Person: ÇAKIR, MUSTAFA
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ÇAKIR
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MUSTAFA
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Publication Metadata only Synthesis and Characterization of Flexible Butadien Containing Resin for 3D SLA Printers(2022-10-15) AKIN, EMRE; ÇAKIR, MUSTAFA; Akın E., Çakır M., Berberoğlu B.As well known, epoxy acrylate resins have been widely used in 3D SLA printers applications. Epoxy acrylate system consisted of bisphenol-A glycerolate diacrylate (epoxy acrylate resin) and 1,6-Hexanediol diacrylate (HDDA, reactive diluent resin) were used in this study. The weight ratio of epoxy acrylate and HDDA was determined as 1/1. The purpose of this study is to develop a novel epoxy acrylate system for 3D SLA printers and observe its properties. For this reason, a novel urethane acrylate was synthesized as reactive resin and was added into epoxy acrylate system with various weight percents. In order to obtain this novel urethane acrylate resin, hydroxyl terminated butadien oligomer was used as backbone of the chain while isophorone diisocyanate (IPDI) and 2-Hydroxyethyl methacrylate (HEMA) were used for synthesizing urethane acrylate functional groups. The addition of this novel reactive resin was carried out up to 1.5 %. Mechanical and physical tests were applied to the produced samples such as tensile, Shore-D hardness, abrasive and density tests. Considering of the results, substantial increases were observed in terms of tensile modulus. As expected, tensile strain values presented large decreases. Shore-D hardness and densities presented slight increases. Moreover, taber abrasive resistances of the produced novel samples presented considerable increases.Publication Metadata only Characterization of carbon fiber-reinforced thermoplastic and thermosetting polyimide matrix composites manufactured by using various synthesized PI precursor resins(Elsevier Ltd, 2022) AKIN, EMRE; Çakir M., Akin E.Currently, it is important to manufacture thermoplastic advanced composites with high mechanical and thermal properties because of their higher impact resistance than thermoset composites. In this study, carbon fiber (CF)-reinforced thermoplastic and thermosetting polyimide (PI) matrix composites were manufactured by vacuum bagging followed by compression molding. Before the manufacturing process, prepregs were also prepared with various PI precursor resins by using two-step impregnation. These precursors were synthesized as poly (amic acid) (PAA), polyester amine salts (PEAS) and poly (amic acid) ammonium salts (PAAS). The PAAS precursor resin was applied as a novel method for manufacturing CF-reinforced PI matrix advanced composites. The advanced thermoplastic composite obtained from the PAAS precursor (PAAS-T) exhibited superior mechanical properties and enhanced thermal properties (near the thermal properties of thermoset advanced composites) in comparison to the other advanced composites in this study and those in the literature. However, the NA-terminated PAAS precursor (thermosetting PI precursor) did not exhibit a similar effect in terms of mechanical properties. On the other hand, the thermosetting composites exhibited highly enhanced storage modulus values up to 400 °C and outstanding thermal stability at TGA. The thermosetting composite that was obtained from the NA-terminated PAA precursor resin exhibited high mechanical properties besides its thermal properties. © 2021Publication Metadata only Urethane acrylate and silicon acrylate containing novel epoxy acrylate systems for sla 3d printers(2022-10-03) AKIN, EMRE; ÇAKIR, MUSTAFA; Çakır M., Akın E., Berberoğlu B.As well known, epoxy acrylate resins have been widely used in 3D SLA printer applications. Epoxy acrylate systems have generally consisted of bisphenol-A glycerolate diacrylate (epoxy acrylate resin) and 1,6-Hexanediol diacrylate (HDDA, reactive diluent resin) in various weight percents. The purpose of this study is to develop novel epoxy acrylate systems without HDDA and investigate their properties. For this reason, two different reactive resins were used instead of HDDA in epoxy acrylate systems with various weight percents. One of these resins was urethane acrylate resin that was synthesized in our laboratory. Urethane