Effect of a novel polysiloxane-containing nitrogen on the thermal stability and flame retardancy of epoxy resins

A novel polysiloxane-containing nitrogen (PSiN) was synthesized, and it was added to epoxy resin (EP) as flame retardant. The structure of PSiN was characterized by Fourier transform infrared spectroscopy and H-1 NMR. The effect of PSiN on the flame retardancy and thermal behaviors of EP were investigated by limited oxygen index (LOI), microscale combustion calorimetry test (MCC) and thermogravimetric analysis (TG). The results showed that the flame retardancy and the thermal stability of EP were improved with the addition of PSiN. When 4.5 mass% PSiN was incorporated, the LOI value of EP was found to be 29 %, which is higher than 21 % of pure EP. The char structure observed by scanning electron microscopy (SEM) indicated that the surface of the char for EP100/DDM (4,4-diaminodiphenyl-methane) 20.7/PSiN4.5 system holds a smoother and denser char structure when compared with EP100/DDM21.8 and EP100/PSiN90 systems.