Improved thermal conductivity, mechanical, and flammability properties of polypropylene/hexagonal boron nitride/silicon carbide nanocomposites using a titanate-based coupling agent

An increasing demand persists for advanced materials such as polymer nanocomposites with improved thermal and mechanical properties while preserving their electrical insulation. Accordingly, hexagonal boron nitride (hBN) and silicon carbide (SiC) reinforced polypropylene (PP) nanocomposites were prepared both with and without the use of a titanate (Ti)-based coupling agent. The influence of the filler content and the use of a compatibilizing agent on the final properties were investigated. PP/hBN/SiC and PP/Ti-hBN/Ti-SiC hybrid polymer nanocomposites reinforced at various filler contents (20 wt.%, 40 wt.%, and 50 wt.%) were produced using mechanical mixing and compression molding methods. As the filler content increased, the elastic modulus of PP improved by 57%, and mechanical strength was notably enhanced. The use of Ti was found to promote a more homogeneous distribution of the fillers, improving flexibility and impact resistance. Thermal analyses showed that the fillers improved the thermal properties of PP, while excessively high filler contents could lead to adverse effects. The thermal conductivity increased by 216% for the 20 wt.% hBN/SiC-filled samples compared to pure PP, and this increase reached 248% for the titanate-treated samples. These results highlight the potential of PP-based nanocomposites for industrial applications and emphasize the need for optimization.