Mechanical and tribological properties of PA/PPS blends

Polymer blending is a very important and widely used method for the modification of polymer materials. The mechanical properties, miscibility and modification mechanisms of blends have been investigated earlier. However, studies of their tribological behavior have been few, and little attention has been paid to the friction and wear mechanisms of polymer blends. In this paper, the structure, mechanical and tribological properties of polyamide 66 (PA66) and polyphenylene sulfide (PPS) blends were studied. It was found that the PA66/PPS blends had a two-phase structure; the blend with 30 vol.% PPS exhibited the best general mechanical properties; 80 vol.% PA66–20 vol.% PPS blend had the lowest wear. Differential scanning calorimetry (DSC) and Fourier transform infrared spectrometry (FT-IR) analyses were carried out and the transfer films on the mating steel surfaces were investigated by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The results indicated that the crystalline structure of PA66, PPS and PA66/PPS blends changed due to sliding and tribochemical reactions occurred with the PA66 and the PA66 phases in blends. The thermal control of friction model is applicable to this blend system, i.e. the friction coefficient of PA66/PPS blends depended on the PA66 component with lower melting point, while the wear properties were governed by the adhesive ability between the PPS and the counterface.