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Öğe Adsorption of hexavalent chromium from aqueous solutions by bio-chars obtained during biomass pyrolysis(ELSEVIER SCIENCE INC, 2013) Deveci, Huseyin; Kar, YakupIn this study, bio-chars were evaluated as a potential adsorbent for the removal of Cr (VI) ions from aqueous solutions. The effects of some important parameters including initial pH (1.5-7), adsorbent dose (0.2-5 g/L), contact time (5-900 min) and initial Cr (VI) ion concentration (5-75 mg/L) were tested on the removal of Cr (VI) ions from aqueous solution in batch experiments. Maximum adsorption capacities of the tested bio-chars under the certain experimental conditions determined as optimal were 3.53 mg/g for NCBC, 3.97 mg/g for NZCBC and 6.08 mg/g for ACBC, respectively. Results of the kinetic and isotherm modeling studies revealed that the adsorption data fitted well with a pseudo-second order and Langmuir model. In among the tested bio-chars, the bio-char (ACBC) was largely equivalent to activated carbon: AC (9.97 mg/g) in terms of adsorption capacity. All results indicated that the bio-chars had higher adsorption capacity than some chars and activated carbons reported previously, and also that these bio-chars could be used successfully as low-cost adsorbents for the removal of chromium ions from aqueous solutions under the tested experimental conditions. (C) 2012 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.Öğe Coating, mechanical and thermal properties of epoxy toluene oligomer modified epoxy resin/sepiolite composites(ELSEVIER SCIENCE SA, 2012) Ahmetli, Gulnare; Deveci, Huseyin; Soydal, Ulku; Seker, Asli; Kurbanli, RefikaIn this research, epoxy toluene oligomer (ETO) was synthesised from toluene and epichlorhydrin, which was used as co-matrix in 50 wt.% with commercial epoxy resin (ER). Its chemical structure was characterised with FTIR spectroscopy and chemical analyses. ETO was found as an effective flame retardant for ER. Modification of ER with ETO in 50 wt.% increased percentage elongation at break of neat ER about 67 times. The rigid filler used in epoxy polymer matrix was the modified and unmodified sepiolite. The appropriate sepiolite amount in all cases was determined to be 5 wt.%. Scanning electron microscopy (SEM) was used for characterisation of surface and cross sections of the composites to verify the results. Modification of sepiolite increases the T-5, T-10, and T-50 of neat ETO-ER by 10, 7, and 5 degrees C, respectively. Surface hardness and tensile strength of all composites were higher than those of neat ETO-ER polymer matrix. ETO-ER/modified sepiolite coating showed the best adhesion results and exhibited perfect resistance to 3% NaCl and 10% NaOH solutions. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.Öğe Corrosion and thermal characterization of styrene based copolymers(ELSEVIER SCIENCE SA, 2011) Ahmetli, Gulnare; Deveci, Huseyin; Altun, Ahmet; Kurbanli, RefikaFilms from copolymers with resistance to wear, corrosion and thermal degradation as well as other important functions have been applied in many fields. It is known that the introduction of anionic hydrophilic groups in the polymer enhances its adhesion to substrates and protective function. In the present work, copolymers of styrene with acrylic, methacrylic and itaconic acids were prepared by polymerization in toluene with benzoyl peroxide initiation (BPO) and have been tested as anticorrosive films. The copolymers were analyzed by FTIR and TGA methods. Polarizing microscope images were employed to characterize the anticorrosive properties of the formed films. All copolymers produced in this work show strong adhesion to the substrate. (C) 2010 Elsevier B.V. All rights reserved.Öğe Epoxy resin/polymer blends: Improvement of thermal and mechanical properties(WILEY-BLACKWELL, 2012) Ahmetli, Gulnare; Deveci, Huseyin; Soydal, Ulku; Gurler, Sevgi Pistil; Altun, AhmetFatty acid waste was recycled as raw material and utilized to synthesize epoxy (HP) or unsaturated ester group (OEE) containing polymers. The radicalic polymerization between the styrene and itaconic acid was carried out, too. Glycidyl ester of styrene-itaconic acid copolymer was obtained by esterification reaction with epichlorohydrin. The polymers were characterized by means of Fourier transform infrared spectroscopy and chemical analysis. The polymers were incorporated into diglycidyl ether of bisphenol A type commercial epoxy resin to prepare composites. The effects of polymer structure and amount on the physico-mechanical and thermal properties of epoxy were investigated. Surface hardness, tensile strength, percentage elongation and stress at maximum load of the composites were obtained higher than pure epoxy resin. The composites reinforced with bio-based polymers showed about 74.55243% increase in elastic modulus over the pure epoxy matrix. Obtained Young's modulus values were higher for composites with styrene-based polymers. