(350n) Deformation and Wear in Nanocomposites

Fundamental atomistic and molecular processes have been applied to tribological contacts. Wear mechanism can occur from abrasion, adhesion and by fatigue.. Nanocomposites depict elastic or elastic plastic behavior and particle to particle interactions depending on the extent of deformation and dispersion of particles in the matrix. However, these interactions are balanced in each nanocomposite systems by the surface treatments (chain grafting, filler modification) and the molecular weight of the matrix. Nano-indentation of polymer films undergoes strain softening and strain hardening depending on the stiffness of the surface at different depths. Our results on polycarbonate and on polyester containing nanoparticles of silica showed that there is an increase in modulus and hardness up to a certain concentration in threshold of concentration. As the level of nanoparticles increases beyond a threshold level, aggregates form which results in weakening of the structure. Polymer nanoparticles interface is found to be weak as filler is non-interacting promoting interfacial slip at the filler- matrix junctions. At critical stress level for silica –polymer interfacial slip is reached and filler-matrix sliding is activated resulting in a decrease in the composite’s stiffness. Wear and friction are computed considering the effect of the interface between the hard filler and relatively soft polymers.