Chemical Engineering / Kimya Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/14
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Article Citation - WoS: 62Citation - Scopus: 72Diatomite Reinforced Chitosan Composite Membrane as Potential Scaffold for Guided Bone Regeneration(Elsevier Ltd., 2017) Tamburacı, Sedef; Tıhmınlıoğlu, FundaIn this study, natural silica source, diatomite, incorporated novel chitosan based composite membranes were fabricated and characterized for bone tissue engineering applications as possible bone regeneration membrane. The effect of diatomite loading on the mechanical, morphological, chemical, thermal and surface properties, wettability and in vitro cytotoxicity and cell proliferation on of composite membranes were investigated and observed by tensile test, atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), protein adsorption assay, air/water contact angle analysis and WST-1 respectively. Swelling studies were also performed by water absorption capacity determination. Results showed that incorporation of diatomite to the chitosan matrix increased the surface roughness, swelling capacity and tensile modulus of membranes. An increase of about 52% in Young's modulus was achieved for 10 wt% diatomite composite membranes compared with chitosan membranes. High cell viability results were obtained with indirect extraction method. Besides, in vitro cell proliferation and ALP activity results showed that diatom incorporation significantly increased the ALP activity of Saos-2 cells cultured on chitosan membranes. The novel composite membranes prepared in the present study with tunable properties can be considered as a potential candidate as a scaffold in view of its enhanced physical & chemical properties as well as biological activities for bone tissue engineering applications.Article Citation - WoS: 2Citation - Scopus: 3Evaluation of Boron Industrial Solid Waste in Composite Materials(Taylor and Francis Ltd., 2018) Topaloğlu Yazıcı, Demet; Çetinkaya, HayrullahBoron industrial solid waste is used as reinforcement for preparing composite materials. This waste has boron trioxide which holds unique properties may affect the surface or interface of the composite. The prepared composites are characterized in order to determine the dispersion and the structure by means of inverse gas chromatography (IGC), Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy (SEM) and X-ray diffraction (XRD). There is a strong relation between the dispersion of reinforcement and the properties of newly formed composite. The dispersive component of the surface energies of the composites and components are determined by IGC. This parameter is difficult to measure by other methods and it is related to the wettability and adhesive characters of solid materials. The effect of compounding ratios of reinforcement is also examined. Furthermore, XRD diffractograms and SEM images of composites showed well dispersion. Thermal analysis revealed that the addition of the boron industrial solid waste to the polymer increased the thermal stability of pure polymer. Infrared spectra of the composites indicated that the composites were formed from the waste reinforcement and the polymer matrix.Article Citation - WoS: 73Citation - Scopus: 77Zinc Oxide and Zinc Hydroxide Formation Via Aqueous Precipitation: Effect of the Preparation Route and Lysozyme Addition(Elsevier Ltd., 2015) Top, Ayben; Çetinkaya, HayrullahAqueous precipitation products of Zn(NO3)2 and NaOH obtained by changing the method of combining the reactants and by using lysozyme as an additive were investigated. In the case of single addition method, octahedral ε-Zn(OH)2 and plate-like β-Zn(OH)2 structures formed in the absence and in the presence of lysozyme, respectively. Calcination of these Zn(OH)2 samples at 700 °C yielded porous ZnO structures by conserving the template crystals. When zinc source was added dropwise into NaOH solution, predominantly clover-like ZnO crystals were obtained independent of lysozyme addition. Mixed spherical and elongated ZnO morphology was observed when NaOH was added dropwise into Zn(NO3)2 solution containing lysozyme. Lysozyme contents of the precipitation products were estimated as in the range of ∼5-20% and FTIR indicated no significant conformational change of lysozyme in the composite. These results suggest that lysozyme-ZnO/Zn(OH)2 composite materials may have a value as an antibacterial material.Article Citation - WoS: 19Flexible Poly(vinyl Chloride)-Zeolite Composites for Dye Adsorption From Aqueous Solutions(Taylor and Francis Ltd., 1996) Balköse, Devrim; Ulutan, Sevgi; Çakıcıoğlu Özkan, Seher Fehime; Ülkü, Semra; Köktürk, UğurFlexible poly(vinyl chloride) (PVC) composites having natural zeolite clinoptillolite were prepared by plastisol-plastigel technology. Adsoption of methylene blue on each raw material and on composites was studied both from an equilibrium and a rate approach. It was observed that the adsorption capacity of zeolite decreased when it was embedded in composites. The equilibrium uptake of methylene blue increased with an increasing zeolite fraction in composites. Methylene blue was adsorbed from a 0.02 g·cm-3 aqueous solution slowly, but was nearly adsorbed completely with a composite having a 0.3 volume fraction of zeolite. The effective diffusion coefficient of methylene blue in composites was of the order of 10-13 m2·s-1 and decreased with increasing filler fraction.Article Citation - WoS: 54Citation - Scopus: 62Sic-Particulate Aluminum Composite Foams Produced by Powder Compacts: Foaming and Compression Behavior(Springer Verlag, 2003) Elbir, Semih; Yılmaz, Selahattin; Toksoy, Ahmet Kaan; Güden, Mustafa; Hall, Ian W.The foaming behavior of SiC-particulate (8.6% by volume) aluminum composite powder compacts contained Titanium Hydride blowing agent was investigated by heating above the melting temperature (750°C) in a pre-heated furnace. Aluminum powder compacts were also prepared and foamed using similar compaction and foaming parameters in order to determine the effect of SiC-particulate addition on foaming and compression behavior. The linear expansions of the compacts at various furnace holding times were ex situ determined. Optical and scanning electron microscopy techniques were used to characterize prepared and deformed foams microstructures. The SiC-particulate addition was found to increase the linear expansion and reduce the extent of the liquid metal drainage and cell coarsening of the aluminum compacts. The composite foam samples also showed higher compressive stresses, but a more brittle behavior as compared with aluminum foams.