Person: ÇAKMAKÇI, EMRAH
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ÇAKMAKÇI
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EMRAH
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Publication Metadata only Allyl Phosphonium Salt-Modified Clay for Photocured Coatings: Influence on the Properties of Polyester Acrylate-Based Coatings(WILEY, 2015) ÇAKMAKÇI, EMRAH; Zeytuncu, Bihter; Cakmakci, Emrah; Kahraman, Memet VezirIn this study, bentonite clay was modified with a phosphonium salt and this modified clay was used to prepare polyester acrylate based coatings to improve their flame retardancy and mechanical properties. Photocured composites were prepared with 1, 2, and 3 wt% phosphonium salt modified clay and for comparison 1 wt% nonmodified clay containing composites were also prepared. Modified clay displayed good dispersion properties due to its increased basal spacing. Composites were characterized by FT-IR and XRD measurements. According to XRD results, it was found that the modified clay was exfoliated in the composites. Furthermore, we investigated the effect of allyl phosphonium salt modified clay on the thermal, mechanical, and flame retardant properties of polyester acrylate based composites coatings. When compared with neat clay containing coatings, modified clay containing photocured coatings exhibited increased modulus and enhanced thermal properties due to increased crosslinking density. Moreover, the presence of the phosphonium salt enhanced the flame retardancy of the polyester based coatings. POLYM. COMPOS., 36:946-954, 2015. (c) 2014 Society of Plastics EngineersPublication Metadata only Quaternary imidazolium-functionalized reactive silica nanoparticles-containing thiol-ene photocured antibacterial hybrid coatings(Elsevier B.V., 2022) ÇAKMAKÇI, EMRAH; Şen F., Kocatürk E., Çakmakçı E., Kahraman M.V.The need for antibacterial coatings is increasing day by day. In this study, coating materials that do not contain antibacterial agents but have antibacterial properties have been developed. First, two different quaternary imidazole compounds were synthesized. Then, silica nanoparticles were modified with these quaternary agents. By using 1%, 3% and 5% modified silica nanoparticles, UV cured coating materials were obtained according to the thiol-ene reaction mechanism. Mechanical, thermal, surface, structural, optical and antibacterial analyzes of the obtained coatings were performed. The analyzes revealed that UV cured antibacterial coating materials have been successfully synthesized and can be used as a new and unique coating material for the coating industry. © 2021 Elsevier B.V.Publication Metadata only Preparation and drug release properties of lignin-starch biodegradable films(WILEY-V C H VERLAG GMBH, 2012) OGAN, AYŞE; Calgeris, Ilker; Cakmakci, Emrah; Ogan, Ayse; Kahraman, M. Vezir; Kayaman-Apohan, NilhanStarch is one of the most commonly available natural polymers which are obtained from agro-sources. It is renewable and abundant in nature. Unfortunately due to its poor mechanical properties and hygroscopic nature, there are some strong limitations to the development of starch-based products. Usually blends of starch are prepared and plasticized with glycerol to improve some of its properties. In this study, lignin was extracted from hazelnut shells and investigated as a potential additive for starch biofilms. The structural characterization of hazelnut lignin was performed by employing UV spectroscopy and Fourier transform infrared (FTIR) spectroscopy. Lignin was blended with corn starch in different ratios to obtain biofilms. Mechanical and thermal properties of the biofilms were enhanced as the lignin amount was increased in the formulations. Water absorption tests were performed at pH 2.0, 4.0, and 6.0. The percent swelling values of the starch/lignin films increased as pH increased. Also, the biofilm exhibiting the best properties was chosen for the drug release studies. Biofilms showed a fast ciprofloxacin (CPF) release within an hour and then the drug release rate decreased. A pH dependent drug release mechanism was also observed according to KoshnerPeppas model. The drug release increased with a decrease in pH.Publication Metadata only Preparation of photo curable highly hydrophobic coatings using a modified castor oil derivative