An expansion temperature tolerant, dry, expandable sealant and baffle is provided which is capable of undergoing a desired degree of full expansion when an automobile body containing the sealant and baffle product is conveyed through a conventional bake and/or curing oven. The sealant and baffle product is fully expandable over a wider temperature and time range than heretofore available expandable baffle products. The composition for preparation of a molded expandable sealant and baffle component includes a grafted anhydride polymer, an epoxide terminated additive polymer which are capable of reacting with the grafted anhydride polymer and a blowing agent. The anhydride polymer and the epoxide terminated polymer react to a limited degree in the absence of a catalyst when the baffle product is heated in the bake and/or curing oven, thus providing an improved networked and bridged backbone polymer which effectively entraps gas emanating from the blowing agent, without adversely affecting the flexibility and expansion characteristics of the sealant baffles.