Preparation and thermal properties of a novel flame retardant copolymer

A monomer, acryloxyethyl phenoxy phosphorodiethyl amidate (AEPPA), was synthesized and characterized using Fourier transform infrared (FTIR), 1H nuclear magnetic resonance spectroscopy (1H NMR) and 31P NMR. The copolymer with various amounts of styrene (St) was obtained by the free radical bulk polymerization between AEPPA and St, and characterized using 1H NMR. The thermal properties of the copolymers were investigated with thermogravimetric analysis (TGA) in air and nitrogen atmosphere, and differential scanning calorimetry (DSC). The TGA results in air indicated the copolymers with AEPPA show higher thermal stability than those without AEPPA. However, the TGA results in nitrogen showed that the decomposition temperature decreased and the char residue increased with the increase of AEPPA. The glass transition temperature (Tg) of the copolymers from DSC indicated that a inverse proportion was observed between Tg and the amount of AEPPA incorporated. The flammability of the copolymers was evaluated by microscale combustion calorimeter (MCC). The MCC results showed that AEPPA can decrease the peak heat release rate (PHRR) and the heat release capacity (HRC), and the sample CP10 shows the lowest PHRR and HRC.