acrylate resin was synthesized using monomeric aliphatic diisocyanate (commercial name; Desmodur H) and 2-Hydroxymethyl methacrylate (HEMA). The other reactive resin was mixture of silicone acrylate and photoinitiator (commercial name; TEGO RC 1002). These resins were added into epoxy acrylate resin in various weight percent such as 20%, 40%, 60% and 80%. Tensile, izod impact, shore-D hardness, taber abrasive, density and DSC tests were applied to these produced samples. Considering of the results, urethane acrylate containing epoxy acrylate system exhibited much more improved results compared to pure epoxy acrylate system and silicon acrylate containing epoxy acrylate systems. It also exhibited more enhanced properties than epoxy acrylate systems with HDDA. It exhibited substantial increases in terms of tensile strength, modulus and izod impact resistance. Moreover, they presented more enhanced abrasive resistance. Shore-D hardness values and densities showed almost no change. This synthesized urethane acrylate reactive resin can be used in applications that required higher mechanical and abrasive properties for epoxy acrylate systems of 3D SLA printers.Publication Open Access Effect of Surface Modification of Fumed-Silica on Mechanical Properties of Unsaturated Polyester Composites(2015) ÇELİK, ALİ ALPARSLAN; Çakir, Mustafa; Simsek, Ramazan; Çelik, Ali AlparslanPublication Metadata only Phosphorus-containing sulfonated polyimides for proton exchange membranes(WILEY-V C H VERLAG GMBH, 2008) ÇAKIR, MUSTAFA; Cakir, Mustafa; Karatas, Sevim; Menceloglu, Yusuf; Kayaman-Apohan, Nilhan; Guengoer, AtillaSynthesis and characterization of the novel sulfonated BAPPO monomer and its use in the synthesis of a new phosphine oxide-based sulfonated polyimide are described. BTDA, 6FDA, and DDS were used as monomers in the polyimide synthesis. Sulfonated polyimide membranes were obtained by a solution thermal imidization method. The thermal behavior of the polymers was investigated by DSC and TGA. The morphological structure of the membranes was investigated by tapping-mode AFM. The proton conductivities of the sulfonated polyimide increased regularly as a function of sulfonated diamine content. The conductivities are good compared to typical proton exchange membranes.Publication Open Access Çift Kür Olabilen Hidrofob Kaplamaların Mekanik, Yüzey ve Termal Özelliklerinin İncelenmesi(2018-09-30) ÇAKIR, MUSTAFA; Mustafa ÇAKIRÖnemli kaplama teknolojilerinden biri olan ultraviyole (UV) ışıkla sertleştirme yöntemi, artan uygulama alanları ve diğer yöntemlere kıyasla var olan avantajları ile birlikte her geçen gün daha fazla tercih edilmektedir. Bu makalede, bir izosiyanat akrilat olan ICA (Laromer® LR 9000) reçinesi ile monoetilen glikol (MEG), dietilen glikol (DEG) ve hidroksil ile sonlandırılmış perfloropolieter türevi olan floro alkol (Fluorolink® E10-H) içeren reçine sistemleri kullanılarak kaplamalar hazırlanmıştır. Bu reçine sistemlerinin ısı ve UV ile sertleştirilmesi sonucunda farklı oranlarda flor içeren serbest filmler elde edilmiş ve ayrıca alüminyum levhalar üzerine de bu formülasyonlar kaplama yapılmıştır. Elde edilen serbest filmlerin; çekme testi, termogravimetrik analiz (TGA) ve diferansiyel taramalı kalorimetre (DSC) yardımıyla mekanik ve termal özellikleri belirlenmiştir. Ayrıca alüminyum levha üzerine yapılan kaplamaların özellikleri ise; kalem sertlik testi, çapraz kesme testi, parlaklık testi ve temas açısı testi ile gözlemlenmiştir. Sonuçlar incelendiğinde hidrofobik ve parlak bir kaplama elde edildiği görülmüştür. Ayrıca farklı oranlarda eklenen floro alkolün monoetilen glikol içeren yapı ile dietilen glikol içeren yapının mekanik özelliklerinde farklı etkiler yarattığı tespit edilmiştir.Publication Open Access Multi-featured epoxy composites filled with surface-modified PTFE powders treated by Na-naphthalenide system(2023-01-01) AKIN, EMRE; ÇAKIR, MUSTAFA; DEMİRER, HALİL; AKIN E., ÇAKIR M., DEMİRER H.This study aimed to produce new multi-featured epoxy composites that are advanced in terms of mechanical properties, wear and impact resistance, and glass transition and heat deflection temperatures. Epoxy composites filled with chemically surface-treated poly (tetrafluoroethylene) (PTFE) powders at various ratios were prepared to obtain these improved properties. The