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Öğe Aerosol filtration performance of nanofibrous mats produced via electrically assisted industrial-scale solution blowing(Wiley, 2021) Gungor, Melike; Toptas, Ali; Calisir, Mehmet Durmus; Kilic, AliHighly efficient polyamide 6 (PA6)-based nanofibrous air filter media was developed for particulate matter (PM) removal in the ambient atmosphere. The PA6 nanofibrous mats exhibited 85% PM0.3 capture performance at a cost of 164 Pa pressure drop when the multiple-nozzle solution blowing system was set to 8 m/h fabric winding speed. However, an increase in the winding speed at a constant feeding rate lowered the filtration efficiency to 62% due to the less amount of nanofibrous mats collected on the substrate. The application of electrical field at the same parameters allowed us to produce a filter media having FFP3-level filtration performance, which means 99% PM0.3 capture performance. This was attributed to a fine fiber diameter (116 nm), higher solidity value (0.149), and lower average pore size (2.28 mu m). These results show that the electrically assisted solution blowing provides a feasible route for the production of high-quality nanofibrous filter media.Öğe Aerosol Filtration Performance of Solution Blown PA6 Webs with Bimodal Fiber Distribution(Amer Chemical Soc, 2022) Gungor, Melike; Selcuk, Sule; Toptas, Ali; Kilic, AliA bimodal web, where both nanofibers and microfibers are present and distributed randomly across the same web, can deliver high filter efficiency and low pressure drop at the same time since in such a web, filter efficiency is high thanks to small pores created by the presence of nanofibers and the interfiber space created by the presence of microfibers, which is large enough for air to flow through with little resistance. In this work, a bimodal polyamide 6 (PA6) filter web was fabricated via a modified solution blowing (m-SB) technique that produced nanofibers and microfibers simultaneously. Scanning electron microscope (SEM) images of the webs were used to analyze the fiber morphology. Additionally, air permeability, solidity, porosity, filtration performance, and tensile strength of the samples were measured. The bimodal filter web consisted of nanofibers and microfibers with average diameters of 81.5 +/- 127 nm and 1.6 +/- 0.458 mu m, respectively. Its filter efficiency, pressure drop at 95 L min-1, and tensile strength were 98.891%, 168 Pa, and 0.1 MPa, respectively. Its quality factor (QF) and tensile strength were 0.0268 Pa-1 and 0.1 MPa, respectively. When compared with commercially available filters, the bimodal web produced had superior filter performance, constituting a suitable alternative for air filter applications.Öğe Biodegradable Biconstituent Melt-Blown Nonwovens for Air Filtration: Fabrication and Characterization(Korean Fiber Soc, 2024) Eticha, Andinet Kumella; Akgul, Yasin; Pakolpakcil, Ayben; Unlu, Oguz Kagan; Ahmed, Salih Birhanu; Cug, Harun; Kilic, AliMelt-blown polypropylene (PP) is extensively used in air filtration due to its low cost, low weight, and easy processing, but there are increasing environmental concerns due to its non-degradability. On the other side biodegradable polymers such as polylactic acid (PLA) present insufficient strength and limited toughness. Polymer blending is a well-known approach to reach optimum properties from at least two polymers. This study aims to produce biodegradable PP-PLA-based filter materials that possess enhanced elasticity and superior filtration performance. The addition of PLA raises the average fiber diameter (AFD), causing the PP-PLA filters to have AFD ranging from 0.73 to 0.91 mu m. However, the incorporation of zinc stearate (ZnSt) decreased the melt viscosity, resulting in thinner fiber formations with AFD ranging from 0.6 to 0.75 mu m for PP-PLA-ZnSt. The efficiency of the corona-charged optimized sample (double-layer 75PP-25PLA-ZnSt) showed 97.42% particle capture efficiency and filtration performance of 0.12 mmH(2)O(-1). Despite the presence of hydrophobic surfaces in all filter materials, the addition of ZnSt further improves the resistance to surface wettability. 