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Öğe Atık lastik tozuna uygulanan yüzey işlemleri ve atık lastik tozunun polimer/orijinal kauçuk bileşimlerinde kullanımının incelenmesi(Niğde Ömer Halisdemir Üniversitesi, 2024) Erzincanlı, İlker; Karabörk, FazliyeAtık taşıt lastikleri malzemesi ve miktarı bakımından son derece değerli bir atık formudur. Atık lastiklerin geri kazanımında henüz sürdürülebilir ve verimli bir teknoloji geliştirilemediği için bu atığın değerlendirilmesi konusunda araştırmacılar çeşitli uygulamalara yönelmişlerdir. Bunlar arasında atık lastik tozlarının çeşitli malzeme bileşimlerine katılarak değerlendirilmesi önemli bir yer tutmaktadır. Bu uygulamalarda atık kauçuk tozunun katıldığı malzeme ile uyumunun kauçuğun yapısı gereği yeterince sağlanamadığı, bunun sonucunda malzeme özelliklerinin olumsuz etkilendiği görülmüştür. Kauçuk tozuna uygulanacak çeşitli yüzey işlemlerinin (yüzey modifikasyonu ve yüzey devulkanizasyonu) kauçuk tozu/matris uyumunu arttırdığına yönelik araştırmalar yoğun olarak sürdürülmektedir. Bu çalışmada, kauçuk tozuna uygulanan yüzey işlemleri detaylı olarak ele alınmış ve konuyla ilgili yapılan literatür çalışmaları incelenmiştir. Yapılan araştırmalar, kauçuk tozuna uygulanan yüzey işlemlerinin, tozun içine katıldığı malzeme ile uyumunu arttırdığını ortaya koymaktadır.Öğe Characterization of styrene butadiene rubber and microwave devulcanized ground tire rubber composites(Walter de Gruyter GmbH, 2014) Karabörk, Fazliye; Pehlivan, Erol; Akdemir, AhmetGround tire rubber (GTR) was devulcanized by microwaves at the same heating rate (constant power) and different times of exposure. The devulcanized rubber (DVR) and untreated GTR were characterized physically and thermally. Composite materials were prepared from different proportions of the GTR, which was used as a filler, and the DV-R, which was used as part of the styrene butadiene rubber (SBR) matrix, and by varying the exposure time of the microwave power. These composites were compared with a control sample that was prepared from virgin SBR. The sol content (soluble part) and Fourier transform infrared spectroscopy (FTIR) analyses of the devulcanized samples were examined to define the efficiency of devulcanization. The cure characteristics and tensile properties of the SBR composites were researched. In this study, it was found that using DV-R as part of the rubber matrix produced much better properties than using GTR as a filler, thereby showing the significant benefits of microwave devulcanization. At the DV-R content of 50 phr, the elongation at break of the DV-R 5 min/SBR composites increased to 445.06% from 217.25% for the GTR/SBR composites, i.e., the elongation at break was enhanced by 105% by the devulcanization of GTR. Scanning electron microscopy (SEM) photographs displayed a better interface coherence between the DV-R 5 min and SBR matrix than the GTR/SBR composites.Öğe Effect of Silica/Graphene nanohybrid particles on the mechanical properties of epoxy coatings(Springer Berlin Heidelberg, 2019) Özcan, Ümit Esra; Yazman, Şakir; Akdemir, Ahmet; Karabörk, FazliyeEpoxy resins are used as coating materials, but the practical use of epoxy coatings in industries is limited due to their weak mechanical properties. In the present paper, different amounts of silica nanoparticles ( SiO2) and graphene nanoplatelets (GNPs) were introduced separately and together into an epoxy coating matrix as reinforcements. Graphene, a newly discovered carbon allotrope, has been found to improve the mechanical properties of the polymer composites in which it is dispersed. Silica particles are also known to improve the mechanical properties of composites. In this study, mechanical, physical and thermal properties of the epoxy coatings are considered as multidimensional by the macro- and microanalyses. The experimental results showed that after the addition of GNPs into the epoxy matrix, the flexibility and impact resistance of the coatings increased by 8.3 and 157.1%, respectively, in relation to neat epoxy. The microhardness increased by 53.8% and penetration depth, which is indicative of the scratch resistance, decreased by 29.7%, with the addition of SiO2 –GNPs nanohybrid. A remarkable synergistic effect was observed between the GNPs and SiO2 , which improved the hardness and the scratch resistance of the epoxy coatings.