Rheology of nanocomposites based on layered silicates and polyamide-12

Nanocomposites based on polyamide-12 (PA-12) and layered silicates are synt hesized and analyzed with respect to their morphological and rheological pr operties. Transmission electron microscopy shows the fine dispersion of sil icate layers in a PA-12 matrix. Different swelling agents for the clay (pro tonated aminododecanoic acid or water) are used. This allows the molar mass of PA-12 to be controlled during the preparation of the nanocomposites. Wh en aminododecanoic acid is used as a swelling agent, the exfoliated silicat e layers are chemically bonded to the matrix, whereas the use of water as a swelling agent leads to exfoliated silicate layers well dispersed in the p olymer matrix without tethered polymer chains. The rheological behavior of the nanocomposites differs extremely from that of the pure PA-12 matrices. A qualitative description of the rheology of these nanocomposites is provid ed.