Ultrasound and Pressure Assisted Solid-State Polymerization of Carbazole

This study was carried out with the aim of obtaining polycarbazole (PCz) with solid-state polymerization by using ultrasound and pressure assisted methods. For ultrasound-assisted method (U), first, the optimum carbazole (Cz) and cerium ammonium nitrate (CAN) amounts, polymerization time, ultrasound application conditions were determined and then the polymers that are called “PCz-U#” were characterized by using scanning electron microscope (SEM), fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), transmission electron microscobe (TEM), X-ray diffraction (XRD) and four-point prop conductivity measurements. The effect of the applied pressing time during preparation of pellet on the conductivity of PCz-U was also investigated. Pressure-assisted polymerization (P) was carried out at these optimum conditions and the resulting polymer was called “PCz-P#”. In order to understand the advantage of the ultrasound and pressure assisted methods, conventional polymerization in a solution was also performed at the optimum concentrations of Cz and CAN and the properties of PCz's obtained from three different methods were compared. The conductivities of PCz's obtained in a very short time such as one minute with the ultrasound and pressure assisted methods are at the same level as the conductivity of the polymer (∼10⁻⁴ S/cm) obtained by the solution method in 20 minutes using 16 and 35.6 times higher amounds of Cz and CAN, respectively. With this study, two new methods for PCz synthesis have been proposed, which are suitable for VOC limitation as no solvent is used in and environmentally friendly because less chemicals are used.