was 30.9A, which was larger than those of the unmodified clay (14.6A).The mechanical evaluation of the nanocomposites was performed by tensile and tear testing. The mechanical tests showed that the properties of nanocomposites were significantly improved with addition of OMMT. The effects of the processing conditions were manifested in both the morphology and mechanical properties, which showed significant increase when optimized process conditions are applied. In addition, chemical test was performed on the nanocomposites to monitor the degradation of the mechanical properties. It was found that the reduction of the mechanical properties of nanocomposites after aging process is lower as compared to those of neat EPDM.
  • 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
    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
    Processing and Characterization of Polymer Based Composites With Superior Impact Resistance
    (Izmir Institute of Technology, 2003) Seyhan, Abdullah Tuğrul; Tanoğlu, Metin
    Fiber reinforced polymeric composite materials have recently gained widespread use in military, transportation, energy and civil engineering applications. Resin Transfer Molding (RTM) and Vacuum Assisted Resin Transfer Molding (VARTM) process have become important in the manufacture of these types of composites. In those techniques, use of fiber preforms offer some distinct advantages. Using thermoplastic binders that bond the fabrics together allows the plies to be consolidated into near net shape preform.In the present work, glass preforms were consolidated by application of heat and pressure over plies of the glass fabrics that were coated with various concentration of thermoplastic polyester binder. Composite laminates with and without binder were fabricated by utilizing VARTM technique. The peel strength of the preforms with various binder contents was measured to determine the optimum binder concentration. The highest peel strength was obtained from preforms that were prepared with about 9 wt.% of the binder. Preform compression test was also performed using universal test machine with preforms composed of eight plies of glass fabrics with binder (3,6 and 9 wt.%) and without binder. It was observed that the binder has significant effect on the degree of preform compaction. The highest thickness reduction and therefore fiber volume fraction of the preforms was reached via 3 wt.% of binder. The flexural strength and modulus, compressive strength and modulus through ply-lay up and in-plane loading directions, apparent interlaminar shear strength, mode I interlaminar fracture toughness of the composites with and without binder were measured to evaluate the effects of the binder on the mechanical properties of the composite plates. It was found that the flexural strength, mode I interlaminar fracture toughness of the E-glass/polyester composite system decreases 30 and 40 percentage, respectively due to the presence of 3 wt.% and 6 wt.% of binder. On the other hand, the flexural modulus of the composite increases while the apparent interlaminar shear strength remains almost constant by the introduction of the binder. The ply-lay up compressive strength and modulus were found to increase up to 3 wt.% of binder and decrease upon further addition of binder. The same findings are valid for the compressive strength and modulus through in-plane loading direction. Ballistic test was performed on E-glass/polyester composite panels according to NATO standards 2920 using 1.1-gr. fragment-simulating projectiles (FSPs) to evaluate the effects of the binder on the ballistic performance of the E-glass/polyester composite laminates. The ultrasonic C-scan test method was used to monitor the extent of the damage on the panels due to ballistic impact. It was seen that the damage on the ballistically impacted composite panels decreases with increasing binder. A model matrix material was prepared adding various concentrations of the binder to the reacting resin system in order to follow the extend of binder dissolution within the matrix resin. It was found that there is no complete dissolution of the binder in the matrix resin.
  • Master Thesis
    Layered Silicate / Polypropylene Nanocomposites
    (Izmir Institute of Technology, 2006) Işık, Kıvanç; Tanoğlu, Metin
    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.