Processing and Characterization of Polypropylene Nanocomposite Films Reinforced with Hexagonal Boron Nitride Nanosheets

In this study, we synthesized hexagonal boron nitride nanosheets (h-BNN) via the molten hydroxide exfoliation method which results in small flakes and nanoscrolls. The resultant h-BNNs can be dispersed in various solvents such as water, ethanol, and acetone, and form a stable dispersion. The morphological and structural analysis of h-BNNs were performed with Fourier Transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), and scanning electron microscopy (SEM). The masterbatch (MB) method was used to incorporate the h-BNNs into the polypropylene (PP) matrix via melt mixing. Dilution and film production processes were performed using a twin screw extruder. Nanocomposite films having an h-BNN weight ratio of 1%, 2%, 3%, and 5% were prepared. Thermogravimetric analyzer (TGA) and differential scanning calorimetry (DSC) were used to investigate the thermal stability. Crystallization (Tc) temperatures were increased with the increased amount of h-BNNs and h-BNNs nucleating agent behavior on the PP crystallization was observed. Oxidation induction time (OIT) of the pure PP was increased from 8.84 min to 17.82 min. The results show a considerable effect of the h-BNN content on the thermo-oxidative stability of the nanocomposites studied. The rheological and mechanical properties of the PP-hBNN nanocomposite films were also determined depending on the particle loading ratio. Optimum particle content providing the best thermal, mechanical, and rheological properties were found to be 3% wt.