Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Barım, Esra(4)
- Demirelli, Kadir(4)
- Tuncer, Hülya(4)
- Kök, Mediha(3)
- Pekdemir, Mustafa Ersin(3)
- Barim, Esra(2)
- Dere, Ayşegül(2)
- Dogan, Akar(2)
- Kanca, Muhammed Sait(2)
- Taşgın, Yahya(2)
- Torğut, Gülben(2)
- Yılmaz, Demet(2)
- Özen Öner, Ecem(2)
- Abubakar, Abdullahi Musa(1)
- Agar, Salih(1)
- Al-Ghamdif, Ahmed A.(1)
- Al-Sehemi, Abdullah G.(1)
- Ateş, Burhan(1)
- Aydın, Cihat(1)
- Aydın, Handan(1)
- Ayhan, Nagihan Karaaslan(1)
- Barım, Gamze(1)
- Biryan, Fatih(1)
- Canbay, Canan Aksu(1)
- Coğalmış, Fatma Tuba(1)
- Dik, Gamze(1)
- Doğan, Akar(1)
- Gundogdu, Emrah(1)
- Güler, Seval Hale(1)
- Güler, Ömer(1)
- Güneş, Çağdaş(1)
- Inci, Şule(1)
- Kanca, M. Sait(1)
- Karaduman, Oktay(1)
- Karaman, Altuğ(1)
- Kirbağ, Sevda(1)
- Mahmat, Aybars(1)
- Pekdemir, Sibel(1)
- Pihtili, Güzin(1)
- Selçuk Pekdemir, Sibel(1)
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ1Investigation of the structural, thermal and radiation shielding properties of (Er0.2Yb0.2Sm0.2La0.2Eu0.2)2Zr2O7 high entropy oxide reinforced tin matrix composite
Güler, Ömer; Yılmaz, Demet; Kanca, M. Sait; Kök, Mediha; Güler, Seval Hale; Taşgın, Yahya
This study investigates the structural, thermal, and radiation shielding properties of (Er0.2Yb0.2Sm0.2La0.2Eu0.2)2Zr2O7 high entropy oxide (HEO) reinforced tin (Sn) matrix composites. In the first stage of the study, HEO powders were synthesized by grinding at 350 rpm for 30 h using a solid-state method with mechanical alloying assistance, and then calcining at 1100 °C for 8 h. In the second stage, composites were produced by mixing HEO-reinforced Sn matrix materials containing 1%, 5%, and 10% reinforcement, pelleting them under 200 MPa pressure, and then sintering them at 300 °C for 3 h. In the first stage of the study, (Er0.2Yb0.2Sm0.2La0.2Eu0.2)2Zr2O7 HEO powders were synthesized using a mechanical alloying-assisted solid-state route. In the second stage, HEO-reinforced Sn matrix composites containing 1 wt%, 5 wt%, and 10 wt% reinforcement were produced. The phase formation and crystallographic structure of the synthesized powders and composites were characterized using X-ray diffraction. Thermal behavior and phase stability were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The thermal analysis results revealed dehydration and structural stabilization processes at intermediate temperatures, while crystallization of the HEO phase was observed at elevated temperatures. In addition, oxidation behavior of the Sn matrix composites was evaluated, showing that the presence of HEO particles significantly suppresses mass gain during high-temperature oxidation, indicating improved thermal stability. Finally, the radiation shielding performance of the samples was experimentally evaluated within the photon energy range of 59.54–609.2 keV using Am-241, Ba-133, and Ra-226 radioactive sources together with a Ultra-Low Energy Germanium (ULEGe) detector. The results demonstrate that the incorporation of HEO particles leads to minor, energy-dependent variations in the radiation attenuation capability of the tin matrix, influenced by the presence of high atomic number rare-earth elements and modified microstructural characteristics. The gamma radiation protection coefficient (RPC) values indicate strong attenuation in the low photon energy region, decreasing to approximately 16–19% at 609.3 keV. Moreover, the measured neutron equivalent dose rates increase from 0.054 µSv/h for pure Sn to 0.285 µSv/h for the Sn–10%HEO composite, indicating that HEO incorporation modifies the neutron interaction behavior of the Sn matrix composites.