75PP-25PLA-ZnSt filter material exhibits high stretchability, with a maximum tensile strength of 380 +/- 70 kPa. The proposed tricomponent (PP-PLA-ZnSt) approach would be used to reduce the environmental impact of non-degrading polymers.Öğe Centrifugally spun hydroxyapatite/carbon composite nanofiber scaffolds for bone tissue engineering(Iop Publishing Ltd, 2024) Akgul, Yasin; Stojanovska, Elena; Calisir, Mehmet Durmus; Polat, Yusuf; Kilic, AliIn recent years, advancements in tissue engineering have demonstrated the potential to expedite bone matrix formation, leading to shorter recovery times and decreased clinical challenges compared to conventional methods. Therefore, this study aims to develop composite carbon nanofibers (CNFs) integrated with nano-hydroxyapatite (nHA) particles as scaffolds for bone tissue engineering applications. A key strategy in achieving this objective involves harnessing nanofibrous structures, which offer a high surface area, coupled with nHA particles expected to accelerate bone regeneration and enhance biological activity. To realize this, polyacrylonitrile (PAN)/nHA nanofibers were fabricated using the centrifugal spinning (C-Spin) technique and subsequently carbonized to yield CNF/nHA composite structures. Scanning Electron Microscopy (SEM) confirmed C-Spin as a suitable method for PAN and CNF nanofiber production, with nHA particles uniformly dispersed throughout the nanofibrous structure. Carbonization resulted in reduced fiber diameter due to thermal decomposition and shrinkage of PAN molecules during the process. Furthermore, the incorporation of nHA particles into PAN lowered the stabilization temperature (by 5 degrees C-20 degrees C). Tensile tests revealed that PAN samples experienced an approximately 80% increase in ultimate tensile strength and a 187% increase in modulus with a 5 wt.% nHA loading. However, following carbonization, CNF samples exhibited a 50% decrease in strength compared to PAN samples. Additionally, the addition of nHA into CNF improved the graphitic structure. The incorporation of nHA particles into the spinning solution represents a viable strategy for enhancing CNF bioactivity.Öğe Centrifugally spun silica (SiO2) nanofibers for high-temperature air filtration(Taylor & Francis Inc, 2019) Tepekiran, Beyza Nur; Calisir, Mehmet D.; Polat, Yusuf; Akgul, Yasin; Kilic, AliIn this study, silica-based nanofibers were produced via centrifugal spinning (C-spin) and subsequent calcination. The produced heat resistant media was challenged with NaCl nanoparticles to investigate their filtration performance. To obtain inorganic SiO2 nanofibers, C-spun organic PVP-TEOS nanofibers were calcinated at 300-600 degrees C. Effects of solution concentration and calcination temperature on crystallinity, morphology and air filtration performance of nanofibers were investigated. Scanning electron microscopy (SEM) analysis was performed to analyze fiber diameter and morphology of nanofibrous webs. Differential thermal analysis (DTA) was realized for the thermal behavior of samples. Moreover, X-ray diffraction (XRD) and Fourier transform infrared spectra (FTIR) analysis were realized for further characterization. In addition to the chemical and morphological analysis, the ductility of the samples was investigated via tensile tests. Finally, calcinated webs were challenged with 0.4 mu m salt particles to analyze their filtration performance. The calcinated 5 wt% TEOS/PVP silica nanofiber webs were more brittle due to three times lower precursor content. Therefore, flexibility (percent elongation) of 15 wt%TEOS/PVP sample was nearly five times higher than 5 wt%TEOS/PVP sample. The calcinated 15 wt%TEOS/PVP sample showed the highest filtration performance among all the silica nanofibers. The average fiber diameter of the optimized web was found to be the lowest, which is around 521 +/- 308 nm, which resulted in enhanced filtration efficiency around 75.89%. Copyright (c) 2019 American Association for Aerosol ResearchÖğe Characterization of solution blown thermoplastic polyurethane nanofibers modified with Szygium aromaticum extract(Taylor & Francis Ltd, 2020) Canbay-Gokce, Emine; Akgul, Yasin; Gokce, Ahmet Yakup; Tasdelen-Yucedag, Cigdem; Kilic, Ali; Hassanin, AhmedAntibacterial wound dressing mats were produced via coating solution blown TPU nanofiber mats with Szygium aromaticum extract (clove oil). Soxhlet extraction