as a sol-gel component(ELSEVIER SCIENCE SA, 2011) ÇAKMAKÇI, EMRAH; Mulazim, Yusuf; Cakmakci, Emrah; Kahraman, Memet VezirModification and use of natural products have gained a lot of interest in recent years due to their environmental friendliness and their availability from different sources. In this study castor oil based photo curable highly hydrophobic coatings were prepared and characterized. Castor oil (CO) was first modified with 3-isocyanato propyl triethoxy silane and then it was hydrolyzed prior to the coating preparation. The resulting precursor was mixed with norbornyl acrylate, hexane diol diacrylate and hydrophobic coatings were prepared with the aid of fluorinated and nonfluorinated alkoxy silane coupling agents. The addition of fluorine showed a significant impact on the properties of the coatings. As the fluorine content was increased in the formulations, flame retardancy and the contact angle values of the coatings increased. The highest amount of fluorine containing coating showed a contact angle of 119 degrees. Then with the addition of nonfluorinatecl alkoxysilane compounds, a contact angle of 130 degrees was reached. Also the effect of post-cure temperature on contact angle values was investigated. (C) 2011 Elsevier B.V. All rights reserved.Publication Metadata only Properties of Thiol-ene Photocurable Highly Hydrophobic and Oleophobic Nanocomposite Coatings on ABS and HIPS Substrates(WILEY-HINDAWI, 2013) ÇAKMAKÇI, EMRAH; Mulazim, Yusuf; Cakmakci, Emrah; Kahraman, Memet V.In this study, thiolene photocurable highly hydrophobic and oleophobic coatings were prepared and characterized. Trimethylolpropane tris(3-mercaptopropionate) and triallyl 1,3,5-triazine-2,4,6(1H,3H,5H)-trione were used for the preparation of the base formulation. Highly hydrophobic and oleophobic coatings were prepared with the aid of a fluorinated acrylate (Fluowet AC 812) and hydrophobic-fumed nanosilica particles. Nanoparticles were added for increasing the surface roughness and also to increase thermal and mechanical properties of the coatings. Coatings were applied on ABS (acrylonitrilebutadienestyrene) and HIPS (high impact polystyrene) substrates. As the fluorine and nanosilica contents were increased in the formulations, flame retardancy, hydrophobicity, and the oleophobicity of the coatings increased. Coatings were found to be highly thermally stable, highly solvent, and chemically resistant. The surface roughness of the coatings increased with the addition of hydrophobic-fumed nanosilica particles. In addition, the relation between the surface energy and the contact angle of the coatings was investigated. (c) 2012 Wiley Periodicals, Inc. Adv Polym Techn 32: E416E426, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21289Publication Metadata only Dimer diamin ve hint yağı esaslı bio-bazlı poliüretan köpük ve hint yağı esaslı alev geciktirici hazırlanması(2022-09-01) ÇAKMAKÇI, EMRAH; KAHRAMAN, MEMET VEZİR; Nasuhoğlu B., ÇAKMAKÇI E., KAHRAMAN M. V.Diizosiyanat ve diollerin reaksiyonu sonucu elde edilen poliüretanlar, günlük hayatımızda geniş bir kullanım alanına sahip polimerlerin başında gelmektedir. Üretilen bu ticari poliüretanlar petrol kaynaklı malzemeler kullanılarak sentezlenir[1]. Petrolün yenilenebilir bir kaynak olmamasından dolayı ve gün geçtikçe petrol fiyatlarının artmasına bağlı olarak, bu tip malzemelerin üretim fiyatının düşürülmesi ve fosil yakıtlara bağımlılığın azaltılması için polimer sentez çalışmalarında yenilebilir kaynakların kullanılması hem ekonomik hem de çevresel açıdan önemlidir. Poliüretan ham maddelerinden poliol sentezinde kullanılan yenilenebilir kaynakların başında, sentetik kimyaya en uygun malzemelerden olan bitkisel yağlar gelmektedir[2]. Bu bitkisel yağlardan yüksek doymamışlığa sahip hint yağı, keten yağı, tung yağı, ayçiçek yağı ve soya yağı bu tür çalışmalarda sıklıkla tercih edilir. Bu çalışmada, petrokimyasalları mümkün olan en az miktara indirmek amacıyla, dimer diamin ve hint yağı kullanılarak otokatalitik poliol ve hint yağı kullanılarak alev geciktirici sentezi yapılmıştır. Sentezlenen monomerler, FTIR tekniğiyle karakterize edilmiştir ve elde edilen köpüklerin mekanik testleri yapılmıştırPublication Metadata only Thermal Properties of Phosphorylated Nanodiamond Reinforced Polyimides(WILEY, 