BROMINATED POLYSTYRENE HAVING IMPROVED THERMAL STABILITY AND COLOR AND PROCESS FOR THE PREPARATION THEREOF

摘要

In a process for the suppression of backbone halogenation during the bromination of polystyrenes comprising the step of pretreating a solution of a polystyrene reactant comprising from about 5 to about 20 percent by weight of a polystyrene reactant, in a halogenated hydrocarbon solvent with at least about 0.1 percent by weight of an additive to suppress halogenation of the polystyrene backbone prior to brominating the polystyrene in the presence of a catalyst; adding a metal halide bromination catalyst to the solution, capable of effecting bromination of the ring without causing cross-linking of the polystyrene; adding to the solution from about 1 to about 3.4 moles of a brominating agent, per mole of polystyrene repeating units; reacting the polystyrene reactant with the brominating agent at a reaction temperature of from about -20 DEG C to about 50 DEG C, and isolating the brominated polystyrene. A brominated polystyrene is also provided having a backbone halogen content of less than about 750 ppm and, a DELTA E color as low as about 5.