Achieving enhanced interfacial adhesion and highly oriented structure in PA6/Graphite composites for excellent tribological performance

Abstract

Friction and wear properties of polyamide (PA) materials can be improved by graphite (Gr) due to its superlubricity. For further enhancing the ultimate properties of composites, the interfacial adhesion between Gr and PA has already attracted growing attention, while the contribution of Gr arrangement is often ignored. In this work, the interfacial adhesion was improved by π-π interactions between Gr and 1,3-Bis(4,5-dihydro-2-oxazolyl)benzene (BOB) functionalized PA6 via reactive extrusion. Moreover, the highly oriented structure of Gr was achieved by the strong extensional and shearing field. Experimental results indicated that BOB functionalized PA6 with 20 wt% highly oriented Gr (PA6-BOB/HOGr20) displayed excellent balanced performance. Compared with pure PA6, the coefficient of friction (COF) and specific wear rate of the PA6-BOB/HOGr20 composite were reduced by nearly 42% and 46%, respectively. Furthermore, its in-plane thermal conductivity (TC) reached as high as 2.14 W/(m K). Due to the low COF and high TC, the tribo-surface temperature was consistently lower than its glass transition temperature (Tg) under harsh pressure-velocity (PV) conditions of this experiment. In addition, the PA6-BOB/HOGr20 composite still has high ductility, and the elongation at break reaches 150%. This work provides a facile and environmentally friendly method for designing high-performance wear-resistant composites, which can be used as linear guide rail, liner, and linear bearing in industrial applications.