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012Öğe Importance of P-series fuels for flexible-fuel vehicles (FFVs) and alternative fuels(TAYLOR & FRANCIS INC, 2006) Kar, Yakup; Deveci, HuseyinAs engine fuels, the most popular alternative fuels are bioetanol, biodiesel, and hydrogen. Recently, in addition to these, there are intensive researches on methyl-, and ethylalcohols, natural gas, liquefied petroleum gas, P-series, electricity, and solar fuels. Alternative fuels for diesel engines are becoming increasingly important due to diminishing petroleum reserves and the environmental consequences of exhaust gases from petroleum-fueled engines. One of the advantages of P-series is that they are very easy to use. There is no need for any special fuel management because gasoline and P-series can be freely intermixed in any proportion with fuel that is already in the vehicle's fuel tank. So, even if P-series is not available at a particular location, simply fill up with gasoline. These fuels are inexpensive fuels generated by municipal and agricultural wastes. The National Renewal Energy Laboratory (NREL) showed that P-series would be 96% derived from domestic resources and reduce petroleum use by 80% as compared to gasoline. Use of P-series fuels also greatly reduces toxic emissions. P-fuels are economically competitive with gasoline. As of May 2003, the projected retail price for P-series, including all taxes, is $1.49 per gallon, about the same as mid-grade gasoline in a $/mile calculation. There are 3 million cars on the road today that could run on P-series fuels.Öğe Mechanical and thermal properties of a novel composite prepared with epoxy resin and lateritic ore(WILEY-BLACKWELL, 2013) Deveci, HuseyinComposites made from epoxy resins (ERs) are one of the important polymer groups used in different industries due to their good mechanical and thermal properties. Many attempts have been done to improve both the mechanical and the thermal properties of ER composites and to lower the cost of ER composites with addition of inexpensive fillers such as calcium carbonate, kaolin clays, silica, talc, etc. In this study novel lateritic ore (LO) filler was used in diglycidyl ether of bisphenol A-type ER. Different addition percentages (5-20%) of both natural LO (nLO) and modified LO (mLO) into ER were tested to determine the influence on mechanical and thermal properties of newly produced composites. Surface hardness, Young's modulus, tensile strength, elongation at break, water sorption, adhesion, and thermal stability of composites were determined and were compared with pure ER. Results showed that the addition of nLO/mLO has positive effect on mechanical and thermal properties. Morphological characterization by scanning electron microscopy and structural characterization by X-ray diffraction revealed that addition nLO/mLO distributed homogenously throughout the composites. POLYM. COMPOS. 34:1375-1381, 2013. (c) 2013 Society of Plastics EngineersÖğe Physico-mechanical, thermal, and coating properties of composite materials prepared with epoxy resin/steel slag(WILEY, 2017) Guzel, Gulcihan; Deveci, HuseyinThe interest in using different solid waste as reinforcement in polymer composite preparation has increased considerably in recent years. Slag is one of the inorganic waste materials obtained from ore processing. In this work, epoxy composites filled with different percentages of slag were prepared. Physico-mechanical, thermal, and coating properties of these composites were determined depending on the amount of filler, type of hardener, and polyethylene glycol (PEG) addition. X-ray diffraction (XRD) studies were carried out to examine the compatibility of the filler and epoxy resin and XRD results showed good compatibility between two materials. The results of mechanical testing illustrated that hardness of the epoxy composites containing anhydride was partially higher than with Epamine PC17 in contrast to elongation at break. The tensile strength and Young modulus decreased with increasing filler amount. When compared