The invention is directed to pellets of unadulterated brominated anionic styrenic polymer having the following characteristics: A) a bromine content of at least about 50 wt%; B) an average crush strength in the Crush Strength Test of at least about 28 pounds per square inch; C) a particle size range in which at least about 70 wt% of the pellets are retained on a standard US No. 40 sieve and no more than about 30 wt% are retained on a standard US No. 5 sieve, which pellets can be prepared by brominating at least one anionic styrenic polymer having a GPC weight average molecular weight (Mw) in the range of about 2000 to about 200,000 and a GPC polydispersity in the range of 1 to about 2. Further, the invention is directed to pellets of unadulterated brominated styrenic polymer wherein the unadulterated brominated styrenic polymer is prepared by brominating at least one free-radically produced styrenic polymer having a GPC weight average molecular weight (Mw) in the range of about 30,000 to about 500,000 and a GPC polydispersity in the range of 1 to about 10, and wherein the brominated styrenic polymer formed in said process has a bromine content of at least about 50 wt%.