Öğe Effects of nano reinforcing/matrix interaction on chemical, thermal and mechanical properties of epoxy nanocomposites(SAGE Publications Ltd, 2021) Yazman, Şakir; Uyaner, Mesut; Karabörk, Fazliye; Akdemir, AhmetThis article investigates the impact of addition various types of nanoparticles with different structural, dimensional, and morphological properties on the interphase region formed between the particle/matrix and the curing behavior of the epoxy affect the nanocomposite material properties. For this purpose, epoxy nanocomposites (NCs) were produced by adding multi-walled carbon nanotube (MWCNT) and alumina (Al2O3) nanoparticles (NPs) into the epoxy matrix at different rates (0.5–2.0 wt.%). The effects of the particle/matrix interaction on the properties of the composite have been revealed by chemical, thermal, mechanical analyzes and microstructure investigations. An increase in the absorption density, which reveals the physical interaction of nanoparticles with the epoxy matrix, was observed in Fourier-transform infrared spectroscopy. Absorption vibration peak intensities in nanocomposite samples were at most 1.0 wt.% Al2O3 and 1.25 wt.% CNT added nanocomposites. It was observed that the Tg value increased depending on the number of nanoparticles. The addition of Al2O3 increased Tg values more than CNT. Besides, the mechanical properties of NCs were determined by tensile tests. The highest increase in mechanical properties was achieved by adding 1.25 wt.% CNT and 1.0 wt.% Al2O3, respectively. Mechanical properties tended to decrease at higher addition rates. The shape, size, amount, and distribution of nanoparticles added into the epoxy matrix directly affected the NCs' properties. It has been determined that homogeneously dispersed spherical Al2O3 nanoparticles are more effective than fiber-shaped CNTs in the properties of NCs.Öğe Farklı oranlarda DPDS kullanılarak devulkanize edilmiş atık taşıt lastikleri ilave edilen SBR malzemenin mekanik özelliklerinin incelenmesi(Pamukkale Üniversitesi, 2015) Karabörk, Fazliye; Akdemir, AhmetOda sıcaklığında öğütülen atık taşıt lastiği tozu mikrodalga yöntemiyle devulkanize edilmiştir. İşlemde devulkanizasyon ajanı olarak, kükürt bağlarının (S-S) koparılmasında etkinliği çeşitli çalışmalarda ortaya konulmuş olan, DPDS (difenildisülfür) kullanılmıştır. Mikrodalga gücü sabit tutularak, zamanın ve DPDS miktarının prosese etkileri incelenmiştir. İşlem görmemiş atık lastik tozu fiziksel ve termal olarak karakterize edilmiştir. 20 phr oranında atık lastik tozu ve aynı oranda devulkanize kauçuk (DVR) stiren bütadien kauçuğa (SBR 1723 ve SBR 1502) katılarak kompozit malzemeler hazırlanmıştır. Bu kompozitler orijinal SBR'den hazırlanan kontrol numunesiyle karşılaştırılmıştır. Devulkanizasyonun etkinliğini ortaya koyabilmek için devulkanize numunelerin çözünme oranları (sol content) belirlenmiş ve Fourier Transform Infrared Spektrofotometre (FTIR) analizi yapılmıştır. Elde edilen kompozit malzemelerin mekanik özellikleri incelenmiştir. Çalışmada, DVR katılan malzemelerde atık lastik tozu katılan malzemelere göre daha iyi devulkanizasyonunun önemli avantajlar sağladığını göstermiştir. Kopma uzaması değeri, işlem görmemiş atık lastik tozu katılan kompozit malzemede %481 iken, 1 g DPDS katılarak 4 dk. süreyle devulkanize edilen kauçuğun katıldığı DVR/SBR kompozitte %578 olarak elde edilmiştir, böylece kopma uzaması değeri atık lastik tozunun devulkanizasyonuyla %20 oranında artmıştır.Öğe Improvement of anti-corrosion performance (surface and near the cut edge) and mechanical properties of epoxy coatings modified with nano, micro and hybrid ZnO particles(SAGE Publications Ltd, 2023) Kabaoğlu, Emre; Karabörk, Fazliye; Balun Kayan, Didem; Akdemir, AhmetComposites were formed by incorporating nano, micro and hybrid-ZnO particles into the epoxy matrix at the same loading levels (3%) and applied at 90 ?m thickness on the galvanized steel substrate using a film applicator in this study. The improvement in anti-corrosion performance and mechanical and physical properties of the composite coatings were evaluated using various tests and techniques such as salt-spray, electrochemical impedance spectroscopy, nanohardness, microscratch, cross-cut, bending, Fourier transform infrared spectroscopy, thermogravimetric and Scanning electron microscopy. The corrosion performance of the composite coatings near the cut edge is discussed in detail as well as on the surface of galvanized steel. The results show that the addition of all ZnO particles has a positive effect on the corrosion resistance and mechanical properties of the coatings. The addition of nano, micro and hybrid ZnO particles increased the hardness of the composites by 52, 37 and 56%, respectively, compared to the neat epoxy. Although the cathodic protection performance is weakened near the cut edge due to the loss of Zn after thermal cutting, high barrier protection was provided with composite coatings, especially micro ZnO/Epoxy composite coating.