to neat epoxy resin, corrosion, and adhesion properties of the composites with filler addition did not change significantly. The highest water sorption values were obtained for the epoxy composites with PEG addition. The composites hardened by anhydride had better thermal stability than the composites including Epamine PC17. POLYM. COMPOS., 38:1974-1981, 2017. (c) 2015 Society of Plastics EngineersÖğe Preparation and characterization of pH-sensitive semi-interpenetrating network hybrid hydrogels with sodium humate and kaolin(ELSEVIER SCIENCE BV, 2018) Yilmaz, Elif; Kaya, Gulcihan Guzel; Deveci, HuseyinPoly(acrylamide-co-methacrylic acid) semi-interpenetrating network (semi-IPN) hybrid hydrogels including sodium humate and kaolin were successfully synthesized as confirmed with X-ray diffraction (XRD) and Fourier transforms infrared spectroscopy (FTIR) analyses. Scanning electron microscopy (SEM) analysis indicated uniform dispersed morphology of the hydrogels. It was specified with thermogravimetric-derivative thermogravimetric analysis (TGA-DTG) that the addition of kaolin provided to increase thermal decomposition temperatures of the hydrogels. The semi-IPN hybrid hydrogel exhibited highest equilibrium swelling percent (ESP) of 28,700% and 3440% in distilled water and 0.1 M NaCl, respectively. The hydrogels had better swelling behavior in basic medium compared to acidic medium. While the ESP value of semi-IPN hybrid hydrogel was about 1590% at pH 2, it was determined as 7046% at pH 9. Each hydrogel showed non-Fickian type diffusion and excellent biocompatibility (> 0.94). The results suggested that the obtained pH-sensitive semi-IPN hydrogels with unique properties can be used as biomaterial, adsorbent, membrane, sensor component and so on.Öğe Properties of Polymer Composites Based on Bisphenol A Epoxy Resins With Original/Modified Steel Slag(WILEY, 2018) Guzel, Gulcihan; Deveci, HuseyinRecently, many inorganic solid wastes have accumulated as a byproduct in several industries and their storage is one of the major problems. Among these wastes, steel slag has attracted attention to utilize with different purposes. In this study, original steel slag (OS) and modified steel slag (MS) were evaluated as a filler to prepare low-cost epoxy composites. The effect of components on the properties of steel slag/epoxy composites (SECs) was investigated with various analyses and tests. Physicomechanical and thermal properties of the SECs were compared with each other and neat epoxy resin (ER). Good dispersion of OS and MS in the ER matrix was determined with X-ray diffraction (XRD) pattern and scanning electron microscopy (SEM). Tensile strength, Young modulus, and hardness values of the SECs were enhanced after modification of OS. Any change on adhesion and corrosion resistance of the SECs was not observed; however water sorption percent was increased with the addition of components. As per thermogravimetric analyses (TGA) and vicat softening temperature (VST) analyses, SECs cured with anhydride showed higher decomposition temperature than the other hardener. Also, PEG addition slightly decreased thermal stability of the SECs. (C) 2016 Society of Plastics EngineersÖğe Recycling studies of marble processing waste: Composites based on commercial epoxy resin(WILEY-BLACKWELL, 2012) Ahmetli, Gulnare; Dag, Mustafa; Deveci, Huseyin; Kurbanli, RefikaMarble waste was obtained from marble processing plant wastewater with precipitation using different coagulants, such as sepiolite, zeolite, and pumice in dosages of 0.58 g/500 mL and mixed in 20 wt % with commercial epoxy resin. The effects of marble, coagulant type and dosage on the physicomechanical and thermal properties were investigated. The incorporation of marble processing waste particles increases the 10% decomposition temperature of pure epoxy by 550 degrees C. Surface hardness, tensile strength, percentage elongation, and stress at maximum load of the composites were higher than those of pure resin, too. The composites reinforced with marble processing waste-pumice showed about 10% increase in elastic modulus, whereas the composite reinforced with marble processing waste-sepiolite or zeolite showed about 76.67143.33% increase in elastic modulus over the pure epoxy matrix. Scanning electron microscopy (SEM) was used for characterization of surface and cross sections of the composites to verify the results. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012Öğe Sustainable bean pod/calcined kaolin reinforced epoxy hybrid composites with enhanced mechanical, water sorption and corrosion resistance properties(ELSEVIER SCI LTD, 2018) Kaya, Gulcihan Guzel; Yilmaz, Elif; Deveci, HuseyinThe industrial and academic world is becoming more interested in advanced composite materials owing to the increasing global awareness on environmental and social issues. From this point of view, novel epoxy hybrid composites were prepared by utilizing bean pod as an agricultural waste and calcined kaolin with the addition of varying ratios (0.5-5.0 wt%) to fixed weight of 3 wt% bean pod. The resulting hybrid composites were characterized by different analyses and tests to evaluate physico-mechanical and thermal properties. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses showed uniform dispersion of hybrid filler in the neat epoxy resin which revealed better compatibility between hybrid filler and epoxy resin. Tensile strength of hybrid composite including 2 wt% calcined kaolin (39.8 MPa) was higher than those of the other hybrid composites. The water sorption percentage of the hybrid composites was effectively decreased until 0.87% with increasing amount of calcined kaolin. The hybrid composite including 5 wt% calcined kaolin exhibited highly corrosion resistance to alkali and salty solutions compared to acidic reagents. Thermogravimetric analyses (TGA) and vicat softening temperature (VST) tests revealed that an important improvement was not observed in degradation temperatures of the hybrid composites; however, residue at 650 degrees C increased up to 21.0% in the presence of calcined kaolin. It can be said that the hybrid composites mentioned above came into prominence with high tensile strength, quite low water uptake and excellent corrosion resistance in alkali and salty environments. (C) 2017 Elsevier Ltd. All rights reserved.Öğe Sustainable nanocomposites of epoxy and silica xerogel synthesized from corn stalk ash: Enhanced thermal and acoustic insulation performance(ELSEVIER SCI LTD, 2018) Kaya, Gulcihan Guzel; Yilmaz, Elif; Deveci, HuseyinThe synthesis of silica xerogel from corn stalk ash in ambient pressure drying was carried out by sol-gel method. With the usage of silica xerogel (0.5, 1.0 and 1.5 wt%) in epoxy resin (ER), silica xerogel/epoxy nanocomposites were successfully prepared. The uniform dispersion of silica xerogel in neat ER was observed except nano composite including 1.5 wt% silica xerogel. The low density nanocomposites showed high thermal stability and low thermal conductivity. The char residue at 600 degrees C and thermal conductivity of nanocomposite including 1.5 wt% silica xerogel were specified as 20.30% and 0.220 W/mK, respectively. The acoustic velocity of the nanocomposites was decreased with increasing amount of silica xerogel. The water sorption of the nano composites was slightly higher than neat ER. The water contact angle of the nanocomposites were between 75 degrees and 70 degrees. The study provided a new thermal and acoustic insulation material instead of expensive and health risk traditional materials.Öğe The use of colemanite and ulexite as novel fillers in epoxy composites: Influences on thermal and physico-mechanical properties(ELSEVIER SCI LTD, 2016) Guzel, Gulcihan; Sivrikaya, Osman; Deveci, HuseyinBoron compounds such as colemanite, tincal and ulexite are of interest in many application areas due to their great properties. Colemanite and ulexite was used individually as fillers to prepare epoxy composites in this study. The influences of amount of filler, type of hardener and plasticizer addition on the properties of the novel composites were investigated with instrumental analyses and tests. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses showed good dispersion of filler in the epoxy matrix. Improvement in tensile properties was obtained up to 5 wt% filler content in the composites. Water sorption reduced dramatically with increasing amount of filler compared to neat epoxy. Excellent corrosion resistance and strong adhesion properties were observed in all composites. Thermogravimetric analyses (TGA) and vicat softening temperature (VST) tests indicated that colemanite had better synergistic effect on the thermal properties of the neat epoxy than ulexite. Resistance to cold environment of the composites was quite high. It was thought that the composites can be evaluated successfully with the mentioned advantages in many industrial fields such as construction, coating, flooring, and so on. (C) 2016 Elsevier Ltd. All rights reserved.
