Yazar "Tayfun, Umit" seçeneğine göre listele
Listeleniyor 1 - 12 / 12
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Beneficial use of mussel shell as a bioadditive for TPU green composites by the valorization of an aqueous waste(Springernature, 2024) Sismanoglu, Sedef; Kanbur, Yasin; Popescu, Carmen-Mihaela; Kindzera, Diana; Tayfun, UmitScientific studies have focused on environmentally friendly solutions as effective as the reuse of crop products owing to plastic-waste problems in recent years. This issue is the main driving force for upcoming academic research attempts in waste valorization-related studies. Herein, we integrated an aqua-waste, mussel shell (MS), as a bioadditive form into green thermoplastic polyurethane (TPU) green composites. Tuning of the MS surface was performed to achieve strong adhesion between composite phases. The surface functionalities of MS powders were evaluated via infrared spectroscopy and scanning electron microscopy (SEM) images. Composite samples were prepared by melt-compounding followed by injection molding techniques. It was confirmed by morphological analysis that relatively better adhesion between the phases was achieved for composites involving surface-modified MS compared to unmodified MS. Tensile strength and Young's modulus of surface-modified MS-filled composites were found to be higher than those of unmodified MS, whereas the elongation at break shifted to lower values with MS inclusions. The shore hardness of TPU was remarkably improved after being incorporated with silane-treated MS (AS-MS). Stearic acid-treated MS (ST-MS) additions resulted in an enhancement in the thermal stability of the composites. Thermo-mechanical analysis showed that the storage moduli of composites were higher than those of unfilled TPU. ST-MS additions led to an increase in the characteristic glass transition temperature of TPU. Melt flow index (MFI) of neat TPU was highly improved after MS loading regardless of modification type. According to the wear test, surface modification of MS displayed a positive effect on the wear resistance of TPU. As the water absorption data of the composites were evaluated, the TPU/AS-MS composite yielded the lowest water absorption. The silane layer on MS inclusion promoted water repellency of composites due to the hydrophobicity of silane. The results of the biodegradation investigation demonstrated that adding unmodified and/or modified MS to the TPU matrix increased the biodegradation rate. The test results at the end of a 7-week period of biodegradation with a soft-rot fungus implied that the composite materials were more biodegradable than pure TPU. Silane modification of MS exhibited better performance in terms of the characterized properties of TPU-based composites.Öğe Development of multifunctional polyurethane elastomer composites containing fullerene: Mechanical, damping, thermal, and flammability behaviors(Sage Publications Ltd, 2019) Kanbur, Yasin; Tayfun, UmitThermoplastic polyurethane (TPU) composites filled with fullerene in the range from 0.5 wt% to 2 wt% were fabricated using melt-compounding. Fullerene addition levels up to nearly twofold increase in tensile strength, percent elongation, and modulus of TPU. The mechanical properties are improved as modified C-60 content decreases. Fullerene loadings also enhance thermal stability of TPU. Glass transition temperature decreases by the inclusion of C-60 into TPU matrix. Composites exhibited the improvement for storage modulus and vibration-damping behavior. The UL-94 rating and limiting oxygen index value of TPU are also extended to higher values after C-60 loadings. Adjuvant effect is observed on fire performance in which pristine C-60 inclusions and higher concentrations of C-60 exhibit better fire performance. Additions of C-60 give identical melt flow index values with that of TPU. Modified C-60 particles disperse more homogeneously than pristine ones into TPU matrix because of the improvement in interfacial interactions between fullerene and polyurethane elastomer.Öğe Effect of alkali and silane surface treatments on the mechanical and physical behaviors of date palm seed-filled thermoplastic polyurethane eco-composites(Sage Publications Ltd, 2022) Sismanoglu, Sedef; Tayfun, Umit; Kanbur, YasinIn this study, eco-grade thermoplastic polyurethane (TPU), which includes 46% renewable content, was reinforced with date palm seed (DPS). Alkali and silane surface treatments were applied to DPS to increase the compatibility between DPS and TPU matrix. The oil of DPS was removed before treatments and surface functionalities of modified and pristine DPS samples were examined by Fourier transform infrared spectroscopy. Composites were fabricated using melt blending method and injection molding processes. Test samples of composites were characterized using tensile test, hardness test, water absorption study, dynamic mechanical analysis (DMA), melt flow index (MFI) test, thermogravimetric analysis, and