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Öğe Airlaid nonwoven panels for use as structural thermal insulation(Taylor & Francis Ltd, 2018) Çerkez, İdris; Koçer, Hasan Basri; Broughton, R. M.Thermal-bonded airlaid nonwoven webs consisting of fiber glass and polyester bicomponent fibers were manufactured, and then multilayer webs were formed into composite panels using compression molding technique. The consolidation process was optimized and the effect of bulk density on air permeabilites, mechanical properties, and thermal resistance was studied. Increasing binder amount and bulk density improved the flexural and tensile strength. Thermal resistance of the panels were found to be very dependent on the bulk density such that the resistance increased exponentially with an initial increase in density, then leveled off and decreased linearly with further increment in density. Depending on the composition and bulk density, the panels provided thermal resistance between 0.52 and 0.88Km(2)/W, tensile strength between 2 and 7MPa, and flexural strength between 600 and 3500kPa. The findings revealed that airlaid nonwoven panels can be designed to use as structural thermal insulation materials in constructions.Öğe Annealing studies on a thermotropic liquid crystalline polyester meltblown fabric(Sage Publications Inc, 2017) Koçer, Hasan Basri; Çerkez, İdris; Broughton, Royall M.Meltblown fabrics composed of a thermotropic liquid crystalline polyester were subjected to heat conditioning at various temperatures. Physical effect of the treatment was investigated by tensile testing of the fabrics and the individual fibers. The fabrics exhibited increased tensile strength by more than 100% after the heat conditioning due to inter-fiber bonding in the fabric structure and morphological reorganization of the thermotropic polymer. The calorimetric behavior of the polymer was further investigated to obtain information about the internal structure. Structural change during the annealing was also visually observed under a polarized light microscope.Öğe Antimicrobial functionalization of poly(ethylene terephthalate) fabrics with waterborne N-halamine epoxides(Wiley-Blackwell, 2016) Çerkez, İdris; Koçer, Hasan Basri; Worley, S. D.; Broughton, R. M.; Huang, T. S.A water dispersible terpolymer of [2-(methacryloyloxy)ethyl]trimethylammonium chloride, glycidyl methacrylate and hydantoinyl acrylamide was synthesized and coated on poly(ethylene terephthalate) fabrics through a pad-dry-cure procedure. The coatings were rendered biocidal upon exposure to dilute household bleach solution. The halogenated fabrics exhibited great antimicrobial functionality with about six logs inactivation of S. aureus and E. coli O157: H7 within only two min of contact time. Moreover, the coatings were found to be very stable against repeated washings and UVA light exposure. It was shown that [2-(methacryloyloxy)ethyl]-trimethylammonium monomer is very useful in preparing waterborne N-halamines which can impart rechargeable, effective, and stable antimicrobial coatings to poly(ethylene terephthalate) fabrics. (C) 2015 Wiley Periodicals, Inc.Öğe Antimicrobial open-cell polyurethane foams with quaternary ammonium salts(Wiley, 2018) Demirci, Fatma; Yıldırım, Kenan; Koçer, Hasan BasriAn hydroxyl-terminated quaternary ammonium salt polymer (QAP) was added to a foam formulation in various amounts between 1 and 5 wt %. The structures of the produced foams and their QAP content were characterized by Fourier transform infrared and EDXRF analyses. A linear polymer of QAP with a diisocyanate was also synthesized to support our investigations. The morphological changes such as the cell size and the cell structure of the produced foams were observed with scanning electron microscopy. Thermogravimetric analysis and dynamic mechanical analysis analyses were applied to examine the thermal and thermomechanical properties of the produced foams. Relatively low amount of QAP-added foams showed very similar structural and thermomechanical properties to the unmodified foams. In addition, while the unmodified foams did not show any antimicrobial activity, the QAP-added foams provided significant inactivation against Staphylococcus aureus, yeast and mold at concentrations of about 10(2) and 10(3) CFU within 5 h of contact time. The results showed that the addition of minute amount of QAP can significantly improve the biocidal performance of the produced foams without deteriorating their structure. (C) 2017 Wiley Periodicals, Inc.