Morphological stability of poly(propylene) nanocomposites

Poly(propylene) compounds containing organophilic layered nanosilicates wer e prepared by means of melt extrusion at 210 degreesC in order to investiga te the influence of maleic anhydride-grafted poly(propylene) (PP-g-MA) as a compatibilizer on morphology development and rheological properties. It wa s found that the addition of PP-g-MA leads to the strong exfoliation of sil icate layers within the matrix as investigated by WAXS. This process is ass ociated with the build up of an unstable morphology as probed by dynamic rh eology and with the violation of the time-temperature superposition princip le. Annealing of the samples at extrusion temperature level leads to a coar sening of the silicate superstructure and further improvement of the exfoli ation at the same time. This process results in a stable morphology with un ique rheological properties indicating network-like superstructure of silic ate layers.