scanning electron microscopy (SEM). According to test results, silane treatment led to remarkable improvement for mechanical performance of composites attributed to improvement of compatibility and interface adhesion between DPS and TPU. DMA results implied that higher storage modulus and glass transition temperature were achieved for treated DPS-containing composites compared to pristine DPS filled ones. Thermal stability of flexible segment of TPU increased with the addition of DPS regardless of surface treatment. Additionally, DPS loadings caused significant increase in MFI value of unfilled TPU. Silane-treated DPS-containing composite yielded the lowest water uptake value among samples due to the hydrophobicity of silane layer. Enrichment of interface adhesion of DPS to TPU matrix was confirmed by SEM micrographs of composites. Silane-treated DPS-containing composite displayed higher results among produced composites since the increase in interfacial interactions with TPU was achieved by silane treatment for DPS surface.Öğe Effect of silane-modification of diatomite on its composites with thermoplastic polyurethane(Elsevier Science Sa, 2020) Kucuk, Fatma; Sismanoglu, Sedef; Kanbur, Yasin; Tayfun, UmitDiatomite (KG) surface was modified by four different silane coupling agents having amino, epoxy, triamine and octyl functional groups for enhancement of interfacial adhesion between thermoplastic polyurethane (TPU) and diatomite. EDX and FTIR spectroscopy techniques were used to evaluate the surface functionalities of modified and neat KG samples. TPU/KG composites were fabricated using melt-compounding process. Mechanical, thermo-mechanical, thermal, melt-flow and morphological properties of composites were reported. Mechanical tests revealed that tensile strength and hardness of TPU extended to higher levels while its flexibility was retained after KG additions. Epoxy-silane modified KG exhibited the highest results in the case of mechanical properties. Glass transition temperature of TPU shifted to higher values by the additions of modified KG. Thermal stability of TPU raised by KG inclusions regardless of modification type. Modified KG containing composites yield lower MFI values with respect to neat KG. Enhancement of interfacial adhesion between TPU and KG phases was confirmed by SEM micrographs of composites in which silane-modified KG surfaces were covered by TPU matrix. Silane modifiers involving amine and epoxy groups led to significant improvement in properties of KG-filled TPU composites. Epoxy-based silane displayed the highest performances thanks to strong interfacial interactions between epoxy functional group and isocyanate segment of TPU.Öğe Effective use of olive pulp as biomass additive for eco-grade TPU-based composites using functional surface modifiers(Springer Heidelberg, 2023) Sismanoglu, Sedef; Tayfun, Umit; Popescu, Carmen-Mihaela; Kanbur, YasinOlive pulp, which is formed 80% in the olive oil extraction process, attracts the attention of researchers with the zero waste project in Turkey. Our study aims to prove that olive pulp is not only a waste and can be used as a resource when used correctly as a filler in composite materials to provide not only durable but also shorter biodegradation times for polymer-based composite materials. The surface modification process with 3 different silanes containing epoxy, vinyl, and amino groups was applied to the surface of olive pulp (OP) to solve the problem of surface incompatibility with eco-grade thermoplastic polyurethane (TPU) matrix. The oil portion of OP was removed before silane treatments. Surface functions and thermal properties of both modified and unmodified OP powder samples were evaluated by FTIR, SEM, and TGA techniques, respectively. TPU/OP composites were fabricated using melt-compounding process, and mechanical, thermomechanical, thermal, melt flow, wear, biodegradation, and morphological properties of composites were reported. According to test results, TPU/VS-OP (vinyl silanized olive pulp) composite showed the highest hardness and wear resistance values among all composites. Additionally, silane modifications led to remarkable improvements for mechanical, thermal, thermomechanical, and melt flow properties of composites thanks to the enhancement of compatibility and interface adhesion between OP and TPU phases. It seems that VS-OP containing composite sample displayed the highest results in most of the examined results. It has been shown that the addition of unmodified and modified OP filler to TPU caused to level of the biodegradation of pure TPU, and as a result, environmentally friendly composites have been produced.