Synthesis of brominated flame retardants with different brominated structures and study on flame retardancy of polystyrene resin

Brominated flame retardants can be divided into aromatic brominated flame retardants and fat brominated flame retardants. In this paper, six kinds of polymers with different bromine structures were synthesized, Includes two aromatic bromine structure polymers polytribromophenyl acrylate (PTrA) and Poly 2, 6-dibromophenyl ether (PBO),two adipose bromine polymer tribromoneopentyl polyacrylate (PBVT) and Polybromoethyl acrylate (PBBT), two aliphatic bromine aromatic bromine mixed polymer tribromoethyl acrylate (BCB) and fatty bromine aromatic bromine copolymer (BCVB). The effects of different bromine structure flame retardants on flame retardancy of polystyrene were investigated from the aspects of thermal stability, compatibility and molecular weight. Furthermore, the flame retarding mechanism of BCB and its effect on the mechanical properties of polystyrene were elucidated. The results showed that there was a negative correlation between molecular weight and flame retardancy. And the advantage of aliphatic bromine is that the thermal decomposition temperature is lower than that of aromatic bromine, bromine is released earlier, which can block the flame spread in the early stage of combustion. The poor thermal stability of the flame retardant will lead to its decomposition at 200. However, polystyrene processing is at this temperature, which resulted in reduced flame retardant performance. Moreover, aromatic structure had the advantage of better compatibility with polystyrene. BCB has the best flame retardant performance, and the limiting oxygen index (LOI) value is 24.5% under 15% addition, PHRR and THR were reduced to 670 kW/m2 and 63 MJ/m2. Meanwhile, the tensile strength, bending strength and impact strength of PS/BCB composites (15% BCB content) were decreased respectively 19.7%, 6.4% and12.2%. BCB plays a flame retardant role in the gas phase.