| abstract |
This invention relates to a thermally stable brominated polystyrene composition which contains alkali metal base (e.g., NaOH) in an amount less than about 1 wt.% such that if the flame retardant is dissolved in bromochloromethane and the resultant solution is extracted with water, the resultant water extract exhibits a pH of at least about 9.0. A preferred composition of this type even when heated to 315 °C for one hour did not undergo darkening - the color remained tan. Comparative samples not containing the base turned black under these same conditions. Especially useful compositions additionally have less than 500 ppm, and better still, less than 100 ppm total Cl, and at least about 67 wt.% bromine. Processes for producing the compositions are also described. |