Öğe Investigating mechanical, thermal, and flammability properties of thermoplastic polyurethane/carbon nanotube composites(Sage Publications Ltd, 2018) Kanbur, Yasin; Tayfun, UmitThermoplastic polyurethane (TPU) composites containing carbon nanotube (CNT) with the loading ratios from 0.5wt% to 2 wt% were prepared using melt-compounding process. Surfaces of the CNT particles were treated with sulfuric acid/nitric acid to purify CNT and to achieve compatible surface characteristics between TPU matrix and CNT. Mechanical, thermal, flame retardant, melt flow, and morphological properties of TPU/CNT composites were investigated. Addition of CNT to TPU matrix causes in a prominent increase in tensile strength, percentage of elongation at break, and tensile modulus values of TPU. The mechanical properties are improved for lower modified CNT loadings. CNT inclusions also improve the thermal stability of pristine TPU. Addition of CNT into TPU matrix causes increase in melting and decomposition temperatures of TPU and decrease in glass transition temperature. The flammability parameters of TPU also shift to higher values after CNT loadings to matrix. Modified CNT additions at higher concentrations exhibit better fire performance. Additions of modified CNT and pristine CNT show different trends in the case of melt flow rate values. Modified CNTs disperse more homogeneously relative to pristine ones into TPU matrix which is due to improvement in interfacial interactions between CNT and TPU.Öğe Mechanical, electrical, and melt flow properties of polyurethane elastomer/surface-modified carbon nanotube composites(Sage Publications Ltd, 2017) Tayfun, Umit; Kanbur, Yasin; Abaci, Ufuk; Guney, Hasan Yuksel; Bayramli, ErdalCarbon nanotube-reinforced polyurethane elastomer composites were prepared by melt-mixing. Nitric acid oxidation and silanization were applied to carbon nanotube surfaces to achieve better interfacial interactions with polyurethane elastomer. Tensile and hardness tests, differential scanning calorimetry, melt flow index test, dielectric measurements, and morphological studies of composites were reported. The best results were obtained for surface-modified carbon nanotubes containing composites with lower loading levels. Addition of carbon nanotubes leads to almost two-fold increase in strain and modulus compared to pristine polyurethane elastomer. Tensile strength of composites was also improved by inclusion of carbon nanotubes. However, strength values drop down with increasing carbon nanotube content. Shore hardness increased with the inclusion of modified carbon nanotube to polyurethane elastomer while pristine carbon nanotube caused remarkable decrease in hardness of polyurethane elastomer. Relatively higher melting points and slightly lower glass transition temperatures were observed for carbon nanotube-loaded composites compared to polyurethane elastomer because of plasticizing effect of carbon nanotube. Incorparation of carbon nanotube to polyurethane elastomer matrix caused reduction in melt flow index values due to formation of agglomarates, and n the contrary, surface modifications of carbon nanotube exhibited increase in melt flow index thanks to enhanced interfacial interactions between carbon nanotube and polyurethane elastomer. Significant increase in dielectric constant of composites was observed. Better dispersion of surface modified carbon nanotubes into polyurethane elastomer was also concluded from SEM micrographs of composites.Öğe Mechanical, flow and electrical properties of thermoplastic polyurethane/fullerene composites: Effect of surface modification of fullerene(Elsevier Sci Ltd, 2015) Tayfun, Umit; Kanbur, Yasin; Abaci, Ufuk; Guney, Hasan Yuksel; Bayramli, ErdalThermoplastic polyurethane (TPU) composites with fullerene loadings varying from 0.5 to 2 weight% were prepared by melt-mixing method. Nitric acid oxidation and silanization were applied to fullerene surface to improve interfacial interactions with TPU matrix. The influence of surface modifications of fullerene on mechanical, melt flow and electrical properties of TPU based composites were investigated. Incorporation of fullerene leads to nearly twofold increase in tensile strength and Young's modulus of the composites in addition to enhancing the flexibility. The best results are obtained in nitric acid and silane modified fullerene containing composites at the lowest concentration (0.5%). Higher MFI values were observed for composites loaded with surface treated fullerenes compared to pristine fullerene because of their better dispersion in TPU. Electrical properties of TPU also improved by the addition of surface modified fullerene particles. Surface oxidation and silanization gave rise to dispersion homogeneity which may be the reason of both tensile strength and strain improvements at the same time. (C) 2015 Elsevier Ltd. All rights reserved.