- MakaleAçık Erişim2025EFFECT OF GRAPHITE AND MAX PHASE ON THE THERMAL AND DIELECTRIC PROPERTIES OF N-VINYL CARBAZOLE AND BENZYL METHACRYLATE COPOLYMER
Barim, Esra; Gundogdu, Emrah
In this study, the P(N-vinyl carbazole-co-benzyl methacrylate) copolymer was synthesized, characterized by FT-IR/1H-NMR spectroscopic methods, and its composition was calculated from 1H NMR spectra. Composites of the copolymer with four different ratios of graphite (GR) and MAX phase (Ti3AlC2) by weight were prepared to obtain functional and novel electronic components for energy storage applications. Scanning electron microscopy, X-ray diffraction analyses were performed for some samples. Differential scanning calorimetry, thermogravimetric analysis curves were used to determine the thermal behavior of the materials. It was concluded that the composite with the highest glass transition temperatures and thermal stability was the composite with 10wt%GR/10wt%MAX additive. The thermal degradation kinetics of the copolymer and the composite containing 10wt%GR/10wt%MAX were investigated by applying the Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) methods and it was found that the thermal degradation activation energy of the composite was lower than that of the polymer. The dielectric properties of the materials were investigated at room temperature and between 0.1 kHz and 5 kHz. At 1 kHz the dielectric constants of the copolymer and 10wt%GR-doped composite were found to be 2.22 and 12.31, respectively. The composites doped with 10wt%GR and 10wt%GR/10wt%MAX were confirmed to be semiconductors.
- MakaleYalnız künye2025Scopus SJRQ2Studies on the improvement of thermal, dielectric and optical properties of poly(2,2,2-trifluoroethyl methacrylate) by the addition of graphite oxide as fillers
Barim, Esra
In this study, poly(2,2,2-trifluoroethyl methacrylate) homopolymer (PTFEMA) was synthesized via free radical polymerization method, and its composites with graphite oxide (GO) were prepared to improve its dielectric and thermal properties. Thermogravimetric evaluation revealed that graphite oxide acts to limit thermal diffusion throughout the PTFEMA loaded graphite oxide (GO) composite, and hence, thermal stability of composites improved. While the initial decomposition temperature of pure PTFEMA was found to be 233°C from thermogravimetric analysis measurements, the initial decomposition temperature of PTFEMA containing 5 wt% graphite oxide was found to be 251°C. The glass transition temperatures of the composites increased from 76°C to 86°C due to the increase in the amount of graphite oxide added to PTFEMA. The dielectric properties of composites were investigated from 100 Hz to 10 kHz for different temperatures. While the dielectric constant, ε′, of pure PTFEMA at 1 kHz at room temperature was found to be 3.00, that of the PTFEMA containing 5 wt% GO was found 10.32. Therefore, graphite oxide doped PTFEMA composites may be suitable candidates for energy storage applications. The dc conductivity and dielectric loss factor of PTFEMA containing 5 wt% graphite oxide were seen to increase with temperature.
AtıfScopus1OpenAlex1
İncele - MakaleAçık Erişim2025Scopus SJRQ3Role of tungsten oxide (WO3) on thermal and optical properties of smart polymer composites
Aydın, Handan; Özen Öner, Ecem; Aydın, Cihat
Tungsten oxide, a versatile transition metal with numerous polymorphs and sub-stoichiometric compositions, containing inherent tunnels and oxygen vacancies, has become a current field of study due to its rich crystal structure, high electrochemical stability, easy accessibility, and environmental friendliness. Thus, the versatile structure of WO3-based materials makes them promising candidates for advanced applications. Our study aims to provide valuable insights into the performance of these materials used in various fields. The structural, optical, and thermal characteristics of PVC-PCL composites doped with tungsten oxide (WO3) were examined in this work. According to DSC research, the thermal characteristics of the polymer matrix were significantly impacted by the addition of WO3. The thermal stability was found to have increased based on the TGA measurement findings. XRD analyses revealed that as the doping rate increased, improved crystallinity was seen. According to SEM tests, the grain clusters are uniformly mixed and the tungsten oxide is evenly spread across the surface. The dopant reacted either chemically or physically with the polymer matrix, according to the ATR-FTIR spectra of PVC-PCL matrix nanocomposite films. An improvement in conductivity with an increase in dopant concentration was noted in the optical experiments. Thus, it can be stated that PVC-PCL composites doped with WO3 can be used in optoelectronic, various industrial, and biomedical application areas due to their structural, optical, and thermal properties.