was used to obtain clove oil (CO) and according to gas chromatography-mass spectrometry analysis, it was shown that extract was mostly composed of eugenol and beta-caryophylene, which exhibit superior antimicrobial activity. TPU nanofiber mats were coated with obtained clove oil in order to obtain antibacterial nanofibers. Even 2 mg/cm(2) clove oil coated TPU nanofibers (E2/TPU) exhibited a zone of inhibition around 24 and 22 mm against S. aureus and E. coli, respectively. On the other hand, air permeability of nanofibrous mats decreased with the increasing amount of clove oil over 5 mg/cm(2), because clove oil caused changes in nanofiber morphology. However, the presence of clove oil did not affect the morphology of E2/TPU, where air permeability values of those dressings were close to that of neat TPU nanofiber mats.Öğe Clogging performance of micro/nanofibrous laminated composite air filter media(Sage Publications Inc, 2022) Calisir, Mehmet D.; Gungor, Melike; Toptas, Ali; Donmez, Utkay; Kilic, Ali; Karabuga, SemistanThe performance of fibrous filter media relies on factors such as particle capture efficiency, pressure drop and clogging time. Fiber diameter, porosity and packing density are important web-based factors to improve final filtration performance. In this study, composite nonwoven webs were produced using spunbonded, meltblown and electroblown mats to obtain filter media with different fiber diameter, porosity and packing density. Such a layered composite approach caused huge differences in porosity and packing density, which resulted with improved clogging performance. The average fiber diameter was found to be 65 +/- 19.4 nm for electroblown layer (N), while that was 1.17 +/- 0.38 mu m for meltblown (M) and 17.64 +/- 2.65 mu m for spunbond (S) layers. NM (nanofiber+meltblown) configuration provided 12-13% lower mean flow pore size, which resulted in faster clogging compared to NS (nanofiber + spunbond) mats. The thicker nanofibrous layer resulted in lower pore size and quality factor. Additionally, the composite samples showed a faster-rising pressure drop than the thick microfibrous mats due to smaller pores that clogged quickly. It was also shown that nanofiber coating causes a linear increase in pressure drop with dust loading, while microfibrous samples exhibited smooth plateau and linear increase after clogging point. Nanofiber layer facilitates cake formation which causes more difficult airflow, and lower dust holding capacity. Among the layered composite mats, the NM configurations were found to be more advantageous due to higher initial filtration efficiency and almost similar dust loading performance.Öğe Electrically assisted solution blow spinning of PVDF/TPU nanofibrous mats for air filtration applications(Tubitak Scientific & Technological Research Council Turkey, 2023) Eticha, Andinet Kumella; Toptas, Ali; Akgul, Yasin; Kilic, AliIn this study, pure polyvinylidene fluoride (PVDF), pure thermoplastic polyurethane (TPU), and PVDF/TPU blend nanofibers (1:3, 2:2, 3:1 ratios) were produced via electrically assisted solution blow spinning for air filtration applications. Scanning electron microscopy (SEM) analysis was conducted to investigate the diameters and morphology of nanofibers. The filtration performance of nanofibrous mats was examined by air filtration test with challenging with 0.26 +/- 0.07 mu m salt particles. Moreover, the flexibility and strength of the samples were determined via tensile tests. Results showed that pure TPU nanofibers had better mechanical properties, while pure PVDF nanofibers showed better filtration performance. However, 3PVDF/1TPU nanofibrous sample had high filtration efficiency (98.86%) close to pure PVDF (99.85%) and better flexibility (32.80% elongation) compared to pure PVDF (11.64% elongation).