Enhancement of Thermal, Mechanical, and Oxidative Properties of Polypropylene Composites with Exfoliated Hexagonal Boron Nitride Nanosheets
Amit Kumar Sonker, Man Hieu Tran, Nathan Park, Gouri Sankar Das, Hansa Mahajan, Tae Hee Lee, Tae Young Kim
Abstract
This study investigates the enhancement of polypropylene (PP) composites through the incorporation of exfoliated hexagonal boron nitride (h-BN) nanosheets. The preparation process involved exfoliating h-BN in a liquid phase using a high-pressure homogenizer, followed by the coating of PP pellets with the exfoliated nanosheets using an acoustic mixer. Melt extrusion was then employed to fabricate h-BN-reinforced PP composite films. Characterization techniques, including scanning electron microscopy, confirmed the uniform dispersion of exfoliated h-BN within the PP matrix, which is crucial for improving thermal conductivity, mechanical strength, and oxidative stability. Tensile testing demonstrated that exfoliated h-BN significantly enhanced the strength and toughness of homopolymer PP, while the improvements in impact copolymer PP were more modest. Thermal analysis revealed no significant change in the decomposition temperatures of PP but indicated improved oxidative stability with the incorporation of h-BN nanosheets. Notably, the oxidation resistance of PP was enhanced, as evidenced by reduced carbonyl index values in thermally aged samples. Overall, exfoliated h-BN nanosheets significantly improve the performance of PP composites, demonstrating their potential for diverse industrial applications that require superior thermal and mechanical properties, as well as enhanced oxidation resistance.