AtıfScopus1WoS1OpenAlex1
İncele - MakaleYalnız künye2025Scopus SJRQ2Investigation of Mechanical Properties of Jute and Tea Waste-Reinforced Epoxy Composite Material Produced by Vacuum Assisted Resin Infusion Molding
Dogan, Akar; Mahmat, Aybars; Agar, Salih
Recently, the production of materials obtained from plant sources has been increasing due to their environmentally friendly and sustainable sources. Natural fibers and waste materials offer a remarkable alternative in composite production due to their biodegradability, low cost and renewability. In this study, composite materials were produced using hybrid Jute and industrial tea waste-reinforced epoxy materials by vacuum assisted resin infusion molding. In this context, the reason for using natural and industrial resources such as jute fiber and tea waste is to contribute to both the improvement of mechanical properties and the reduction of environmental impacts. It was observed that tensile and flexural strength decreased as the amount of tea waste increased. Conversely, the energy absorbed during the quasi-static punch shear and Charpy impact tests increased, unlike the tensile and flexural strength. Approximately 50% decrease was observed in the tensile strength of the 60% tea waste reinforced material compared to the pure jute composite material. In Charpy impact and quasi-static punch shear tests, a 5% increase in the energy absorbed in the 60% tea waste reinforced composite materials was obtained.
AtıfScopus2WoS1OpenAlex1İncele - MakaleAçık Erişim2025Scopus SJRQ2PCL/chitosan composite films enhanced with Bi2O3 in nuclear shielding applications: Irradiation resistance, thermal and structural properties
Yılmaz, Demet; Pekdemir, Mustafa Ersin; Dik, Gamze; Selçuk Pekdemir, Sibel; Ulu, Ahmet; Taşgın, Yahya; Ateş, Burhan
In this work, irradiation resistance, thermal, and structural characteristics of Bi2O3-reinforced poly ε-caprolactone/chitosan composites for nuclear shielding applications were studied. PCL/CTS/Bi2O3 composite films were prepared by using different amounts of Bi2O3 (0.5%–4.0% (w/v)). The radiation shielding parameters of the synthesized composite films were both experimentally and theoretically measured at the high energy region. The equivalent dose rates of the prepared film samples were measured using a fast neutron source. Also, to determine the irradiation resistance, the samples were irradiated with Am-241 and Co-60 sources for 30 days. The MFP values at 80.99 keV changed by approximately 61% in samples PCL/CTS and PCL/CTS/4% Bi2O3. The results show that Bi2O3 content increases the gamma shielding abilities in PCL/CTS films. According to TGA results, the thermal stability of the polymer composite films is increased by the addition of Bi2O3 to the PCL/CTS blend film. The results show that PCL/CTS composite materials can be used as protective coating materials for nuclear shielding. Highlights: PCL/CTS/Bi2O3 composite films were prepared by the solvent casting method. The thermal stability of the composite films increased by increasing the Bi2O3 amount. Bi2O3 increased the LAC and MAC values of the composite films. PCL/CTS/Bi2O3 composite films have a neutron shielding effect.
AtıfScopus5WoS5İncele - MakaleYalnız künye2024Scopus SJRQ2Mechanical and thermal properties of short banana fiber reinforced polyoxymethylene composite materials dependent on alkali treatment
Doğan, Akar; Güneş, Çağdaş
The present study aimed to develop a recyclable composite material based on a natural product, namely banana fiber, instead of synthetic reinforcement elements such as glass fiber or carbon fiber in thermoplastic matrix composites employed in many aspects of daily life. Polyoxymethylene (POM) thermoplastic was used as the matrix material. 3 %, 6 %, and 9 % by weight short natural banana fiber was used as reinforcement. Furthermore, the study improved the mechanical and thermal properties of the composite material with chemical improvements based on alkali treatment of banana fiber. Banana fiber and POM was initially mixed mechanically and then extruded at temperatures between 170 and 190 °C to obtain a homogeneous mixture. The mixture obtained by extrusion was initially cooled in the cooling pool and then passed through the crusher to obtain granules. These granules were pressed in plastic injection molds to obtain standard test samples. The ratio of reinforcement material and the variations in mechanical and thermal properties of the composites induced by the alkali treatment are presented in figures and tables. Furthermore, the changes in cross-sectional material images were examined with electron microscopy scans. The tensile and flexural strength of the material improved with alkali treatment.
