The surface of nano-La2O3 was modified. Effects of various amount of treated nano-La2O3 on the mechanical and tribological properties of PTFE were investigated. Mechanisms that contribute to the properties of PTFE composites are also studied. Results indicate that treated nano-La2O3 can increase the mechanical and tribological properties of PTFE simultaneously. With 1wt.% of treated nano-La2O3, the rigidity, tensile strength, notched impact and wear resistance of PTFE nanocomposites were increased by 25.1%, 14.1%, 20.3% and 36.7% respectively over pure PTFE. The degradation temperature of PTFE was improved by 14 ℃ by adding only 5% nano-La2O3. The wear resistance reached the highest value when the composite contained 10% treated nano-La2O3, which is about 110 times higher than pure PTFE. Furthermore, treated nano-La2O3 strengthened the bonding between the transfer film and the counterpart surface. A coherent and smooth transfer film on the counterpart surface of PTFE composites can be observed, while pure PTFE can not do.
