Tribology of self-lubricating polymer nanocomposites

In the last few years, polymeric materials filled with different kinds of nanomaterials have attracted particular attention as useful alternatives in structural components subjected to severe friction and wear loading conditions. The intention of this chapter is to give a comprehensive picture of these nanofillers and to show their ability to improve friction and wear behavior of polymer composites. The aim is to organize the current state-of-the-art knowledge on these nanomaterials and point out on the key mechanisms governing their reinforcing effects. Despite the existing differences between literature results, there is a general agreement on the crucial role played by size, shape, concentration, and distribution of these fillers within the polymer matrix. The compatibility/interaction between filler and matrix is another important aspect in determining good filler dispersion and effective load transfer between the phases. As a consequence, the development of polymer nanocomposites showing high tribological features requires a deep selection of the nanofiller type and dimension along with its possible surface modification. Fortunately, modern technologies allow the design and the preparation of complex hybrid nanostructures able to put together the benefit of several structural factors. Although the state of the art demonstrates the potential of these materials, further researches are, however, necessary in order to definitely reach all possible improvements attainable for future high-demanding tribological applications.