AtıfScopus21WoS19OpenAlex20İncele - MakaleYayıncıda açık erişim2024Scopus SJRQ2Controlling of electro-optical properties of cobalt phthalocyanine formed single chain polymer: Sudan III and nanographene based its composites
Demirelli, Kadir; Barım, Esra; Tuncer, Hülya; Dere, Ayşegül; Canbay, Canan Aksu; Karaduman, Oktay; Al-Sehemi, Abdullah G.; Al-Ghamdif, Ahmed A.; Yakuphanoğlu, Fahretttin
The synthesis of poly[4-(4-vinylbenzyl)oxy)phthalonitrile-co-styrene] [P(VBOPN5 %-co-St)] was carried out by free radical polymerisation at 60 °C. The successful formation of a green coloured single-chain polymer molecule with the formation of cobalt phthalocyanine (SCP-CoPc) was performed at 140–150 °C in the presence of dilute cyclohexanol. The characterization of SCP-CoPc was confirmed by FT-IR and UV/vis spectroscopic techniques. The absorption filtration process of the SCP-CoPc polymer/Sudan III composite was investigated. The introduction of Sudan III into the SCP-CoPc polymer matric strongly affected the optical transmission spectrum of the composite films. The optical transmission measurements of the SCP-CoPc/Sudan III thin film show a high absorption in the visible region (400–800 nm). In the SCP-CoPc/Sudan III composites, the optical band gaps (Eg1 and Eg2) of each of its components has changed significantly. The Eg1 and Eg2 were found to be between 1.90 and 2.83 eV, respectively. Depending on the sudan III content, a wide range from 600 nm to 730 nm indicates complete absorption filtration. The dc electrical conductivity and dielectric behavior of the SCP-CoPc/Nanografene (NG) 6 wt% nanocomposite increased with increasing temperature. From the dc conductivity plot, the Ea values of I. and II. regions were found to be 0.75 eV and 0.27 eV, respectively and it was found that the calculated activation energy obeyed the Arrhenius relationship. The refractive index and the optical permittivity of SCP-CoPc/NG 6 wt% have been estimated.
AtıfScopus2OpenAlex3İncele - MakaleAçık Erişim2024Scopus SJRQ1Preparation of carbon dot/polyaniline composites as voltage based dielectric material for capacitor applications
Coğalmış, Fatma Tuba; Demirelli, Kadir; Barım, Esra; Ük, Nida; Ünlü, Caner; Şenkal, Bahire Filiz; Dere, Ayşegül; Tuncer, Hülya; Yakuphanoğlu, Fahrettin
Polyaniline-carbon dot (CD/PANI) composites were prepared via in-situ oxidative polymerization of aniline in the presence of carbon dots, with specific concentrations carefully controlled during synthesis. The composite was characterized using spectroscopic (FT-IR), morphological (TEM, SEM) and electrical methods. Impedance analysis was employed to investigate the transport behavior of charge carriers in the frequency range of 500 Hz to 10 MHz at 25 °C. This study provides a comprehensive analysis of the dielectric properties of the CD/PANI composite, including dielectric constant, dielectric loss, loss factor, AC conductivity, admittance, impedance, and Cole–Cole plots. The dielectric constant of the CD/PANI composite was 6.97 for 1 kHz at 0.5 V and 12.87 for 1 kHz at 5 V. The values indicate that the increase in the dielectric constant of nanocomposite with increasing voltage. This suggests that CD/PANI composite is a dielectric material whose dielectric constants are controlled by applied voltage. Notably, the dielectric constant increased with rising applied voltage and decreased with increasing frequency. Current-voltage (I-V) measurements revealed that the composite's dielectric parameters could be tuned by varying the applied DC voltage, suggesting its potential as a voltage-dependent dielectric (VDD) material for capacitor applications. Furthermore, the enhanced electrical conductivity indicates that the CD/PANI composite is a promising candidate for next-generation dielectric devices.
