Chemically Functionalized Graphene–Boron Nitride/Polypropylene Nanocomposites with Enhanced Nanomechanical and Anti-wear Properties

Abstract

Polymers are soft materials with large molecular chains, which are softened during frictional wear, leading to bulk detachment of materials and poor wear resistance in addition to their low mechanical strength and hardness. This study developed polypropylene nanocomposites containing hydrothermal assembled graphene and boron nitride (BN@GNs) with good mechanical properties and wear resistance. To ensure good dispersion of the nanoparticles in the polypropylene (PP) matrix, they were functionalized and preparation of masterbatch using polypropylene maleic anhydride (PPMA) was adopted, while the polymer nanocomposites for this study were developed via melt compounding. The addition of the nanoparticles in the PP matrix promoted its wear resistance as all the developed nanocomposites showed a low coefficient of friction (CoF). The wear rate of the nanocomposites was dramatically reduced to a minimum of 2.05 × 10−4 mm3/Nm for the PP/3wt%BN@GNs nanocomposite from around 24.9 × 10−4 mm3/Nm for the pure PP. The nanoindentation test results of the nanocomposites also revealed improvement in their nanomechanical characteristics. For instance, PP/3wt%BN@GNs nanocomposite showed an ideal increase of about 124% nano-hardness and 65.7% nano-elastic modulus when compared to pure PP. In comparison to pure PP, all of the developed nanocomposites displayed lower nano-percentage creep and nanoindenter’s tip penetration depth, which suggest greater plastic deformation resistance.