Structuration of organoclay/polypropylene nanocomposites during twin screw extrusion process

Guillaume Normand (1) , Edith Peuvrel-Disdier (1) , Bruno Vergnes (1)

1 CEMEF - Centre de Mise en Forme des Matériaux

Summary : Reaching nanoscale dispersion of the layered silicate within polypropylene (PP) matrix is challenging and requires both the use of a compatibilizer and optimal processing method. We showed in a previous work that the specific mechanical energy received during extrusion was the key parameter controlling this microstructure with a saturation of the dispersion state above a certain level of energy [1-2]. The present study aims at better understanding the effect of the specific mechanical energy on the dispersion process. Nanocomposites of polypropylene, maleated polypropylene and organomodified montmorillonite were prepared in a co-rotating twin-screw extruder by direct mixing. The effect of the specific mechanical energy was investigated by varying extrusion parameters such as the screw speed, the barrel temperature and changing the matrix viscosity level. A particular attention was paid to high screw speed conditions. Dead stop experiments were conducted and the nanocomposite structure was followed along the screw profile. The structure was systematically quantified via scanning and transmission electron microscopy, X-ray diffraction and dynamic rheometry in to order to analyse the structure at different scales. A clear relationship is once again shown between the specific mechanical energy given to the system and the organoclay dispersion state with a saturation above a certain screw speed. This saturation was shown to be related to the thermo-mechanical degradation of polymer chains. The effect of the polymer chain degradation on dispersion will be discussed. References: [1] T. Domenech, E. Peuvrel-Disdier, B. Vergnes. Int. Polym. Proc. 2012, 5, 517-526. [2] T. Domenech, E. Peuvrel-Disdier, B. Vergnes. Compos. Sci. Technol. 2013, 75, 7-14. Acknowledgements: The research leading to these results has received funding from the Seventh Framework Programme of the European Union (FP7 / 2007-2013) under grant agreement n ° 314744.

Mots clés: Polymer melts; blends; composites and solid polymers

Domaines: Matériaux

Guillaume Normand, Edith Peuvrel-Disdier, Bruno Vergnes. Structuration of organoclay/polypropylene nanocomposites during twin screw extrusion process. 10th Annual European Rheology Conference (AERC 2015), Apr 2015, Nantes, France. 1p. ⟨hal-01502217⟩