5. Conclusion

In this article, attention was focused on the preparation of nanocomposites based on PP and lamellar clay by melt mixing in a twin-screw extruder. The microstructure of the nanocomposites was mainly determined by measuring the area ratio (characterizing the number and size of large agglomerates) by scanning electron microscopy and the apparent flow threshold (characterizing the level of exfoliation) by low-amplitude oscillatory rheometry. The influence of the main operating parameters (screw speed, feed rate, sheath temperature) on the level of dispersion at the different scales was highlighted. It was shown to be directly linked to specific mechanical energy (SME), but also partially controlled by the thermal history supported by the nanocomposite. By coupling a bivariate extrusion flow model and evolution laws for area ratio and flow threshold, it is possible to model microstructure changes...