The effects of pH value of reaction system, reaction time, reaction temperature, bromine concentration, and amount of potassium persulfate on the bromination reaction in the preparation of brominated natural rubber (BNR) from natural rubber latex were discussed. It has been found from the thermal analysis, that is, the thermal degradation of BNR in nitrogen is a two-step reaction, and 16% carbonide with a stable structure remained at 470-650 degrees C. The thermo-oxidative degradation of BNR in air is also a two-step reaction, and the percentage of degraded BNR reaches to nearly 100% at 600 degrees C. (c) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 25 29, 2010