itaconic anhydride, vinyl acetate, vinyl toluene, and acrylates such as methacrylate, methyl methacrylate, ethyl acrylate, etc.The foamable mixtures which are extruded and foamed in accordance with the process of the present invention contain a major amount of a styrenic polymer having a low melt index and a minor amount of a styrenic polymer having a high melt index.