Öğe Enhancing filtration performance of submicron particle filter media through bimodal structural design(Wiley, 2024) Toptas, Ali; Calisir, Mehmet D.; Gungor, Melike; Kilic, AliDepth filtration is a widely utilized mechanism for submicron aerosol filtration using disposable filter cartridges and facemasks. The filter media should be carefully engineered to reach high filtration efficiency and dust-loading capacity at the expense of a low-pressure drop (Delta P). Filter media with bimodal fiber diameter distribution enhance particle capture by creating small pores with tiny fibers, while microfibers improve airflow, reduce Delta P, and increase the effective filter area for particle retention. In this study, bimodal filters were achieved through the homogeneous distribution or layered use of nanofibers and microfibers. The impact of the bimodal design was explored using fibrous mats produced through melt-blowing, solution-blowing, and electroblowing methods. Keeping the basis weight of filter samples at 30 gsm, using four-layered filters (4L) improved air permeability compared to single-layer samples. The 4L sample exhibited the highest performance, achieving 99.52% efficiency at 148 Pa. Moreover, replacing the melt-blown layer with bimodal mats in the 4L design increased the filtration efficiency to 99.61% keeping Delta P nearly the same. The corona discharge treatment yielded the highest efficiency (99.99%) in the 4BML sample, even after 1 month the efficiency was maintained at 99.90%, highlighting the advantage of bimodal fiber distribution in electret filters.HighlightsFour-layered filter (4L) structures resulted in improved air permeability.Bimodal layer (BL) achieved by adding SB nanofibers into the melt blowing.BL in 4L structure increased the efficiency from 99.52% to 99.61%.Modified BL sample (4BML) provides the highest QF (0.044 Pa-1) after 1 month. Production of the layered bimodal mats in different structural designs and their filtration performance.imageÖğe Fabrication of stretchable and high-filtration performance melt-blown nonwoven webs for PM0.3 aerosol filtration(Wiley, 2024) Eticha, Andinet Kumella; Akgul, Yasin; Pakolpakcil, Ayben; Unlu, Oguz Kagan; Cug, Harun; Kilic, AliPolypropylene (PP) is a semi-crystalline polymer that displays simple manufacturing, high stiffness, lightweight, chemical resistance, and inexpensive. However, PP has significant drawbacks, such as poor brittleness at low temperatures, high shrinkage ratio, and low impact resistance, which limit its development. Thermoplastic polyurethane (TPU) possesses recyclable and eco-friendly characteristics, along with the elasticity of rubber and exceptional mechanical properties. In this study, a flexible and high-filtration performance PP-TPU textile material was developed by melt-blowing for filtering PM0.3 aerosols. For the first time, a melt-blown PP-TPU nonwoven was used as an air filter. The fiber morphological studies exhibited that addition of 10 and 20 wt.% TPU into PP resulted in a fiber diameter increment from 0.94 to 1.24 mu m. Also, melt-blown PP-TPU forms helical fibers, which are different from fibers noticed in melt-blown PP. Corona-charged double-layer 80PP-20TPU nonwovens have a filtration efficiency of 99.25% and quality factor (QF) of 0.13 mm H2O-1 at an air flow rate of 95 L/min. Moreover, PP's tensile strength was increased by 72.22%, and elongation was raised by 38.1% with the addition of 20 wt.% TPU. Thus, PP-TPU melt-blown composites may bring novel perspectives into the design and development of high-performance filtering materials for a variety of applications.Öğe Fabrication ofco-PVDF/modacrylic/SiO2nanofibrous membrane: Composite separator for safe and high performance lithium-ion batteries(Wiley, 2021) Al Rai, Adel; Stojanovska, Elena; Akgul, Yasin; Khan, Mohammad Mansoob; Kilic, Ali; Yilmaz, SafakHighly porous free-standing co-poly(vinylidene fluoride)/modacrylic/SiO(2)nanofibrous membrane was developed using electrically-assisted solution blow spinning method. The performance and the potential of the membrane as a lithium-ion battery separator were investigated. The addition of modacrylic enhanced the solution spinnability that resulted in defect-free membranes. Moreover, the presence of modacrylic enhanced the dimensional and thermal stabilities, while the addition of hydrophilic SiO2 nanoparticle enhanced both mechanical property and ionic conductivity. Combustion test results illustrated that the presence of modacrylic provide flame retarding property over a set of different polymeric-based membranes. Electrochemical performance results showed that the developed membrane can increase the battery capacity compared with the commercial separator.