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- MakaleAçık Erişim2026Scopus SJRQ1Preparation of Nanographene-Based Copolymer Nanocomposites: Thermal Decomposition Kinetic, Optical, and Electrical Behaviors
Barim, Esra; Demirelli, Kadir
The poly(4-methacryloyloxyphenyl-4'-methoxystyryl ketone-co-methyl methacrylate) [P(MPMESK0.25-co-MMA)] was synthesized using a free radical copolymerization method at 60 °C. The composition of the copolymer was estimated by 1H-NMR. The nanocomposites of P(MPMESK0.25-co-MMA)-loaded 9 and 11 wt% nanographene (NG) were produced using the ultrasonic homogenizer sonicator. The FT-IR, 1H-NMR, GPC, TGA, XRD, and SEM techniques were used to characterize the copolymer and composites. The thermal behavior of P(MPMESK0.25-co-MMA) partially heated up to 270, 310, 340, and 380 °C was investigated by FT-IR analysis. A six-membered anhydride ring in the copolymer backbone formed at 340 °C and higher temperatures. TG measurements were used to analyze the thermal decomposition processes of pure P(MPMESK0.25-co-MMA) and P(MPMESK0.25-co-MMA)/NG 11 wt% composite. Apparent activation energies for thermal decomposition of P(MPMESK0.25-co-MMA)/NG 11 wt% were determined using the Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods at a temperature range of 200 and 400 °C for a weight loss of approximately 70%. The average activation energies determined from the FWO and KAS methods were 86.3 and 80.3 kJ/mol, respectively. The dielectric and electrical behaviors of the P(MPMESK0.25-co-MMA) and P(MPMESK0.25-co-MMA)/NG 11 wt% composite were investigated at room temperature. The dc activation energy for dc conductivity of nanocomposite was calculated as 1.092 eV. Optical properties such as absorption, reflectance, refractive index, absorption edge, direct band gap of the copolymer, and composites were investigated from their optical examinations in the wavelength region of 200–800 nm. It was found that the optical energy gap values had shifted to the lower energies with the doping of NG.
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İncele - MakaleYalnız künye2024Scopus SJRQ2Synthesis, spectroscopic characterization and optical studies of poly(AN-co-St) composites with doped lanthanum (III) chloride for aerospace applications
Aydin, Handan; Torgut, Gülben
In this study, firstly, the copolymer of acrylonitrile (AN) and styrene (St) was synthesized by solution polymerization method using 2,2′-azobisisobutyronitrile (AIBN) as an initiator. The composites of copolymer incorporating lanthanum (III) chloride (3, 6, 9 and 18 wt%), the rare earth element (REE), were prepared and thin films were produced by thermal evaporation method for optical measurement. The samples were characterized by attenuated total reflectance Fourier transform infrared (ATR–FTIR), scanning electron microscopy–energy dispersive spectroscopy (SEM–EDS) and X-ray diffraction (XRD). The glass transition temperature, which is one of the thermal properties of the synthesized copolymers and composites, was examined with a differential thermal analyzer. The changes in the optical properties of the samples produced with LaCl3 dopant were investigated using the UV–VIS spectroscopy. The optical band gaps of the samples were calculated using Tauc equation. As a result of the optical studies, it was observed that there was a change in the conductivity properties of the samples with the addition of LaCl3. The present results showed the advantage of using LaCl3 as a filler to improve the optical properties of poly(AN-co-St) samples.
- MakaleAçık Erişim2022Scopus SJRQ2Synthesis, characterization, and evaluation of antimicrobial performance of N-[3-(dimethylamino)propyl]methacrylamide based copolymer on pathogens
Pıhtılı, Güzin; Erecevit Sönmez, Pınar; Biryan, Fatih; Torğut, Gülben
In this study, poly{N-[3-(dimethylamino) propylmethacrylamide-co-acrylonitrile}; [P(DMAPMA-co-AcN)] copolymer was polymerized by free radical polymerization (FRP) in the presence of azobisisobutyronitrile (AIBN) initiator at 60°C. The structure of the synthesized polymer was characterized by the Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) methods. The bactericidal and fungicidal effects of the solutions prepared by adding methanol to this copolymer to prevent the growth of pathogenic bacteria, yeast, and fungi were evaluated by disk diffusion and broth microdilution method. Since the resistance of bacteria, yeast and fungi, which adversely affect human health, to antibiotics is an important issue, and there has not been any study on the antimicrobial properties of this copolymer, it has directed us to investigate its antimicrobial properties. According to antimicrobial susceptibility tests: The polymer solution showed a broad spectrum of antimicrobial action with 12.3–14.3 mm/inhibition zone diameter on Pseudomonas aeruginosa, Klepsiella pneumoniae, Enterococcus faecalis bacteria, Candida tropicalis, Epidermophyton floccosum yeast and fungi and showed a narrow spectrum of effect on inhibition of the growth of Candida albicans with 10.3 mm/inhibition zone diameter. No antimicrobial effects were observed on Staphylococcus aureus. The minimum inhibition concentration (MIC) value on the test microorganisms was determined as 125–31.25 μl. The data obtained prove that the polymer is in the same group as the interaction of bactericidal and fungicidal drugs. It is also important as a polymer with antimicrobial properties. This study aimed to produce a new polymer with antimicrobial properties. This polymer can be a new and yielding antimicrobial representative in different areas.
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İncele - 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 Erişim2022Scopus SJRQ4Molecular Structure, Vibrational, Spectral Investigation and Quantum Chemical DFT Calculations of Poly(N-isopropyl acrylamide-co-nbutyl methacrylate)
Pihtili, Güzin; Hekim, Seda; Pekdemir, Mustafa Ersin
A new copolymer poly(N-isopropylacrylamide-co-nbutylmethacrylate) was synthesized by free radical solution polymerization process using 2,2′-Azobis(2-methylpropionitrile) as an initiator in 1,4-dioxane at 70 °C. The structure of the copolymer was characterized by Fourier Transform Infrared Spectrometer (FTIR), the proton nuclear magnetic resonance (1H NMR), and the ultraviolet-visible spectroscopy (UV-vis) method. Theoretically, density functional theory (DFT) (B3LYP) was utilized to identify the molecular geometry and then examine the vibrational frequencies and electrical characteristics of this molecule, with the 6-31G basis set in the ground state. In dichloromethane solution, UV-vis spectra of the molecule were calculated using the Time-Dependent DFT method. 1H NMR chemical shifts have been calculated with GIAO approximation, and the calculated results show good agreement with experimental chemical shifts.
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