The Tribology and Micromechanics of Polystyrene-Montmorillonite Nanocomposites

The mechanical and frictional properties of polymer nanocomposites based on a polystyrene matrix and montmorillonite were studied by using the microindentation technique and an atomic force microscope in the frictional microscopy mode. The micromechanical tests revealed a decrease in the modulus and microhardness of the composite compared with those of a neat polystyrene, with a minimum of their values at 1-3 wt.% of the filler. However, a local maximum of the tensile modulus of the filled polymer arose and increased at the same filler concentration. The frictional microscopy pointed to an anisotropy of the friction coefficient of the nanocomposite and to its noticeable dependence on the content of the filler. The maximum value of the friction coefficient was also reached at 1-3 wt.% of the filler.