On the scratch deformation of micrometric wollastonite reinforced polypropylene composites

Scratch deformation characteristics of neat and wollastonite-containing polypropylenes under identical test conditions are examined by electron microscopy and atomic force microscopy techniques. The study indicates that the severity of plastic deformation during scratch deformation in filled polypropylenes is a strong function of the debonding/detachment of wollastonite mineral particles from the polypropylene matrix. Scratch resistance is evaluated in terms of scratch hardness, scratch depth, average scratch roughness, thickness and density of the scratch tracks. Atomic force microscopy suggests the presence of a localized region surrounding the reinforcement particle that is characterized by enhanced crystal nucleation in which the local chain conformation and kinetics are likely to be different from regions that are a significant distance away from the mineral particle.