AtıfScopus7OpenAlex7İncele - MakaleAçık Erişim2024Scopus SJRQ3Influence of Congored on the Optical, Dielectric and Thermal Behavior of Polymethyl Methacrylate and Polyvinyl Chloride
Yıldırım, Turgay; Barım, Esra; Tuncer, Hülya; Demirelli, Kadir
Polymethyl methacrylate (PMMA)/Congo Red (CR) and polyvinyl chloride (PVC)/CR composite films were prepared on optical glass by the drop method for optical measurements and also prepared as tablets under pressure for dielectrical measurements. The optical transmission spectra measurements for PMMA and PVC film doped with CR showed a highly absorption in the ultraviolet-visible (UV-Vis) optical range (at 353 nm and 518 nm) and considerably blocking in broad visible range (190 nm–640 nm). PMMA/CR and PVC/CR composite films containing congo red at a concentration of 1 wt% showed maximum absorption bands at 290 nm and 416 nm, but their transmittance percentages were reasonably reduced compared to those of pure PMMA and PVC. Both of composites indicated high transmittances between 640 nm and 800 nm. The optical constants of the PMMA/CR and PVC/CR composite films such as optical band energy gaps (Eg) estimated using Tauc’s model, refractive index and reflectance (%) were calculated. UV–Vis, Fourier transform infrared spectroscopy (FTIR) and Thermogravimetry Analysis (TGA) measurements were used to confirm the breakdown of the -N = N- azo group bonds attached to the aromatic ring as a result of thermal decomposition of CR at 500 °C, and it was suggested that N2 gas was eliminated from the CR above 360 °C. The dielectric plots showed that the dielectric constant increased when the CR is doped up to 70 wt% in the polymer matrices. A further increase in the doping concentration of CR resulted in an increase of the dielectric constant. The dielectric constant decreased with an increase in the frequency for all of the samples. The ac (alternating current) conductivity values of PMMA and PVC showed an increase with increasing CR dopant in the polymer composites, while the ac conductivity values were found to be values between those of the pure polymers and CR.
AtıfScopus4WoS4OpenAlex5İncele - MakaleAçık Erişim2024Scopus SJRQ2Physical and shielding properties of Er2O3 rare earth oxide compound content on PCL/PEG blend
Taşgin, Yahya; Pekdemir, Mustafa Ersin; Yilmaz, Mücahit; Kanca, Muhammed Sait; Kök, Mediha
Rare earth elements (RRE), due to their unique magnetic, electrical, and optical properties, are an important group of elements demanded in many application areas from machine technology to the health industry. In this study, new composites were obtained by mixing Erbium oxide (Er2O3), one of the rare earth element oxides, into PCL–PEG blend, which is also an important material group, in different ratios. The characteristic functional groups of the obtained polymer blend/Er2O3 nanocomposites were determined by the ATR-IR, and as the erbium oxide ratio increased, characteristic peaks of the polymers in the blend as well as characteristic signals of the Er–O–Er bond were found. When the thermal behavior of the obtained composites was examined, it was observed that the polymer blend exhibited miscible blend properties and the melting temperature of the polymer blend increased as the Er2O3 ratio increased. In addition, it was determined that the thermal stability of the composite increased significantly. X-ray measurements of composites at room temperature support other measurement results. It was determined that the presence of Er-RRE oxide increased the crystal structure feature in the polymer blend composite. Gamma radiation shielding capabilities of polymer materials containing different erbium ratios were investigated by calculating shielding parameters such as half value layer (HVL), radiation protection efficiency (RPE), and mean free path (MFP). Cs-137 and Co-60 radioactive sources were used as gamma sources. According to the obtained measurement results, Erbium oxide increased the absorption property of the polymer composite material. Graphical abstract: [Figure not available: see fulltext.].
AtıfScopus26WoS28OpenAlex29İncele - MakaleAçık Erişim2023Scopus SJRQ2B2O3 reinforced polylactic acid/thermoplastic polyethylene glycol shape memory composites
Pekdemir, Mustafa Ersin; Kök, Mediha; Kanca, Muhammed Sait; Özen Öner, Ecem; Pekdemir, Sibel; Inci, Şule; Kirbağ, Sevda; Tatar, Beyhan
Recently, there has been a great demand for boron-containing compounds (BCCs) with unique biological properties. The demand for the use of these compounds not alone but as additives in composite materials is increasing day by day. In this study, the effect of adding B2O3 compound to the blend of PLA and PEG polymers, which is an important biocompatible shape memory polymer, was investigated. In order to examine the effect of increasing B2O3 additive on the thermal properties of PLA-PEG blend, it was determined by using a Differential Scanning Calorimetry (DSC) and thermogravimetric analyzer (TGA), and it was seen that while the melting temperature of PEG decreased, the melting temperature of PLA increased. In addition, when the thermal stability of the composites was examined, increasing of thermal stability was observed with the addition of B2O3 and a three-step degradation occurred. It was determined that the B2O3/PLA-PEG composite was homogeneous by taking X-ray measurements and SEM measurements. The antimicrobial property of the PLA-PEG blend improved with the increasing B2O3 contribution were observed from the antimicrobial activity measurements of the composite against 4 different bacteria. However, it was determined that the PLA-PEG blend preserved its shape memory effect with increasing diboron trioxide contribution.