Öğe KESİT ŞEKLİNİN POLİ (L-LAKTİK ASİT) FİLAMENT İPLİK ÖZELLİKLERİNE ETKİSİ(Bursa Uludağ Üniversitesi, 2022) Çelen, Onur; Koçer, Hasan BasriBu çalışmada yenilenebilir kaynaklardan üretilen biyo bozunur ve biyo gübrelenebilir poli(L-laktik asit) (PLLA) polimerinden, eriyikten çekim eğirme prosesiyle filament iplikler üretilmiştir. Özel kesitli PLLA filament iplik üretimleri başarıyla gerçekleştirilmiş, bu kesitlerin sahip olduğu farklı yüzey morfolojilerinin ipliklerin yapısal ve fiziksel özelliklerine olan etkileri araştırılmıştır. Kesit şekilleri olarak en yaygın kullanılan dairesel kesitin dışında üçgen, artı, içi boş daire ve yassı biçimleri seçilmiştir. İpliklerin termal özellikleri ve kristalizasyon verileri DSC analizi ile, kimyasal özellikleri viskozite ve karboksil analizleriyle, fiziksel özellikleri ise mukavemet, uzama, düzgünsüzlük testleriyle karakterize edilmiştir. PLLA polimerinden eriyikten çekim eğirme prosesi ile endüstriyel özellikte özel kesitli filament iplikler başarı ile üretilmiştir.Öğe Mechanical and antibacterial properties of ZnO/chitosan bio-composite films(WALTER DE GRUYTER, 2021) Kalemtaş, Ayşe; Koçer, Hasan Basri; Aydın, Ahmet; Terzioğlu, Pınar; Aydın, GülsümIn the current study, ZnO/chitosan bio-composite films were produced via solution-casting method. Two different ZnO powders, micrometer (d(50) approximately equal to 1.5 mu m) and nanometer sized (d(50) approximately equal to 100 nm), were used to investigate the effect of ZnO particle size and concentration (0, 2, and 8% w/w of chitosan) on the mechanical and antibacterial properties of the ZnO/chitosan bio-composite films. The incorporation of the ZnO powders into the chitosan film resulted in an increase in the tensile strength (TS) and a decrease in the elongation at break (EB) values. Mechanical test results revealed that TS and EB properties were considerably affected (p < 0.05) by the concentration and particle size of the ZnO reinforcement. Disc diffusion method demonstrated good antibacterial activities of bio-composite films containing high amount of ZnO (8% w/w of chitosan) against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Bacillus subtilis. The growth-limiting effect of the films was more pronounced for S. aureus and K. pneumoniae. Due to enhanced TS and imparted antibacterial activity of the produced ZnO/chitosan bio-composite films, these materials are promising candidates for applications such as food packaging, wound dressing, and antibacterial coatings for various surfaces.Öğe N-(hydroxymethyl) acrylamide as a multifunctional finish to cotton and a tether for grafting methacrylamide for biocidal coatings(Wiley, 2013) Yildiz, Ozkan; Çerkez, İdris; Koçer, Hasan Basri; Worley, S. D.; Broughton, R. M.; Huang, T. S.N-(hydroxymethyl) acrylamide (NMA) was immobilized on cotton surfaces through etherification, and then methacrylamide (MA) was grafted onto the treated surface. The coatings were characterized by ATR-IR spectroscopy and were rendered biocidal upon exposure to dilute household bleach. The treated fabrics were challenged with Gram-negative and Gram-positive bacteria; both NMA and NMA/MA-treated fabrics inactivated about 8 logs of Escherichia coli O157:H7 and Staphylococcus aureus within only 5 min of contact time. The coatings were also quite stable toward ultraviolet (UVA) light exposure and repeated laundering. Moreover, a substantial improvement in wrinkle recovery angle was obtained for the NMA/MA-treated fabrics. The new acyclic acrylamide N-halamine coating should be less expensive to produce and use than previous cyclic N-halamine coatings developed in these laboratories. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013Öğe Preparation of antibacterial polyvinylidene fluoride (PVDF) ultrafiltration membranes with direct addition of N-halamine polymers(Taylor & Francis Inc, 2019) Demirci, Fatma; Koçer, Hasan BasriIn this study, novel antibacterial ultrafiltration polyvinylidene fluoride (PVDF) flat sheet membranes were produced with addition of synthesized N-halamine polymers. The ternary phase diagrams of PVDF and the synthesized polymers with N-methyl-2-pyrrolidone and water systems were prepared. The water flux and BSA rejection performances of the produced membranes were assessed both with and without PVP addition, and compared with a commercial membrane. The produced membranes were characterized with FTIR, XPS, DSC, and SEM analysis. Addition of N-halamine polymers to the membrane structure significantly improved the biocidal performance of the produced membranes against Staphylococcus aureus and Escherichia coli (10(5) CFU).