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Öğe Chemical and plasma surface modification of lignocellulose coconut waste for the preparation of advanced biobased composite materials(ELSEVIER SCI LTD, 2017) Kocaman, Suheyla; Karaman, Mustafa; Gursoy, Mehmet; Ahmetli, GulnareIn this study, surface-modified grinded coconut waste (CW) particles were used as bio-fillers to prepare polymeric composite materials with enhanced properties. Epoxy resin modified with acrylated and epoxidized soybean oil (AESO) was used as the polymer matrix. Two different strategies, namely chemical treatment and plasma enhanced chemical vapor deposition (PECVD) were utilized to modify the surface of CW particles for using them as compatible bio-fillers in composite preparation. Chemical modification involved the treatment of CW particles in a highly alkali NaOH solution, while PECVD modification involved coating of a thin film of hydrophobic poly(hexafluorobutyl acrylate) (PHFBA) around individual CW particle surfaces. Untreated and surface-modified CW particles were used in 10-50 wt% for preparation of epoxy composites. FTIR analysis was performed to study the effect of modification on the structures of particles and as-prepared composites. The composite morphologies were investigated by XRD and SE. TGA test was conducted to study the thermal behavior of the composites. Also, the effects of CW particle surface modification on the mechanical and water sorption properties of epoxy resin composites were investigated in detail. It was observed that PECVD-treated CW particles had much more positive effects on the thermal, mechanical, wettability and flammability properties of composites. (C) 2016 Elsevier Ltd. All rights reserved.Öğe Effect of Modification with Various Epoxide Compounds on Mechanical, Thermal, and Coating Properties of Epoxy Resin(HINDAWI LTD, 2016) Cerit, Alaaddin; Marti, Mustafa Esen; Soydal, Ulku; Kocaman, Suheyla; Ahmetli, GulnareEpoxy resin (ER) was modified with four different epoxide compounds, 4,5-epoxy-4-methyl-pentane-2-on (EMP), 3-phenyl-1,2-epoxypropane (PhEP), 1-chloro-2,3-epoxy-5-(chloromethyl)-5-hexene (CEH), and a fatty acid glycidyl ester (FAGE), to improve its chemical and physical properties. The effects of the addition and amount of these modifiers on mechanical, thermal, and coating properties were investigated. Atomic force microscopy was used to observe the changes obtained with the modification. The influence of the modifying agents on the curing process was monitored through FTIR spectroscopy. The curing degrees of ER and modified ERs (M-ERs) were found to be over 91%. The results showed that tensile strength of ER improved till 30% (wt.) with addition of the modifier content. Modification with EMP and PhEP remarkably enhanced the thermal stability of ER to be highly resistant to the corrosive media.Öğe Epoxy composites based on inexpensive char filler obtained from plastic waste and natural resources(WILEY, 2013) Ahmetli, Gulnare; Kocaman, Suheyla; Ozaytekin, Ilkay; Bozkurt, PinarIn this study, plastic [polyethylene terephthalate (PET)] waste was recycled as raw material for the preparation of diglycidyl ether of bisphenol A-type epoxy composite materials. The other inexpensive fillers used to prepare the composites were wood shavings char and pine cone char (PCC), obtained from natural resources. The thermogravimetric analysis showed that plastic waste char (PWC) and PCC can significantly improve the thermal stability of neat epoxy resin at temperatures above 300 degrees C. The best thermal and electrical conductivity results were obtained with PWC. The residual weight of the composite with 30 wt% PWC was 69%. Surface hardness, Young's modulus, and tensile strength of the composites were higher than those with a pure epoxy polymer matrix. The composite morphology was characterized by X-ray diffraction and scanning electron microscopy. POLYM. COMPOS., 2013. (c) 2013 Society of Plastics EngineersÖğe Epoxy Composites based on Inexpensive Tire Waste Filler(AMER INST PHYSICS, 2014) Ahmetli, Gulnare; Gungor, Ahmet; Kocaman, SuheylaTire waste (TW) was recycled as raw material for the preparation of DGEBA-type epoxy composite materials. The effects of filler amount and epoxy type on the mechanical properties of the composites were investigated. Tensile strength and Young's modulus of the composites with NPEL were generally higher than composites with NPEF. The appropriate mass level for TW in both type composites was found to be 20 wt%. The equilibrium water sorption of NPEL/TW and NPEF/TW composites for 14-day immersion was determined as 0.10 % and 0.21 %, respectively. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used for characterization of the composites.Öğe Evaluation of sugar mill lime waste in biobased epoxy composites(WILEY, 2018) Soydal, Ulku; Marti, Mustafa Esen; Kocaman, Suheyla; Ahmetli, GulnareIn this study, precipitated calcium carbonate-lime waste (LW) from sugar beet production was recycled as a raw material for the preparation of composite materials. Epoxidized soybean oil (ESO) was used as a co-matrix in 50 wt% with bisphenol A-type epoxy resin (ER). The composites were prepared with LW in varied per cent values (10-50 wt%) using the casting technique. The morphology of the composites was characterized by X-ray diffraction and scanning electron microscopy. Effects of ESO and LW amounts on the mechanical and thermal properties of the composites were investigated. Modification with ESO remarkably enhanced the plasticity of the material, but decreased the curing degree about 2%. The modified ER shows about 13% increase in elongation at break over the pure epoxy matrix. Density and hardness of neat epoxy matrices were observed to increase with the LW content in the composite. Tensile strengths of all composites are higher than that obtained with neat epoxy. The thermogravimetric analyses show that ESO and