Wang Honggang

Effect of Compatibilization on Reciprocating Frictional Behavior of Polyamide 66/UHMWPE Blends

ABSTRACT The effect of compatibilization on the reciprocating frictional behavior of a polyamide 66 (PA66)/ultra-high molecular weight polyethylene (UHMWPE) blend was investigated. The influence of the amount of added maleic anhydride–grafted polyethylene (MAH-g-HDPE) on the phase morphology, compatibility, and viscoelasticity was explored using scanning electric microscopy (SEM), dynamic mechanical analysis (DMA), and capillary rheometry. In addition, the effect of MAH-g-HDPE on the reciprocating friction and wear performance of the PA66/UHMWPE blend was tested. The worn surface, transfer film, and wear debris were analyzed using SEM, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). The results showed that the maleic anhydride groups in the MAH-g-HDPE improved the compatibility of PA66 and UHMWPE, and the addition of MAH-g-HDPE enhanced the interface bonding strength and lowered the polar difference between PA and UHMWPE. Therefore, the improved compatibility enhanced the wear resistance of the blend. During reciprocating sliding, UHMWPE transferred to the counterface prior to PA66 for the incompatible blend. The addition of MAH-g-HDPE promoted the adhesion and transfer of PA66 to the counterface.

Tribological Behavior of PTFE Composites Filled with PEEK and Nano-Al2O3

ABSTRACT In this study, the tribological properties of polytetrafluoroethylene (PTFE) composites filled with polyetheretherketone (PEEK) and nano-Al2O3 particles were studied using a block-on-ring wear tester. The tribological performance of the composites was affected by the experimental parameters (sliding speed, normal load, and environmental temperature) and the composites achieved a high-speed sliding friction state. The results showed that the PEEK and nano-Al2O3 particles significantly improved the wear resistance of the PTFE composites. In addition, the nano-Al2O3 particles increased the hardness of the composites and enhanced the mechanical properties to enable applications in a wider range of industrial fields. The effects of the sliding speed and normal load on the tribological properties were more significant than that of the environmental temperature. In addition, the entire wear process was divided into three stages (the initial wear stage, severe wear transition stage, and ultralow stable wear stage), according to the evolution of the tribological characteristics (wear rate, morphology of the worn surface and transfer film, and wear debris morphology).