The New Polycyclotriphosphazenes: Synthesis, Characterization, Thermal and Photophysical Properties

Polyamides are used as high-performance materials in industry and electronics. Researchers have recently been focusing on this area and trying to synthesize more stable and high-performance molecules by polymerizing various groups into the backbone skeleton. In this work, we report the design, synthesis, and characterization of paracetamol derivatives of cyclotriphosphazene (DSPCT and DSHY) and polycyclotriphosphazenes (DSTPC and DSAC) for the first time. The structures of new products were fully characterized by MALDI-TOF Mass analysis, FT-IR, 1H and 31P NMR spectroscopies and single crystal X-ray (for DSPCT and DSHY) crystallography. The crystallization behaviours of the polyamides were studied by X-ray diffraction, and a scanning electron microscope was used to observe the morphology of the DSTPC and DSAC. Thermal degradation properties for DSHY, DSTPC and DSAC were determined by DSC and TGA techniques. Polyamides and the DSHY compound exhibited superior thermal stability with an initial decomposition temperature range of ca. 251-302 °C. Additionally, spectral characterization and photophysical behaviours (fluorescence quantum yields and lifetimes) of the all new compounds were also comprehensively investigated using UV–Vis and fluorescence spectroscopies (steady-state and time-resolved fluorescence).