Comparison of the reinforcing effect of various micro- and nanofillers in PA6

Composites were prepared from three traditional microfillers, glass beads (GB), wood flour (WF) and glass fibers (GF), as well as sodium montmorillonite (NaMMT) and an organophilic clay (OMMT) in a polyamide (PA) matrix in order to compare their properties and discuss the benefits and drawbacks of using micro- or nanofillers. Structure was characterized by various techniques, interaction estimated by two approaches and local deformation processes were followed by acoustic emission testing and volume strain measurements. The results showed that properties can be modified in a relatively wide range. True reinforcement can be achieved with glass fibers, but the influence of all traditional fillers can be predicted with good certainty because their structure can be controlled quite well. Although the layered silicates reinforce polyamide even better than glass fiber, improvement is achieved only in a very narrow composition range because the structure of their composites cannot be controlled to the desired extent. Numerous local processes take place during the deformation of PA composites, such as cavitation and shear yielding in the matrix, as well as particle related processes. However, it is matrix deformation rather than particle processes that determines composite properties.