Ultrasonic Activation of PIM-1 Synthesis and Properties of Polymers Obtained by Precipitation Polyheterocyclization in Dimethyl Sulfoxide

A new method for activating the synthesis of high molecular weight polymer PIM-1 obtained in dimethyl sulfoxide is proposed and studied. A simple and technologically effective process of precipitation polyheterocyclization occurs at 60–80°C for 2–5 h under constant exposure to ultrasound at a frequency of 37 kHz. This method allows one to synthesize the PIM-1 polymer with a molecular weight of up to 121 × 103 and a relatively low polydispersity index of 3.8. In addition to powder materials, microporous nanofibrous materials are obtained by electrospinning from polymer solutions. According to the Brunauer–Emmett–Teller method, the specific surface area of PIM-1 reaches 862 m2/g for powders and 362 m2/g for nanofibers.