Öğe Preparation of breathable polyurethane membranes with quaternary ammonium salt diols providing durable antibacterial property(Wiley, 2019) Aydın, Ahmet; Demirci, Fatma; Orhan, Mehmet; Koçer, Hasan BasriAim of this study was to produce hydrophilic breathable polyurethane membranes providing antibacterial property permanently by incorporation of a quaternary ammonium salt diol (QAS). The study was carried out by synthesis of nine different polyurethanes by solution polymerization through variations of their QAS and isocyanate contents. Fully amorphous membranes at a thickness of 30m were produced from the synthesized polymers and their thermal and morphological characteristics were determined. The effect of morphological structures on the membrane water vapor transmission rates (WVTR) and antibacterial properties were correlated. The WVTR increased with the increased temperature in all membranes over 10-40 degrees C, all produced membranes showed water resistance up to a pressure of 2100 cmH2O and WVTR values above 60g/m(2) h at 30 degrees C. The WVTR increased by increasing amount of QAS including cationic groups and decreased by increasing isocyanate amount reducing the molecular chain flexibility. In addition, while the unmodified membranes did not show any antibacterial activity, the QAS-added membranes provided significant inactivation against Staphylococcus aureus and Escherichia coli of about 104CFU within 5h of contact time. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47133.Öğe Spinnability and characterization of poly(D-lactic acid)-blended poly(L-lactic acid) filament yarns(Wiley, 2021) Çelen, Onur; Koçer, Hasan BasriConventional textiles are produced mainly by petroleum-based polymeric materials, which are not biodegradable, cause serious pollution, and waste problems. Especially, poly(ethylene terephthalate) is the most used thermoplastic polyester in various textile applications. At this point, poly(lactic acid) (PLA), a biodegradable polyester, stands out forward with its unique properties. PLA is derived from renewable sources such as corn, sugar cane, and so on. In this study, poly(D-lactic acid) (PDLA) was blended to poly(L-lactic acid) (PLLA) to reduce its highly crystalline morphology and rigidity. Introduction of PDLA would be expected to speed up its degradation by decreasing the amount of crystalline regions. PDLA was compounded into PLLA in amounts of 3, 6, and 9 wt%. First, PDLA-blended PLLA compounds were produced, and then successfully spun/drawn into filament yarns by using a pilot-scale melt spinning equipment. The compounds and the filament yarns were characterized by SEM, DSC, viscosity, carboxyl number, tenacity, elongation at break, unevenness, and shrinkage. Results showed that the amount of crystalline regions was decreased with increasing PDLA amount in both compounds and filament yarns. On the other hand, PDLA blending enhanced the rigidity of filament yarns by increasing their elongation at break.Öğe Supercritical carbon dioxide application using hydantoin acrylamide for biocidal functionalization of polyester(Elsevier, 2020) Orhan, Mehmet; Demirci, Fatma; Koçer, Hasan Basri; Nierstrasz, VincentBiocidal functionalization in polyester fibers is a really tough challenge because of the lack of tethering groups. This study indicated supercritical carbon dioxide application using N-halamine would be an alternative solution for obtaining antibacterial function on the polyester surface. Firstly, N-(2-methyl 1-(4 methyl-2,5-dioxo-imidazolidin-4 yl)propan-2-yl)acrylamide was synthesized and applied to the polyester in supercritical carbon dioxide medium, at 120 degrees C, 30 MPa for different processing times. The addition of N-halamine on the surface significantly brought antibacterial activity against E. coli. The chlorine loadings showed that 6-h exposure time was critical to obtain sufficient antibacterial activity. This treatment caused a reasonable and tolerable loss in color and mechanical properties. But, the durability to abrasion, stability, and rechargeability of oxidative chlorine, and the durability of N-halamine on the surface were remarkably good. Conclusively, it can be available to work on polyester surfaces with resource-efficient and eco-friendly supercritical carbon dioxide technique for getting more functionalization and modification. (C) 2020 Elsevier B.V. All rights reserved.Öğe Treatment of melamine formaldehyde fibers for decontaminating biological and chemical warfare agents(Wiley, 2015) Koçer, Hasan Basri; Özkan, Fatma; Broughton, Roy M.; Worley, Shelby D.The demand for protection against biological and chemical warfare agents has increased the need for unique protective materials. N-halamines are superior candidates for this task by having rapid inactivation rates against a broad range of microorganisms and the ability to oxidize some pesticides and warfare agents to reduce their toxicity to humans. Thus, the design of N-halamine materials having fibrous structure, high halogen loading capacity with enhanced stability, and being relatively inexpensive is very important. This study investigated the effect of acid treatment on the chlorine loading and stability of a commercial flame retardant melamine formaldehyde (MF) fiber to introduce biocidal and detoxifying properties. The fibers formed into a web were treated with diluted sulfuric acid (H2SO4) under various conditions. The fiber webs were chlorinated with household bleach, and the stability of bound chlorine was investigated. The treated fabrics have been tested against a Gram-negative bacterium and a warfare stimulant. (c) 2015 Wiley Periodicals, Inc.
