Effect of simple shear induced orientation process on the morphology and properties of polyolefin/graphite nanoplates composites

In this work the advantages of the reinforcement effect induced by solid state simple shear were demonstrated on the example of polyolefin/graphite nanoplates (GnP) composites. It was shown that the simple shear promotes significant changes in the crystal structure and the morphology of the GnP and the polymer matrix: extensive exfoliation of the GnP agglomerates into the layers consisting of several graphite plates, GnP crystal and crystal lamellae orientation. The oriented nanocomposites were characterized by a reduced porosity and improved adhesion between the GnP and the polymer matrix. An increase in Young modulus, yield stress and strain at break was observed, being accompanied by a substantial decrease in the thermal expansion coefficient of the GnPs-based nanocomposites. The effects depend on the type of the polymer, concentration and morphological characteristics of GnP.