Öğe Influence of pyrolytic carbon black and pyrolytic oil made from used tires on the curing and (dynamic) mechanical properties of natural rubber (NR)/styrene-butadiene rubber (SBR) blends(BME-PT and GTE, 2016) Karabörk, Fazliye; Tıpırdamaz, SeherPyrolytic carbon black (CBp) and pyrolytic oil (Op) made from used tires were used in natural rubber (NR)/ styrene-butadiene rubber (SBR) blends. The effects of CBp and Op on the processing properties, the mechanical properties and the dynamic mechanical properties of the NR/SBR blends were investigated and compared with a control sample that was prepared with N550 and commercial process oil. It was found that the effect of CBp on the processing properties of the NR/SBR blends was similar to that of N550. With the increase of the CBp content, the curing properties of the NR/SBR blends changed little. The reinforcing effect of CBp was inferior to that of N550. With the increase of the CBp content, the tensile strength, tear strength and modulus at 100% elongation of the NR/SBR vulcanizates decreased significantly. Dynamic mechanical properties of the NR/SBR blends were also affected and all samples comprising CBp have a higher tan ! than control sample. It is suggested that the low surface area and high ash content of CBp strongly effects all of these property changes of the NR/SBR blends. The morphology and distribution of the carbon black particles are studied using a scanning electron microscope. It was also found that with the increase of the Op content, the properties of the NR/SBR blends were strongly affected due to the high sulfur content of Op, which produced a high crosslinking density.Öğe Investigation effect of zinc nanoparticles on the mechanical and anticorrosion properties of epoxy coatings on stainless steel surface(Gazi Üniversitesi, 2021) Apsak, Merve; Akdemir, Ahmet; Karabörk, Fazliye; Yazman, ŞakirIn this study, effects of zinc nanoparticles (ZNPs) on the mechanical properties of epoxy coatings and anticorrosion behavior on the stainless steel were investigated. The nanocomposites (NCs) were obtained by adding ZNPs (0.5, 1.0, 1.5 wt%) to epoxy resin. The first stage in this study, bulk samples were prepared for tensile test and DSC, TGA, FTIR, SEM analysis. The test and analysis were performed separately for samples cured at room temperature for 24 h and postcured at 80 degrees C for 15 h in the oven. The results indicated that both postcuring and adding ZNPs caused an increase in the mechanical properties of the epoxy matrix. Tensile strength increased by 13.2% and 90.2% in the postcured NC (1.0% Zn) and untreated NC (0.5% Zn) respectively. The NCs prepared with the same parameters for the second stage were coated on AISI 304 test panels and the panels were postcured in the oven. The anticorrosive performance of the coatings was studied by an immersion test. According to the corrosion test results, it was observed that the coated steel surface preserves the best rate of 1.0% ZNPs containing epoxy composite. In addition, impact resistance, flexibilities and adhesion properties of the coating were analyzed.Öğe Investigation of mechanical properties of SBR in which added devulcanized waste tire rubber with various proportions of DPDS(Pamukkale University, 2015) Karabörk, Fazliye; Akdemir, AhmetThe waste tire rubber that had been grounded in room temperature was devulcanized by using the microwave method. As the devulcanizing agent, diphenyldisulfide (DPDS), the efficiency of which in the breaking off of sulfur bonds (S-S) had been proven in various studies, was employed. By maintaining the microwave power at a fixed value, the effects of time and the DPDS amount on the process were investigated. The untreated waste tire rubber powder was characterized physically and thermally. Composite materials were prepared with 20 phr untreated waste tire rubber powder and devulcanized rubber (DVR) with the styrene butadiene rubber (SBR) matrix. These composites were compared