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 .