chemical treatment was carried out via a Na-naphthalenide system. After this treatment, the x-ray photoelectron spectroscopy results presented the existence of functional groups such as OH, carbonyl groups, and C=C unsaturation points on the surface of the PTFE powders. On the PTFE surfaces, while the atomic ratios of carbon and oxygen were substantially increased, the fluorine ratio presented a significant decrease after the chemical treatment. However, the wear rates of the novel composites were highly advanced despite this large decrease in the fluorine ratio on the surface of the PTFE powders. Moreover, functional groups such as OH, carbonyl groups, and C=C unsaturation points and spongelike or network structures on the PTFE surfaces provided the opportunity to obtain strong adhesion and interfacial bonding between the surface-modified PTFE powders and the matrix. Strength and modulus values showed substantial enhancement besides the IZOD impact resistance. All glass transition and heat deflection temperatures were also substantially improved.Publication Metadata only Synthesis and characterization of flexible polydimethylsiloxane containing resin for 3D SLA printers(2021-10-15) ÇAKIR, MUSTAFA; AKIN, EMRE; Akın E., Çakır M., Berberoğlu B.As well known, epoxy acrylate resins has been widely used in 3D SLA printers applications. Epoxy acrylate system that consisted of bisphenol-A glycerolate diacrylate (epoxy acrylate resin) and 1,6-Hexanediol diacrylate ( HDDA, reactive diluent resin) were used in this study. The weight ratio of Bisphenol-A glycerolate diacrylate and HDDA was determined as 1/1. The purpose of this study is to develop a novel epoxy acrylate system for 3D SLA printers and observe its properties. For this reason, a novel polydimethylsiloxane containing urethane acrylate was synthesized as reactive resin and added into epoxy acrylate system with various weight percents. It is also well known that polydimethylsiloxanes increase thermal properties of polymer materials. In order to obtain this novel reactice urethane acrylate resin, hydroxyl terminated polydimethylsiloxane was used as backbone of the chain while isophorone diisocyanate (IPDI) and 2-Hydroxyethyl methacrylate (HEMA) were used for synthesizing urethane acrylate functional groups. The addition of this novel reactive resin was carried out up to 1.5 % into epoxy acrylate system. Mechanical and physical tests were applied to the produced samples such as tensile, Shore-D hardness, abrasive and density tests. Considering of the results, tensile strength and modulus exhibited substantial increases while tensile strain presented large decreases. Taber abrasive resistance showed considerable increases. While Shore-D hardness of the produced novel materials presented slight decreases, the densities showed almost no changePublication Metadata only Magnetic and microwave absorption properties of PVB/Fe3O4 and PVB/NiFe2O4 composites(WILEY, 2018) AKIN, EMRE; Akinay, Yuksel; Hayat, Fatih; Cakir, Mustafa; Akin, EmreElectromagnetic and microwave absorbing properties of Polyvinylbutyral (PVB)/Fe3O4 and PVB/NiFe2O4 composites were investigated in the 1-14 GHz. PVB/filler particles (Fe3O4 and NiFe2O4) composites were prepared with 90/10 mixture ratios via Ultrasonic Probe Sonicator method in solution. The complex permittivity (epsilon-j epsilon) and permeability (- j) of the composites have been measured at different microwave frequencies in 1-14 GHz employing vector network analyzer (Keysight N9926A). The reflection loss (R-L) of composites was calculated and evaluated using theory of the absorbing wall. It was found that, both composites exhibit the large reflection loss and broadband within the frequency range from 1 to 14 GHz for 3, 5, and 7 mm. However, the R-L results show that, when the thickness is 7 mm, the minimum R-L was found to be -22.9 dB (99% power absorption) at the frequency of 13.93 GHz. The Fe3O4/PVB and NiFe2O4/PVB composites have potential application for microwave and radar absorptions. POLYM. COMPOS., 39:3418-3423, 2018. (c) 2017 Society of Plastics EngineersPublication Metadata only Thermal and surface properties of a novel hybrid polyimide containing fluorine chains(2016-11-25) ÇAKIR, MUSTAFA; AKIN E., ÇAKIR M., AKINAY Y.
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