Constructing 3D interconnected CNTs network in PA6 composites with well-dispersed UHMWPE for excellent tribological and heat dissipation properties

Abstract

Recently, the requirements for wear resistance of materials under harsh pressure-velocity (PV) conditions become increasingly high. Herein, ultra-high molecular weight polyethylene (UHMWPE) via a novel efficient plasma treatment was introduced to disperse evenly in polyamide 6 (PA6) matrix and a three-dimensional (3D) interconnected carboxyl functionalized carbon nanotubes (CNTs) network was further constructed in PA6 composites via solvent-free ball milling and compression molding to achieve excellent tribological and heat dissipation properties. Friction tests show that the incorporation of the plasma-treated UHMWPE, as well as CNTs, leads to a significant reduction of the coefficient of friction (COF) of PA6 by 77.5%. Moreover, the 3D interconnected CNTs network forms a high-speed pathway for heat transfer and achieves a relatively high thermal conductivity (TC) of 0.40 W/(m K) at an ultra-low level of 0.2 wt% CNTs, which is 42.9% higher than that of pure PA6. Interestingly, the maximum contact temperature monitored by the infrared camera reduces greatly from 108.9 °C to 57.2 °C, indicating that low COF and high TC are beneficial for low contact temperature. As a result, the specific wear rate of PA6 composites is dramatically decreased by 98.1% compared to pure PA6. The strategy can be used to produce advanced bearing bushes and wearing laths in industrial applications.