2016) ÇAKMAKÇI, EMRAH; Beyler-Cigil, Asli; Cakmakci, Emrah; Kahraman, Memet VezirRecently, the preparation of nanodiamond-polymer composites has attracted the attention of materials scientists due to the unique properties of nanodiamonds. In this study, novel polyimide (PI)/phosphorylated nanodiamonds (PNDs) composites were prepared. PNDs were achieved from the reaction of methylphosphonic dichloride with nanodiamonds in dichloromethane. Precursor of polyimide, which is the poly(amic acid) (PAA), was successfully synthesized with 3,30, 4,4'-benzophenonetetracarboxylic dianhydride and 4,4'-oxydianiline in the solution of N,N-dimethylformamide. Different ratios of phosphorylated nanodiamond particles were added into PAA solution and four different nanocomposite films were prepared. The amount of PNDs in the composite films was varied from 0 wt% to 3 wt%. The structure, thermal and surface properties of polyimide films were characterized by scanning electron microscopy (SEM), ATR-FTIR, thermogravimetric analysis (TGA), ultraviolet visible spectroscopy, and contact angle. SEM and FTIR results showed that the phosphorylated nanodiamond and PI/PNDs films were successfully prepared. Phosphorylated nanodiamonds were homogeneously dispersed in the polymer matrix and they displayed good compatibility. TGA results showed that the thermo-oxidative stability of PI/PNDs films was increased with the increasing amount of phosphorylated nanodiamond. (C) 2015 Society of Plastics EngineersPublication Metadata only Preparation and Characterization of Thermally Conductive Thermoplastic Polyurethane/h-BN Nanocomposites(WILEY, 2014) ÇAKMAKÇI, EMRAH; Cakmakci, Emrah; Kocyigit, Ciler; Cakir, Selma; Durmus, Ali; Kahraman, M. VezirPublication Metadata only Preparation and characterization of boron containing thiol-ene photocured hybrid coatings(ELSEVIER SCIENCE SA, 2012) ÇAKMAKÇI, EMRAH; Cakmakci, Emrah; Mulazim, Yusuf; Kahraman, Memet Vezir; Apohan, Nilhan KayamanIn this study, flame retardant, 4-vinylphenyl boronic acid containing coatings were prepared by thiol-ene polymerization. The photopolymerization kinetics of thiol-ene based formulations was investigated by real time infrared spectroscopy. The experiments showed that as the amount of boronic acid was increased, flame retardant properties of the coatings were also increased. Tensile test results showed that boronic acid groups strengthened the polymeric network. DSC results revealed that the addition of thiol causes Tg values of the coatings to decrease. On the other hand acid groups improved the hydrophilicity of the coatings. (C) 2012 Elsevier B.V. All rights reserved.Publication Metadata only Alpha-Amylase Immobilization on Epoxy Containing Thiol-Ene Photocurable Materials(KOREAN SOC MICROBIOLOGY & BIOTECHNOLOGY, 2013) ÇAKMAKÇI, EMRAH; Cakmakci, Emrah; Danis, Ozkan; Demir, Serap; Mulazim, Yusuf; Kahraman, Memet VezirThiol-ene polymerization is a versatile tool for several applications. Here we report the preparation of epoxide groups containing thiol-ene photocurable polymeric support and the covalent immobilization of alpha-amylase onto these polymeric materials. The morphology of the polymeric support was characterized by scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) coupled with SEM was used to explore the chemical composition. The polymeric support and the immobilization of the enzyme were characterized by FTIR analysis. SEM-EDS and FTIR results showed that the enzyme was successfully covalently attached to the polymeric support. The immobilization efficiency and enzyme activity of alpha-amylase were examined at various pH (5.0-8.0) and temperature (30-80 degrees C) values. The storage stability and reusability of immobilized alpha-amylase were investigated. The immobilization yield was 276 +/- 1.6 mg per gram of polymeric support. Enzyme assays demonstrated that the immobilized enzyme exhibited better thermostability than the free one. The storage stability and reusability were improved by the immobilization on this enzyme support. Free enzyme lost its activity completely within 15 days. On the other hand, the immobilized enzyme retained 86.7% of its activity after 30 days. These results confirm that alpha-amylase was successfully immobilized and gained a more stable character compared with the free one.
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