Tribological Properties And Structure Of PSU,PES/PA6 In Situ Blends

Polymer blending is not only a means to tailor polymers, but also an important way to develop high performance materials. In situ polymerization is a fairly perfect method to manufacture polymer blends due to its simple realization and variety in many techniques. In this paper, Polysulfone(PSU)/Polyamide6(PA6) and Poly (ether sulfone)(PES)/Polyamide6(PA6) blends were obtained by in situ anionic polymerization. The crystal structure was studied by means of Wide Angle X-ray Diffraction(WAXD) and Differential Scanning calorimeter(DSC).The mechanical and tribological properties of the blends under dry friction condition and in water were also investigated. The main results are summarized as follows:1,WAXD studies indicated PA6 and its blends appeared inαform, but the interplaner spacing and crystallinity of the blends were different from that of pure PA6.Compared to PA6,the interplaner spacing of PSU/PA6 was enlarged and the crystallinity decreased, while PES/PA6 blends were opposite. DSC fusion curves also showed imperfect crystallization and decrease in melting point of both blends.2,The crystal structure of PA6 was perfected after being treated in oil in high temperature, whereas there was no obvious change for PSU/PA6 blends.3,Thermogravimetry(TG) studies presented improved thermostability for the blends. The wettability of the blends, evaluated by measuring contact angle of water on the surface, was also decreased. The tensile strength and tensile modulus were increased simultaneously, but the toughness was decreased. There was no obvious change in hardness for PA6 and its blends.4,The coefficient of friction of PA6 and its blends was almost equal under dry condition, but the blends demonstrated superior wear resistance than pure PA6. The main wear mechanism of PA6 was adhesion wear, while that of PSU/PA6 blends was abrasion wear. On the condition of high load and high speed, PA6 was more wear resistant than the blends, to which the imperfection of crystal of the blends contributed. And the main wear mechanisms of PA6 were adhesion wear and fatigue wear, while that of PSU/PA6 blend were abrasion wear and fatigue wear.5,The tribological properties were also tested under water lubricating. Plasticization by water caused increase in wear and decreased coefficient of friction. The dominant wear mechanism of PA6 was adhesion wear while that of PSU/PA6 blend was abrasion wear.