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- MakaleAçık Erişim2023Scopus SJRQ3Investigation of thermophysical properties of synthesized SA and nano-alumina reinforced polyester composites
Şahal, Hakan; Aydoğmuş, Ercan; Arslanoğlu, Hasan
Synthesis and characterization of 4-[(E)-(5-bromo-2-hydroxybenzylidene) amino]-N-(4-methylpyrimidin-2-yl) benzenesulfonamide (SA) has been performed. Alumina (Al2O3) and SA reinforced polyester composites are synthesized, and characterization processes are carried out. SA formed has been characterized by Fourier transform infrared (FTIR) spektrofotometre and nuclear magnetic resonance (NMR) spectroscopy. The thermal decomposition behavior of the nanocomposites in a nitrogen environment under non-isothermal conditions from 298 to 973 K is investigated with proportional-integral-derivative (PID) system. Thermal conductivity, Shore D hardness, and thermal decomposition behaviors of the nanocomposites that are added with alumina filler and synthesized with SA reinforcement have been compared. Nano-alumina filler raises the thermal conductivity coefficient and Shore D hardness of the polyester composites. The addition of synthesized SA reduces both the thermal conductivity coefficient and Shore D hardness. The thermal conductivity coefficient has been measured at the lowest in the pure polyester (0.056 W/m·K), and highest in the nano-alumina reinforced composite (0.072 W/m·K). The lowest Shore D hardness (nearly 68) is determined in the synthesized SA reinforced composite. Also, the experimental study has been optimized with the help of response surface methodology (RSM), and the improved theoretical models have been evaluated by statistical analysis.
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İncele - MakaleAçık Erişim2020Scopus SJRQ2Thermal studies and influence of the thermal decomposition on dielectric properties of a new coumarin copolymers
Biryan, Fatih; Pihtili, Güzin; Demirelli, Kadir
In this study, firstly 7-hydroxy-4-chloroethyl coumarin compound was synthesized in accordance with the literature (Peterson et al. in Macromol Chem Phys 202: 775–784, 2001). Then, this compound was reacted with acryloyl chloride to form the 4-(chloromethyl)-2-oxo-2H chromen-7-yl-acrylate) monomer. A series of copolymers were prepared using this monomer and n-butyl acrylate monomer. TGA analysis system was used to examine the thermal properties of homopolymers and copolymers. The activation energies were calculated for thermal decomposition of homopolymer and certain copolymers according to Flynn–Wall–Ozawa method. TGA measurements were taken at different heating rates and given comparatively. The glass transition temperatures of the copolymers were determined by DSC analysis and these results were given comparatively. For investigating the dielectric properties of copolymers, dielectric constant, dielectric loss factor, and ac conductivity values were calculated in the range of 100 Hz–20 kHz frequencies. The results were plotted as a function of frequency. In addition, dielectric behaviors of residues were determined after heating to the first decay temperature of the two-stage decay polymers and compared with the first states.
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