Synthesis and Characterization of Polyphosphonates and Polyurethanes Using Chalcone and DOPO-Chalcone as a Flame Retardant

We synthesized a series of chalcone-based polyphosphonates and polyurethanes as self-extinguishing flame-retardant polymers and characterized them via FTIR, 1H, 13C, 31P NMR, HRMS, gel permeation chromatography, and inductively coupled plasma–optical emission spectrometry. The thermal stability of the synthesized polymer series was tested by thermogravimetric and evolved gas analysis under both N2 and air atmospheres as well as microscale combustion calorimetry analysis. After thermal treatment, residue analysis was carried out using scanning electron microscopy with energy-dispersive X-ray analysis and X-ray photoelectron spectroscopy, and decomposition mechanisms are proposed.