Öğe Mechanical, thermo-mechanical and water uptake performance of wood flour filled polyurethane elastomer eco-composites: influence of surface treatment of wood flour(Walter De Gruyter Gmbh, 2019) Kilinc, Kerim; Kanbur, Yasin; Tayfun, UmitAlkaline and silane treatments were applied to wood flour (WF) to enrich its adhesion to bio-based thermoplastic polyurethane (TPU) matrix. TPU/WF eco-composites were prepared at a constant ratio of 30% by the melt blending process. The mechanical, thermo-mechanical, melt-flow, water uptake and morphological properties of the materials were investigated. Silane-treated WF filled composite exhibited better mechanical performance with respect to untreated WF due to enhancement of adhesion between WF and TPU matrix after surface treatments. This sample also gave the lowest water absorption value among composites. The results confirmed that silane treatment of WF led to significant improvement on the mechanical and physical properties of TPU-based composites in addition to an improved water resistance for outdoor applications.Öğe Optimization of mechanical, thermo-mechanical, melt-flow and thermal performance of TPU green composites by diatomaceous earth content(Elsevier, 2021) Kucuk, Fatma; Sismanoglu, Sedef; Kanbur, Yasin; Tayfun, UmitIn the present paper the effect of the diatomite, also known as diatomaceous earth and kiesel guhr (KG), content on mechanical, thermo-mechanical, melt-flow and thermal performance of thermoplastic polyurethane-based composites was investigated. Composites were fabricated by melt blending method with 10, 20, 30 and 40% filling ratios of KG. and injection molded test samples were characterized using tensile, hardness, dynamic mechanical analysis (DMA), melt flow index (MFI), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) analysis. According to test results, KG inclusions effect mechanical, thermal and morphological properties of composites positively up to 30% KG content. Further addition of KG caused remarkable reductions in related properties. Tensile strength of unfilled TPU exhibited increasing trend and elongation showed no obvious difference after KG loadings. TPU/KG composites yield relatively higher MFI values with respect to unfilled TPU. Glass transition temperature of TPU shifted to 6 points higher value by the help of KG incorporation. TGA findings revealed that KG additions caused improvement for thermal stability of TPU. Homogeneous dispersion of KG particles for their lower content, whereas agglomorate formations for higher loading level of KG were confirmed by SEM micrographs. TPU composite containing 10% KG showed the highest results among samples.Öğe Reuse of black cumin biomass into beneficial additive for thermoplastic polyurethane-based green composites with silane modifiers(Springer Heidelberg, 2023) Sismanoglu, Sedef; Tayfun, Umit; Gradinariu, Petronela; Popescu, Carmen-Mihaela; Kanbur, YasinRich in protein, carbohydrates, and lignocellulosic, black cumin is a plant that is used in the treatment of many diseases and has antioxidant and anti-tumor properties. Apart from its use in medicine, black cumin is used as a filler in the production of new and eco-friendly eco-composites to reduce the environmental pollution caused by petroleum-based classical polymer composite materials. In this study, bio-based thermoplastic polyurethane (TPU) polymer was used as a matrix and black cumin unmodified and modified with 3 different functionalized group silanes, was added as a filler and mixed in a twin-screw extruder, and biocomposite materials in the form of dog-bones were produced by injection molding. Black cumin powders were analyzed by Fourier-transform infrared-attenuated total reflection (FTIR/ATR), field effect scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA), while the mechanical, tribological, morphological, thermal, thermo-mechanical, melt flow index, and biological properties of the produced biocomposites were characterized. According to the results obtained, it was seen that surface treatment of the black cumin with silane both improved the biodegradability and other properties of eco-composites. Among thermoplastic polyurethane-based eco-composites, surface modification of black cumin with 3-aminopropyltriethoxysilane had the lowest water absorption capacity of 8% and also the highest abrasion resistance and an improvement of 88.5%. It was observed that the eco-composite containing octyldecyl-modified black cumin had the lowest MFI value of 26, the best biodegradability among the surface-modified eco-composites, the tensile strength of 14.5 MPa, and the highest value compared to other eco-composites. Epoxy-silane modifier yields optimum results in terms of thermal and thermo-mechanical analysis.Öğe THE USE OF MUSSEL SHELL AS A BIO-ADDITIVE FOR POLY(LACTIC ACID) BASED GREEN COMPOSITES(Lviv Polytech Natl Univ, 2021) Lap, Metehan Ogulcan; Kanbur, Yasin; Tayfun, UmitMussel shell is one of the most hazardous aquaculture wastes and its powder was used as an additive for bio-degradable poly (lactic acid) in this current study. Bio-composites were fabricated via conventional melt mixing technique followed by an injection moulding process. The effects of mussel shell powder inclusion on mechanical, melt-flow, water uptake and morphological performance of poly (lactic acid)-based green composites were reported.