AtıfScopus13OpenAlex16İncele - MakaleYalnız künye2023Scopus SJRQ2Antibacterial activity of novel synthesized chitosan-graft-poly(N-tertiary butylacrylamide)/neodymium composites for biomedical application
Yazdıç, Ferit Can; Karaman, Altuğ; Torğut, Gülben; Ayhan, Nagihan Karaaslan
In this present study, composites of chitosan-graft-poly(N-tertiary butylacrylamide) (CH-graft-poly(N‑tert‑BAAm)) copolymer, with Neodymium (Nd), an important rare earth element, were prepared by precipitation technique. Nd was successfully incorporated into the polymer of different weight percentages (0.5%, 1%, and 2%) without any degradation. The effect of neodymium additives on the structural, morphological, and antibacterial activities against gram-positive bacteria and gram-negative bacteria of the polymer was analyzed using various instrument techniques. X-ray diffraction (XRD) results together with Fourier Transform Infrared (FT-IR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) studies confirmed the morphology of Nd-doped CH-graft-poly(N‑tert‑BAAm) composites without any other impurities. The antibacterial effect of Nd was studied by adding it to the copolymer in a weight ratio of 0.5%–2%. The antibacterial effect of neodymium concentration on four different strains of bacteria was investigated: Escherichia coli (ATCC 25922) (E. coli), Pseudomonas aeruginosa (DSM 50071) (P. aeruginosa), Bacillus subtilis (DSM 1971) (B. subtilis), and Staphylococcus aureus subsp. aureus (ATCC 25923) (S. aureus). The antibacterial activities of the obtained composites were determined using the Agar Well Diffusion Assay Method. Experimental results show that Nd binds well to CH-graft-poly(N‑tert‑BAAm). Activity against E. coli, P. aeruginosa, B. subtilis, and S. aureus subsp. aureus creates a potential for pharmaceutical and biomedical applications.
AtıfScopus8WoS7OpenAlex8
İncele - MakaleYalnız künye2022Scopus SJRQ2Single and repeated low-velocity impact response of E-glass fiber-reinforced epoxy and polypropylene composites for different impactor shapes
Dogan, Akar
This study focuses on the effects of low-velocity impact (LVI) response of thermoset (TS) and thermoplastic (TP) matrix-based composites. In this study, the effects of the impactor shapes on the low-velocity impact response of the composite panels that produced from different matrix was investigated. Unidirectional E-glass fiber fabrics with an areal density of 300 g/m2 as reinforcement and epoxy matrix were used to produce TS composite. The vacuum-assisted resin infusion molding (VARIM) method was used to manufacture composite panels. The thermoplastic composites were manufactured with E-glass fiber-reinforced polypropylene prepregs. The tensile strength of TS matrix-based composites is higher than TP matrix-based composites that have the same fiber volume fraction. Despite being under the same impact energy, the TP specimens possess higher perforation threshold than TS specimens. The shape of the impactor significantly affected the perforation threshold. Besides, the impact number that caused perforation reduced dramatically in conical impactor. The repeated impact number that caused perforation is 36 for hemispherical (HS) impactor, but it is only 3 for conical impactor for polypropylene matrix-based composite. Moreover, a significant effect of fiber volumetric ratio on impact resistance was observed. The perforation threshold of glass fiber-reinforced polypropylene composites for 40% and 50% fiber volume fraction are 61 and 98 J, respectively. The perforation threshold of TP and TS specimens for HS impactor that has the same stacking sequence is 61 and 55 J, respectively.
