polymer foams are extensively used in the packaging industry and as thermal insulation, buoyancy aids and structural elements in sandwich composites,because they are low density materials with relatively high strength and stiffness per unit weight,as well as high damage tolerance(1-3).the integration of polymer chloride(pvc)and other foams into sandwich structures heavily relies on the availability of detailed studies relating their microstructure with their durability and mechanical properties(4-6)