with a control sample that was prepared from virgin SBR. The sol content (soluble part) and Fourier Transform Infrared Spectrophotometer (FTIR) analyses of the devulcanized samples have been examined to define the efficiency of devulcanization. The mechanical properties of the SBR composites were researched. In this study, it was found that using devulcanized rubber produced much better properties than using waste tire rubber powder, thereby showing the significant benefits of microwave devulcanization. At the DPDS content of 1 g, the elongation at break of the DVR 4 min/SBR composites increased to 578% from 481% for the untreated waste tire rubber powder and SBR composites, the elongation at break was enhanced by 20% by the devulcanization of waste tire rubber powder.Öğe Investigation of the mechanical, tribological and corrosive properties of epoxy composite coatings reinforced with recycled waste tire products(BME-PT and GTE, 2022) Karabörk, FazliyeReaxys Chemistry database information Indexed keywords SciVal Topics Metrics Abstract The present work aims at evaluating the mechanical and anti-corrosion behaviour of epoxy coatings modified by recycled waste tire products. In this study, the epoxy coatings reinforced with ground tire rubber (GTR), devulcanised ground tire rubber (DGTR), pyrolytic carbon black (PCB) and original carbon black (CB) particle contents were prepared and applied to the galvanised steel substrate. Micro-mechanical tests (nanohardness and microscratch) were used to measure the mechanical properties of the coatings. Tribological and corrosive performance of the coatings were evaluated using reciprocating ball-on disc test and salt spray corrosion test (5 wt% NaCl), respectively. The experimental results showed that the recycled waste tire products reinforced composite coatings significantly improved resistance to wear and corrosion inhibition property. In the study, the most remarkable results were the increase in wear resistance by 77.7% in the coating strengthened with DGTR.Öğe Nano çinko oksit partikül katılan epoksi kaplamaların mekanik ve antikorozif özelliklerinin incelenmesi(Uludağ Üniversitesi, 2023) Askerden, Mehmet Kubilay; Akdemir, Ahmet; Karabörk, Fazliye; Yazman, ŞakirBu çalışmada, metal yüzeyleri korumak amacıyla kullanılan epoksi kaplamaya katılan ZnO nanopartiküllerin kaplamanın mekanik ve antikorozif özellikleri üzerindeki etkisi araştırılmıştır. Çalışma iki aşamada gerçekleştirilmiştir. İlk aşamada hem katılacak partikül miktarını belirleyerek kompozit malzemeyi üretmek hem de bu malzemenin özelliklerini belirlemek için çalışmalar yapılmıştır. Deneysel çalışmalar sonucunda epoksi matrise ağ. %0,5, 1 ve 1,5 oranlarında nano ZnO katılmasına karar verilmiştir. Bu oranlarla hazırlanan kompozit malzemelere uygulanan çekme testi sonunda en yüksek özellikler ağ. %1 ZnO nanopartikül katılan kompozit malzemede elde edilmiştir. Nanokompozitlerin diğer özelliklerini belirlemek amacıyla ayrıca; DSC, TGA, FTIR, SEM analizleri yapılmıştır. İkinci aşamada hazırlanan nanokompozitler çelik test plakaları üzerine kaplanmıştır. Kaplamaların antikorozif performansı asit çözeltisine daldırma ve tuz sisi testleri ile incelenmiştir. Korozyon testi sonuçlarına göre, en iyi sonuç %1 ZnO nanopartikül katılan kompozit kaplamada elde edilmiştir. Ayrıca kaplamaların darbe dayanımı, esnekliği ve çelik alt tabakaya yapışma özellikleri çeşitli testlerle incelenmiştir.Öğe Tel haddeleme tekniği ile Cu/Mgb2 süper iletken tellerin üretimi ve üretim parametrelerinin ürün özelliklerine etkilerinin incelenmesi(TÜBİTAK MAG Proje, 2015) Cengil, Mehmet; Nair, Fehmi; Karabörk, FazliyeBu projede, tüp içerisinde toz (Powder in Tube, PIT) yöntemi ile hazırlanmış Cu/MgB2 kompozit yapıların, tel haddeleme tekniği kullanılarak süper iletken tellere dönüştürülmesi ve üretim parametrelerinin ürün özelliklerine etkisi araştırılmıştır. Bu amaçla, farklı çaplarda (min. 0.55 mm) tek ve çok özlü teller, bariyer malzemesi kullanılmadan ve kullanılarak üretilmiştir. Farklı geometrilerdeki bu tellerin üretimi, bakır tüp içerisine açılan deliğe MgB2 tozlarının doldurulmasıyla hazırlanan kompozit biletlerin ekstrüzyonuyla üretilen filmaşinler veya doğrudan bu kompozit biletler kullanılarak, haddeleme işlemi ile yapılmıştır. Haddeleme öncesi üretim aşamalarında, malzmenin plastik deformasyon kabiliyetinin arttırılması ve ürün özelliklerinin bozulmaması için, gerek görülen durumlarda ara tavlamalar yapılmıştır.