Öğe Influence of carbon fiber content on bio-tribological performances of high-density polyethylene(Iop Publishing Ltd, 2019) Akgul, Yasin; Ahlatci, Hayrettin; Turan, Muhammet Emre; Erden, Mehmet Akif; Sun, Yavuz; Kilic, AliThe present study aims to investigate the effect of short carbon fiber (SCFs) content on wear performance of high-density polyethylene (HDPE). SCFs reinforced composites with different weight fractions (5 wt%, 10 wt%, 15 wt% and 20 wt%) were fabricated by melt compounding and compression molding. To evaluate bio- tribological performance of the samples, three different loads (20 N, 40 N and 60 N) were applied to simulate body fluid (SBF) environment against stainless steel counterface. The scanning electron microscope was used to investigate the morphology of composite granules and worn surfaces of samples. Also, the hardness test was conducted for all samples. The results show that the hardness of high-density polyethylene increases significantly depending on the short carbon fiber content. 20 wt% SCFs reinforced composite exhibited the highest hardness, which is 34% improvement compared to the pure HDPE. However, the same trend was not observed for wear resistance of composites. Composites containing 10 wt% SCFs showed best wear performance in SBF fluid conditions.Öğe Mechanical and dynamic mechanical thermal properties of ensete fiber/woven glass fiber fabric hybrid composites(Elsevier Sci Ltd, 2021) Negawo, Tolera A.; Polat, Yusuf; Akgul, Yasin; Kilic, Ali; Jawaid, M.This study aimed to identify the effects of the stacking sequences on mechanical and dynamic mechanical properties of ensete/glass hybrid composites. The composites were fabricated by using 4 layers of carded ensete web and woven glass fabric by Vacuum-assisted resin transfer molding method. Mechanical and dynamic mechanical properties of hybrid composites were characterized. The test results showed that hybridization of ensete web with glass woven fabrics enhanced the mechanical properties of ensete composites. The morphology of fractured samples reveals that higher glass fibers pullout than ensete fibers in hybrid composites. The flexural properties also increased when glass fiber hybridized with ensete fiber and the optimum values obtained when it is used as the skin of the composite.The composites stacked as glass-ensete-glass (GEEG) showed higher storage modulus as compared to glass-ensete (GGEE) ensete composites whereas loss modulus of the composites reinforced with glass fiber exhibited the maximum value of 407 MPa and the height of the damping curve decreased in GEEG composite. Experimental studies showed that the ensete/glass fiber hybrid polyester composites can be used as load-bearing structures and components where high resistance to deformations and thermal stability is necessary.Öğe Mechanical, tribological, and biological properties of carbon fiber/hydroxyapatite reinforced hybrid composites(Wiley, 2020) Akgul, Yasin; Ahlatci, Hayrettin; Turan, Muhammet E.; Simsir, Hamza; Erden, Mehmet A.; Sun, Yavuz; Kilic, AliThe present study aims to investigate the effect of short carbon fiber (SCFs) and hydroxyapatite (HAp) content on mechanical, tribological, and biological properties of high-density polyethylene (HDPE) matrix composites. The proposed HDPE/SCFs-HAp hybrid composites with good mechanical-tribological behavior and biocompatibility might be used as novel implants in orthopedics. The composites were developed using twin-screw extrusion and compression molding methods. Hardness, tensile, and 3-point bending tests were performed to investigate the mechanical properties of hybrid composites. To evaluate wear performance of the samples, three different loads (10, 20, and 30 N) were applied in simulated body fluid. Biological activities of the hybrid composite samples were investigated. Results show that HDPE-10%SCFs-10%HAp sample provides optimum mechanical, tribological, and biological properties.