Original Article

Rheological, mechanical, and morphological behaviour of polypropylene composites reinforced with ultrafine kaolinite particles

¹ Département des sciences de la matière, Faculté des sciences et technologie, Université de Tamanghasset, 11000 Tamanghasset, Algeria
² Laboratoire de Physico-Chimie des Hauts Polymères (LPCHP), Département de Génie des Procédés, Faculté de Technologie, Université Ferhat Abbas, Sétif 19000, Algeria

^* Corresponding author: meziane.ouahiba@yahoo.com

Received: 6 December 2023
Accepted: 18 February 2024

Abstract

To develop charge/matrix interactions and improve the rheological, mechanical, and morphological performances of the matrix polypropylene, PP/kaolinite composites were prepared using the melt intercalation method at 190 °C. The rheological and mechanical properties of polypropylene/kaolin composites have been evaluated at various concentrations of untreated and/or treated kaolin. It was shown that the melt flow index (MFI) varies visibly but slightly compared to that of the matrix with increasing kaolin content. Furthermore, when the kaolin loading is enhanced, the apparent shear viscosity (η_app) of the composites increases compared to the matrix and decreases with the increase in the shear rate (γ_app). Also, while the shear stress (τ_app) is reduced, the flow curve shifts upwards with increasing the kaolin concentration. The systems obeyed the power-law model in shear stress-shear rate variations and were shear thinning as power-law index (n) values increased with kaolin content. Moreover, the mechanical properties of the obtained composites were significantly affected by the dispersion of the filler into the matrix and by the weak interactions at the interface PP/kaolinite. SEM micrographs show a poor dispersion of the nanoclay within the polypropylene matrix and the formation of agglomerates with different sizes.