Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 1Citation - Scopus: 1Epoxy Matrix Nano Composites: Modulus, Strength and Ductility Enhancement Through Auxeticity of Α-Cristobalite Filler(Elsevier, 2023) Güden, Mustafa; Ülker, Sevkan; Movahedi, NimaThe negative Poisson's ratio (NPR) nano-size ?-Cristobalite particle/epoxy composites were prepared and tensile tested. The elastic modulus and strength of the composites were improved as the particle volume fraction increased from 0 to 0.02. Unlike the conventional particle reinforced composites, the fracture strain increased with the nano ?-Cristobalite addition, an effect which was ascribed to the intrinsic NPR behavior of the filler. © 2023 Elsevier B.V.Article Citation - WoS: 14Citation - Scopus: 13Investigations of Polyamide Nano-Composites Containing Bentonite and Organo-Modified Clays: Mechanical, Thermal, Structural and Processing Performances(Walter de Gruyter GmbH, 2021) Akar, Alinda Öykü; Yıldız, Ümit Hakan; Tayfun, ÜmitPolyamide 6 (PA) matrix was reinforced with Na-activated bentonite, amino functional silane treated bentonite and organo-modified clays at different concentrations. The preparation of composites was carried out using melt-blending method and the test samples were prepared by injection-molding process. Mechanical, thermal, structural and processing investigations of PA based composites were reported performing via tensile, hardness, and impact tests, differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction analysis (XRD) and force measurements, respectively. According to mechanical test results, additions of fillers to PA matrix caused slight improvements for tensile strength and modulus parameters. Silane treated BNT exhibited improvement in mechanical results compared to Na-activated bentonite additions. Thermal studies revealed that decomposition and melting temperatures of PA shifted to higher values after inclusion of clay into polymer matrix. Results confirmed that organo-clay and bentonite additions with their lower filling ratios yielded enhancements for the mechanical and thermal performance of polyamide.Article Citation - WoS: 27Citation - Scopus: 34Chitosan/Montmorillonite Composite Nanospheres for Sustained Antibiotic Delivery at Post-Implantation Bone Infection Treatment(IOP Publishing Ltd., 2019) Kımna, Ceren; Değer, Sibel; Tamburacı, Sedef; Tıhmınlıoğlu, FundaDespite the advancements in bone transplantation operations, inflammation is still a serious problem that threatens human health at the post-implantation period. Conventional antibiotic therapy methods may lead to some side effects such as ototoxicity and nephrotoxicity, especially when applied in high doses. Therefore, local drug delivery systems play a vital role in bone disorders due to the elimination of the disadvantages introduced by conventional methods. In the presented study, it was aimed to develop Vancomycin (VC) and Gentamicin (GC) loaded chitosan-montmorillonite nanoclay composites (CS/MMT) to provide required antibiotic doses to combat post-implantation infection. CS/MMT nanocomposite formation was supplied by microfluidizer homogenization and spherical drug carrier nanoparticles were obtained by electrospraying technique. Three factors; voltage, distance and flowrate were varied to fabricate spherical nanoparticles with uniform size. Emprical model was developed to predict nanosphere size by altering process variables. Nanospheres were characterized in terms of morphology, hydrodynamic size, zeta potential, drug encapsulation efficiency and release profile. Drug loaded nanospheres have been successfully produced with a size range of 180-350 nm. Nanocomposite drug carriers showed high encapsulation efficiency (80%-95%) and prolonged release period when compared to bare chitosan nanospheres. The drug release from nanocomposite carriers was monitored by diffusion mechanism up to 30 d. The in vitro release medium of nanospheres showed strong antimicrobial activity against gram-positive S. aureus and gram-negative E. coli bacteria. Furthermore, it was found that the nanospheres did not show any cytotoxic effect to fibroblast (NIH/3T3) and osteoblast (SaOS-2) cell lines. The results demonstrated that the prepared composite nanospheres can be a promising option for bone infection prevention at the post implantation period.Article Citation - WoS: 39Citation - Scopus: 39Polarized Emission From Cspbbr3 Nanowire Embedded-Electrospun Pu Fibers(IOP Publishing Ltd., 2018) Güner, Tuğrul; Topçu, Gökhan; Savacı, Umut; Genç, Aziz; Sarı, Emre; Demir, Mustafa MuammerInterest in all-inorganic halide perovskites has been increasing dramatically due to their high quantum yield, band gap tunability, and ease of fabrication in compositional and geometric diversity. In this study, we synthesized several hundreds of nanometer long and ∼4 nm thick CsPbBr3 nanowires (NWs). They were then integrated into