Öğe Optimization of centrifugally spun thermoplastic polyurethane nanofibers for air filtration applications(Taylor & Francis Inc, 2018) Gundogdu, N. A. Serhat; Akgul, Yasin; Kilic, AliWhile our knowledge of fiber formation by using conventional nanofiber spinning techniques has increased to a considerable extent, there are still few studies on centrifugal spinning either in academia or in the industry. Centrifugal spinning is a comparatively new method of producing fibers having nano- or microscale diameters. In this study, three main parameters (nozzle orifice diameter, rotational speed, polymer concentration) of centrifugal spinning were optimized to produce air filter media from thermoplastic polyurethane nanofibers. The effect of concentration of polymer solution was found to be a major contributor in TPU fibers optimization estimating 77.5%. After the optimization studies, the average fiber diameter of nanofiber sample produced at optimum conditions (22G needle as an orifice, 4000rpm, and 10wt% concentration of polymer solution) was 205 84nm. Aerosol filtration performance of the produced webs was analyzed. Filtration efficiency of the optimized sample was found to be 99.4% for 0.3 mu m particle size at an expense of 98Pa pressure drop.Copyright (c) 2018 American Association for Aerosol ResearchÖğe Production of Ultrafine PVDF Nanofiber-/Nanonet-Based Air Filters via the Electroblowing Technique by Employing PEG as a Pore-Forming Agent(Amer Chemical Soc, 2023) Toptas, Ali; Calisir, Mehmet Durmus; Kilic, AliParticles with diameters smaller than 2.5 mu m (PM2.5) can penetrate the respiratory system and have negative impacts on human health. Filter media with a porous surface and nanofiber/nanonet structure demonstrate superior filtration performance compared to traditional nano- and microfiber-based filters. In this study, nanostructured filters were produced using the electroblowing method from solutions containing different ratios of poly(vinylidene fluoride) (PVDF) and polyethylene glycol (PEG) polymers for the first time. By increasing the water-soluble PEG ratio in PVDF/PEG blend nanofibers and employing a water bath treatment to the produced mat afterward, a more porous fibrous structure was obtained with a lower average fiber diameter. Notably, the removal of PEG from the PVDF/PEG (3-7) sample, which had the highest PEG content, exhibited clustered nanofiber-/nanonet-like structures with average diameters of 170 and 50 nm at the points where the fibers intersect. Although this process resulted in a slight decrease in the filtration efficiency (-1.3%), the significant reduction observed in pressure drop led to a 3.2% increase in the quality factor (QF). Additionally, by exploiting the polarizability of PVDF under an electric field, the filtration efficiency of the nanostructured PVDF filters enhanced with a ratio of 3.6% after corona discharge treatment leading to a 60% improvement in the QF. As a result, the PVDF/PEG (3-7) sample presented an impressive filtration efficiency of 99.57%, a pressure drop (Delta P) of 158 Pa, and a QF of 0.0345 Pa-1.Öğe Submicron aerosol filtration performance of centrifugally spun nanofibrous polyvinylpyrrolidone media(Sage Publications Inc, 2021) Melike, Gungor; Calisir, Mehmet D.; Akgul, Yasin; Selcuk, Sule; Ali, Demir; Kilic, AliIn this study, polyvinylpyrrolidone-based nanofibrous air filter media were produced via centrifugal spinning and subsequently stabilized by thermal cross-linking process. Samples were produced using solutions with three different polymer concentrations (5, 10 and 20 wt.%) and three different rotational speeds (4000, 6000 and 8000 r/min). After obtaining the optimum web structure with the lowest average fiber diameter and the most uniform distribution, the webs were later thermally cross-linked in order to stabilize polyvinylpyrrolidone against the degradative effects of water. In addition, the webs were subjected to dissolvability tests to see the efficacy of cross-linking treatment. Morphological, structural and chemical characterizations of the polyvinylpyrrolidone webs were performed by SEM, XRD and FTIR, respectively. Finally, filter efficiency and pressure drop were measured to assess filter performance. The results have shown that the lowest average fiber diameter is obtained at the highest rotational speeds. Subsequent thermal cross-linking treatment has been found to prevent fibers from dissolving in water. The produced water-resistant, environmentally friendly polyvinylpyrrolidone nanofibrous filter media has had a satisfactory filtration performance with a high filter efficiency of 99.995% and a high quality factor of 0.39 mm H2O-1.
