The thermal stability of poly(sodium 4-styrenesulfonate) intercalated graphite oxide has been investigated using a differential scanning calorimeter. The poly(sodium 4-styrenesulfonate) intercalated graphite oxide composite shows a prominent exothermic reaction near 207 degrees C and an endothermic reaction near 453 degrees C. Graphite oxide is responsible for the exothermic reaction while the endothermic reaction is caused by the poly(sodium 4-styrenesulfonate) used in the synthesis of poly(sodium 4-styrenesulfonate) intercalated graphite oxide. The onset temperature of the exothermic reaction of poly(sodium 4-styrenesulfonate) intercalated graphite oxide decreased by 92 degrees C in comparison with that of graphite oxide, indicating the addition of poly(sodium 4-styrenesulfonate) in the composite has diminished the thermal stability of graphite oxide. (C) 2011 Elsevier B.V. All rights reserved.