2022 Volume 43 Issue 5 Pages 189-197
The effect of polyethersulfone (PES) blend with bisphenol E dicyanate (DCBE) on the flame resistance of the cured resins was investigated. The DCBE/15 wt% PES blend compositions were cured at 200 ℃ using three different temperature ramps. The size of phase structure via reaction-induced phase separation and the glass transition temperatures (Tgs) of the two phases varied with the temperature ramps. The slower temperature ramps resulted in smaller phase structure sizes and closer Tgs of the two phases. When the phase structure size was in the middle (about 10 μm), the self-extinguishing time was the shortest and the flame resistance was the highest among them. When the phase structure size was large (20－40 μm), debonding at the interface of the phases occurred upon ignition, resulting in a decrease in flame resistance. On the other hand, when the phase structure size was small (2－3 μm) also, the flame resistance was lower than that of the middle size. This suggested that the role of the PES-rich phase as a flame retardant domain was reduced due to increased incorporation of DCBE components in the PES-rich phase.
