Mechanical, thermal, and rheological properties of polypropylene hybrid composites based clay and graphite

Polypropylene hybrid composites based on a mixture of graphite and clay were compounded by twin-screw extrusion and injection molded. In particular, the effect of reinforcement content and ratio of each particle was studied via morphological, mechanical, rheological, and thermal properties. The properties were evaluated in both solid and melt state to determine the mechanical performance of these materials. The results showed that these composites have excellent mechanical properties when compared to the neat polymer matrix. For example, the tensile moduli are 1607 and 1445 MPa for 30 wt% of clay and graphite respectively, while a 10:10 ratio of clay/graphite produced a value of 1500 MPa. Morphological analyses showed good adhesion/dispersion of both particles in the matrix, which was confirmed by good tensile strength results. Also, thermal stability was improved by adding clay and graphite particles, the results showing between 40 degrees C and 50 degrees C increased at 20 wt% content. Finally, a combination of graphite and clay is shown to produce hybrid composites with improved performances.