Preparation of beta-CD@ferrocene@hollow mesoporous silica microsphere and investigation of its flame retardant EP

For improving the flame retardancy of epoxy resin (EP), beta-cyclodextrin@ ferrocene@hollow mesoporous silica microspheres (beta-CD@FE@HMS) were prepared successfully by the self-assembly method. Then, they were used as flame retardant to improve the fire safety of EP. EP/beta-CD@FE and EP/HMS composites were also prepared for comparative study. The results showed that beta-CD@FE@HMS could effectively improve the thermal stability of EP, in which the initial degradation temperature and the amount of char residue of EP were increased. The content of small molecule toxic gases produced by the combustion of EP composite was also reduced apparently. With the addition of 5 wt% beta-CD@FE@HMS, LOI value of EP was increased to 27.5% from 19.8%, and UL-94 reached V-1 rating. Comparing with pure EP, the peak heat release rate and total heat release values of EP were reduced by 11.0% and 12.3%, respectively, and the total smoke production was reduced by 30.6%. EP/beta-CD@FE@HMS composite formed a higher quality char layer. Therefore, beta-CD@FE@HMS microspheres could improve the fire safety of EP.