Synthesis and characterization of 2,2,2-trifluoroethyl methacrylate / n-vinylcarbazole copolymer and investigation of the thermal and dielectric behaviors of its graphite-reinforced composites

In this study, a copolymer containing 2,2,2-trifluoroethyl methacrylate (TFEMA) and N-vinyl carbazole (NVC) was synthesized using the free radical polymerization method. The structural characterization of the obtained P(TFEMA-co-NVC) copolymer was performed using proton nuclear magnetic resonance (¹H-NMR) and Fourier transform infrared spectroscopy (FT-IR) techniques; the composition ratio was calculated using ¹H-NMR spectra. Composites were prepared by adding graphite at 5% and 10% by weight to the copolymer, and the thermal properties of these structures were examined comparatively. According to thermogravimetric analysis (TGA) and differential thermal analysis (DTA) results, it was observed that the glass transition temperature of the copolymer increased with the increase in N-vinyl carbazole units. On the other hand, it was determined that the glass transition temperatures of the composites prepared with graphite additions in two different compositions decreased compared to the pure copolymer. The thermal decomposition kinetics of the P(TFEMA-co-NVC) copolymer and the composite containing 10% graphite were calculated using TGA data via the Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods. According to the FWO and KAS methods, the activation energies of the copolymer studied were found to be 278.925 kJ/mol and 282.52 kJ/mol, respectively, those of the composite containing 10% graphite were 261.53 kJ/mol and 264.23 kJ/mol, respectively. Additionally, the dielectric behavior of copolymer and graphite-reinforced composites was investigated at different frequencies; it was found that the dielectric constant of the composites increased with an increase in the graphite content.