LW significantly improve the thermal stability of neat ER at the temperatures above 300 degrees C. The best thermal results were obtained with the composites containing 40- and 50 wt% LW. The residual weights of the composites are higher than that of neat ER and ER-ESO, and increases with the increasing LW amount. The T-5,T- T-10 and T-50 data of the composites are higher than those of neat ER and ER-ESO. The water sorption values of the ER-ESO matrix composites are in the range of 1.0-2.9 wt%. POLYM. COMPOS., 39:924-935, 2018. (c) 2016 Society of Plastics EngineersÖğe The Influence of Semiconductive Binary Sb2S3-Yb3S4 System on Electrical Conductivity Property of Epoxy Composites(AMER INST PHYSICS, 2014) Soydal, Ulku; Ahmetli, Gulnare; Kocaman, SuheylaThe purpose of this study is to develop the semiconductive composites. Semiconducting glass (SG) binary system Sb2S3-Yb3S4 in mole ratio 1:1 was synthesized and was doped with I-2. Next, electrically conductive DGEBA-type epoxy resin (ER)/SG-filled composites and epoxy toluene oligomer (ETO) modified epoxy resin-SG filled composites were developed with 3-10 wt. % of fillers and characterized. As a result, the effects of the modifier and amount of semiconductive filler on the electrical properties of commercial epoxy resin were examined. Percolation concentration was 7 wt. % for all composites. For the SG-reinforced composites, the dispersion of the fillers is investigated by X-ray diffraction (XRD) and by scanning electron microscopy (SEM).Öğe A study of coating properties of biobased modified epoxy resin with different hardeners(ELSEVIER SCIENCE SA, 2016) Kocaman, Suheyla; Ahmetli, GulnareIn this study, acrylated soybean oil (AESO) was used as a modifying agent for DGEBA-type epoxy resin (ER). The structure of modified epoxy resins (M-ERs) cured with various hardeners (SAc-sebacic acid, MNA-methyl nadic anhydride, PhA-phthalic anhydride, MA-maleic anhydride, SA-succinic anhydride, cycloaliphatic polyamine Epamine PC 17, MXDA-m-xylenediamine, MI-2-methylimidazole and polyamide type Crayamid) were characterized by Fourier transform infrared spectroscopy (FTIR). Atomic force microscopy (AFM) and SEM were used to determine the microstructures of some M-ERs. DSC test was conducted to study the effects of hardners on the Tg of the M-ERs. The influence of the modifying agent and hardeners on the curing process was studied through FTIR spectroscopy, and the curing degrees of M-ERs were determined to be over 94%. To investigate the effects of the curing agents, a comparative study was also performed on the mechanical properties of neat ER, such as the tensile strength and hardness. Comparison between the mechanical properties of the epoxy systems demonstrated that the neat ER system had a higher tensile strength and e-modulus than that of M-ERs, which is in contrast to the elongation at break. Higher tensile strength values of 58 MPA and 53 MPa were observed for M-ERs cured with MNA and MXDA curing agents, respectively. A comprehensive study of the mechanical and water sorption properties of M-ERs illustrated that for an epoxy system modified with AESO in 50 wt%, MNA and MXDA were a more effective hardeners. Coatings obtained from M-ERs cured with anhydride type hardeners were determined to be highly resistant to acidic corrosive media. (C) 2016 Elsevier B.V. All rights reserved.Öğe Study on the reuse of marble and andesite wastes in epoxy-based composites(WILEY, 2018) Soydal, Ulku; Kocaman, Suheyla; Marti, Mustafa Esen; Ahmetli, GulnareAndesite- (AW) and marble-dust wastes (MW) were recycled to be used in composite preparation. Both were obtained from local industrial sources. Commercially available epoxy resin (ER) and its modified version with polyaniline (PANI) were used as the neat polymer matrix. The dispersion of the fillers was investigated by X-ray diffraction and scanning electron microscopy. The effects of PANI and waste loading on the mechanical, thermal, electrical, water sorption, and corrosion properties were investigated. The optimum loading levels for MW or AW in the composites were found to be 20 wt%. Using thermogravimetric analyses, thermal behavior and stability of the composites prepared were probed. The incorporation of PANI and waste fillers increased the T-10 temperature by 10-33 degrees C and the tensile strength by 4-51 MPa of neat ER. The composites containing 10-30 wt% AW filler were found to be semiconductive and electrical conductivity decreased with the increase in AW content. The PANI-ER/AW composite showed perfect resistance to corrosion and also exhibited the best adhesion. POLYM. COMPOS., 39:3081-3091, 2018. (c) 2017 Society of Plastics EngineersÖğe Synthesis and characterization of UV-crosslinkable unsaturated ketone group containing polystyrene films(ELSEVIER SCIENCE SA, 2013) Ahmetli, Gulnare; Cerit, Alaaddin; Kocaman, SuheylaIn this study, as a serial of our previous studies, polystyrene (PS) containing acetyl group (CH3CO-) was used as a raw material and condensation reaction was performed in basic medium with aliphatic saturated and unsaturated aldehydes. Synthesized modified polystyrenes (MPSs) were characterized using spectroscopic (H-1 NMR and IR) and chemical analysis methods. Atomic force microscopy (AFM), has been used to determine the microstructure of PS, APS and MPS with crotonaldehyde, as example. The thermal properties of polymers were investigated after crosslinking by ultraviolet (UV) irradiation. The crosslinking of MPSs was quantitatively estimated from the amount of insoluble polymer as well as the change in the glass transition temperature. As a result, MPSs with crotonaldehyde and cinnamaldehyde had higher thermal properties and crosslinking than others due to two double bonds in their structure. MPSs films were resistant to corrosive mediums. After irradiation, water sorption of MPS decreased 0.65%. (C) 2013 Elsevier B.V. All rights reserved.