AtıfScopus42WoS45OpenAlex44İncele - MakaleAçık Erişim2022Scopus SJRQ2Synthesis and characterization of N-(2-acetyl benzofuran-3-yl) methacryl amide and ethyl methacrylate copolymer/graphite oxide composites and study of their kinetic and electrical properties
Demirelli, Kadir; Barım, Esra; Tuncer, Hülya; Barım, Gamze; Abubakar, Abdullahi Musa
Copolymers of N-(2-acetylbenzofuran-3-yl) methacrylamide (BFMAA) and ethyl methacrylate (EMA) were prepared by radical copolymerization. The composition of copolymers was estimated by 1H-NMR spectroscopy. The composites of P(BFMAA39-co-EMA) [COP1] and P(BFMAA15-co-EMA) [COP2] loaded 18 wt% graphite oxide (GO) were prepared utilizing Ultrasonic Homogenizer Sonicator Processor. The FT-IR, DSC, TGA and SEM techniques were used in the characterization of the copolymers and composites. The thermal degradation behavior of COP1 was investigated by FT-IR studies of the partially degraded copolymer. And, this copolymer was able to form a four-member amide ring and imidization via intramolecular while being heated above 340 °C. Dynamic TG analysis under argon gas was used to investigate the thermal decomposition processes of pure COP1 and COP1/GO. Two degradation models including the Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose methods were used to determine the apparent activation energy of the copolymer and its composite for approximately 65% of thermal decomposition occurred between 200 and 400 °C. The results also showed that average activation energy between 111.69 and 134.25 kJ/mol was obtained. The estimated activation energy values make it possible to build a simpler approach to expose the thermal decomposition behavior of copolymer and its composite. Dielectric and electrical behaviors of the copolymer composites having a semiconductor behavior filled with graphite oxide (GO) were investigated. The activation energy values of P(BFMAA15%-co-EMA)[COP2]/GO 18 wt% and COP1/GO 18wt% from dc conductivities were 0.182 eV and 0.245 eV, respectively.
AtıfScopus6OpenAlex8İncele - MakaleAçık Erişim2021Influence of particle size, additive ratio and chemical structure of zinc borate on mechanical properties of poly(vinyl chloride)
İpek, Yeliz
Zinc borate (ZB) is a flame retardant and smoke supressant compound of boron. It is widely used to achieve flame resistant polymer composites. Poly(Vinyl Chloride) (PVC) is one of the commercially important polymers that is mostly used for cable insulating, windows, doors, pipes, floorings and toys etc.. On the other hand, PVC releases toxic gases during fire as decomposition products. Zinc borate addition is thought to be a solution for this problem. However, this solution leads a new problem. Zinc borate effects the mechanical properties of the PVC. In the present study, to optimize the contribution of zinc borate, with different formulations (2ZnO·3B2 O3·3.5H2 O and 4ZnO·B2 O3·H2 O), with different additive ratios (1% and 5% by weight) and different particle sizes (nano-sized and micro-sized) were added to the PVC structure and the mechanical and thermomechanical properties of each composite were investigated. Mechanical properties of composites were determined by tensile test, impact test, hardness test while thermomechanical behaviours were detected with dynamic mechanical analysis (DMA). In the perspective of mechanical strength of PVC-ZB composite, additive ratio of ZB was more effective than particle size and chemical formulation of ZB. The additive ratio more than 5% by weight can negatively affect the mechanical strength and quality of the PVC-ZB composite.
AtıfScopus2OpenAlex2
İncele - MakaleAçık Erişim2020Scopus SJRQ2Electrical properties of two-armed poly(Ɛ-CL-co-BMA) composites filled with bentonite
Pihtili, Güzin; Torğut, Gülben; Biryan, Fatih
The dielectric and electrical conductivity properties of two-armed poly(Ɛ-CL-co-BMA) copolymer and adding bentonite forms were studied. The effect of the bentonite was investigated at different quantities (%3wt, %6wt, %15 wt). The measurements were performed at frequencies between 100 Hz to 10 kHz at room temperature, and the dielectric permittivity (ε′), the dielectric loss factor (ɛ″) and conductivity (σac) were calculated. ε′ and ɛ″ increased with increasing bentonite content. In addition, changes of susceptance (B) and impedance (IZI) were examined at different frequencies ranging from 100 Hz to 10 kHz in order to investigate the effect of bentonite loading. As frequency increases, (B) increases linearly, whereas IZI decreases and remains constant at high frequencies. Two-armed copolymer synthesized using ring-opening polymerization (ROP) and Atom Transfer Radical Polymerization (ATRP) and its composites prepared with bentonite were characterized by FT-IR, 1H-NMR and SEM. Thermal behaviors were examined by TGA and DSC methods and the effect of bentonite was discussed.
AtıfScopus15WoS14İncele