Preparation of polyethylene-octene elastomer/clay nanocomposite and microcellular foam processed in supercritical carbon dioxide

Polyethylene-octene elastomer (POE)/organoclay nanocomposite was prepared by melt mixing of the POE with an organoclay (Cloisite 20A) in an internal mixer, using poly[ethylene-co-(methyl acrylate)-co-(glycidyl methacrylate)] copolymer (E-MG-GMA) as a compatibilizer. X-ray diffraction and transmission electron microscopy analysis revealed that an intercalated nanocomposite was formed and the silicate layers of the clay were uniformly dispersed at a nanometre scale in the POE matrix. The nanocomposite exhibited greatly enhanced tensile and dynamic mechanical properties compared with the POE/clay composite without the compatibilizer. The POE/E-MA-GMA/clay nanocomposite was used to produce foams by a batch process in an autoclave, with supercritical carbon dioxide as a foaming agent. The nanocomposite produced a microcellular foam with average cell size as small as 3.4 mu m and cell density as high as 2 x 10(11) cells cm(-3). (c) 2005 Society of Chemical Industry.