Abstract:

To enhance the flame retardancy and smoke suppression performance of EP-CE composites, a novel flame retardant was synthesized using DOPO and BPS as raw materials. The flame-retardant DOPO-BPS/OSEP/EP-CE composites were fabricated by the solution casting method, where DOPO-BPS and OSEP were jointly introduced into EP-CE matrix. Based on Fourier transform infrared spectroscopy (FTIR) analysis, nuclear magnetic resonance (NMR) analysis, thermogravimetric analysis (TGA), limiting oxygen index (LOI) test, UL-94 vertical burning test, and cone calorimeter analysis, the effects of different ratios of DOPO-BPS and OSEP on the flame retardancy and smoke suppression properties of EP-CE composite materials were studied. The results show that the phosphaphenanthrene ring structure of DOPO-BPS could form a stable carbon layer and block the transfer of heat and oxygen. The synergistic effect with OSEP significantly improves the flame retardant effect and smoke suppression performance. When the flame retardant DOPO-BPS and OSEP are added to EP-CE at a mass fraction of 9∶1, the flame retardant performance and smoke suppression performance are the best, the flame retardant performance reaches V-0 level, and the LOI increases to 31.4%. Compared with EP-CE, the peak heat release rate, total heat release and total smoke production decrease by 29.7%, 32.2% and 32.7%, respectively.

Key words: epoxy resin (EP), cyanate ester resin (CE), 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO), bisphenol sulfone (BPS), organic sepiolite (OSEP), flame retardancy, composite materials