electrospun polyurethane (PU) fibers to examine the polarization behavior of the composite fiber assembly. Aligned electrospun fibers containing CsPbBr3 NWs showed a remarkable increase in the degree of polarization from 0.17-0.30. This combination of NWs and PU fibers provides a promising composite material for various applications such as optoelectronic devices and solar cells.Article Citation - WoS: 13Citation - Scopus: 15Synthesis of Poly-2 Methacrylate-Montmorillonite Nanocomposite Via in Situ Atom Transfer Radical Polymerization(Cambridge University Press, 2008) Oral, Ayhan; Shahwan, Talal; Güler, ÇetinThe poly-2-hyroxyethyl methacrylate (PHEMA)/clay nanocomposite was synthesized by in situ atom transfer radical polymerization (ATRP) from initiator moieties immobilized within the silicate galleries of the clay particles. To produce organically modified montmorillonite (MMT) that has ATRP initiator moiety, a new catalyst that consists of quaternary ammonium salt moiety and an initiator moiety was synthesized. This initiator was intercalated into the interlayer spacing of the MMT. The polymerization reaction was carried out in a mixed solvent system consisting of methyl ethyl ketone and 1-propanol at 50 °C, using the initiator that has been already synthesized with a copper bromide catalyst. The 2, 2′-bipyridyl (bpy) complex was used as ligand. The products were characterized via Fourier transform infrared, nuclear magnetic resonance (1H NMR, 12C NMR), transmission electron microscopy, x-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. © 2008 Materials Research Society.Article Citation - WoS: 38Citation - Scopus: 42Layered Clay/Epoxy Nanocomposites: Thermomechanical, Flame Retardancy, and Optical Properties(John Wiley and Sons Inc., 2008) Kaya, Elçin; Tanoğlu, Metin; Okur, SalihIn this study, layered clay/polymer nano-composites were developed based on epoxy resins and montmorillonite as the nanoplatelet reinforcement. Clay particles were treated with hexadecyltrimethylammonium chloride (HTCA) through an ion exchange reaction. In this way, Na+ interlay er cations of the clay is exchanged with onium cation of the surfactant that turns the hydrophilic clays (MMT) to organophilic (OMMT) characteristics. Thermal analysis results revealed that the glass transition temperature (Tg) and the dynamic mechanical properties including the storage and loss modulus of the neat epoxy resin increases by the incorporation of clay particles. It was also found that flame resistance of the polymer is improved by the addition of the clay particles.Article Citation - WoS: 5Citation - Scopus: 6Tailored Ceo2 Nanoparticles Surface in Free Radical Bulk Polymerization of Methyl Methacrylate(American Chemical Society, 2013) Tunusoğlu, Özge; Demir, Mustafa MuammerPolymerization of monomer/nanoparticle dispersion, namely in situ polymerization, has been frequently used for the fabrication of polymer nanocomposites. However, the interference of nanoparticle surface with polymerization in the course of composite formation has been tacitly neglected. In this work, surface-functionalized ceria nanoparticles were prepared using various capping agents: 3-(mercaptopropyl) trimethoxy silane, thioglycolic acid, 3-mercaptopropionic acid, and hexadecyltrimethyl ammonium bromide. Both in situ and ex situ approaches were applied for surface functionalization. The particles were dispersed into methyl methacrylate and free radical polymerization was carried out. The process of nanocomposite formation was examined in terms of conversion, molecular weight, and molecular weight distribution. The polymerization responded merely to the in situ functionalized particles. Regardless of the capping agents used, the particles function as a retarder and inhibitor. Their interaction with polymerization medium showed many complexities such that molecular weight was found to be strongly dependent on the capping agent employed.Article Citation - WoS: 8Citation - Scopus: 8Highly Efficient Orange–red Electroluminescence From a Single Layer Meh-Ppv Hybrid Pled(Elsevier Ltd., 2012) Saygılı, Gamze; Ünal, Gülçin; Özçelik, Serdar; Varlıklı, CananIn this study, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] end capped with polyhedral oligomeric silsesquioxanes (MEH-PPV-POSS): cadmium sulfide selenide quantum dots (CdS0.75Se0.25 QDs) nanocomposites based OLEDs were fabricated. By the addition of CdS0.75Se0.25QDs into the polymer active layer, a considerable enhancement was observed in terms of hole and electron injection in devices. Additionally, the presence of QDs reduced the interchain interaction of polymer that resulted in narrower electroluminescence (EL) spectrum. The device structure of ITO/PEDOT: PSS/MEH-PPV-POSS: 25 wt% CdS0.75Se0.25/Ca (40 nm)/Al demonstrated the best performance with a brightness of 8672 cd/m 2 at 10 V, current efficiency of 2.5 cd/A at 8 V, and an EQE of 0.55% at 150 mA/cm2 .