Effect of clay dispersion on the cell structure of LDPE/clay nanocomposite foams

In this study, the effect of clay and its dispersion state on the cell morphology and foaming behavior of chemically crosslinked polyethylene (PE) foams were examined. In addition, the effect of foaming process on the clay morphology was also considered. It was shown that the morphology of the clay before the foaming process and its compatibility with PE matrix play a major role in determining the final foam properties. A PE‐g‐MA compatibilizer was used to increase the melt intercalation of PE onto the clay galleries and to improve clay dispersion in the PE matrix. The uniform dispersion of clay provided greater and well‐ dispersed nucleation sites. This led to smaller cell size, narrower cell size distribution, and higher cell density, and lower foam density. During the foaming process, intercalated clays were delaminated due to the rapid polymer melt expansion that inhibited gas release and increased foam expansion ratio. POLYM. COMPOS., 2011.