Effect of graphite and Ag-plated graphite nanoplatelets on the thermal properties of polypropylene nanocomposites: Experimental studies and modeling

The effects of using graphite nanoplatelets (GNPs) and Ag-plated GNPs (Ag-GNPs), as fillers on the thermal properties of nanocomposites based on polypropylene (PP) matrix are investigated in this study. GNPs were exfoliated from expanded graphite after oxide-intercalation and ultrasonic methods. The Ag-GNP was fabricated by electroless plating. The morphologies of the fillers were characterized, and the thermal properties of the obtained nanocomposites were evaluated. Results indicated that the incorporation of the two fillers improved the thermal stability, and the 5% weight loss temperature had increased to 67.82 °C. Thermomechanical analysis showed that the softening temperature increased by 5-8 °C relative to that of PP. The thermal conductivity of the nanocomposites that contained 20 wt% GNP (11 vol%) significantly improved from 0.18 W/(m K) to 1.05 W/(m K). Comparison of the experimental data of the nanocomposites with four theoretical models showed that the data of GNP/PP nanocomposites and Ag-GNP/PP nanocomposites matched well with the Nielsen-Lewis model and the Russell model, respectively, except for certain deviations.