An investigation of friction and wear behaviors of polyimide/attapulgite hybrid materials

PI/AT hybrid materials were prepared by blending of poly(amic acid) and purified AT as a type of fibrillar clays. The friction and wear behaviors of the PI hybrids were evaluated on a ball-on-disc wear tester. The particle size of AT in the hybrid containing 5 wt.-% AT was about 10-1.00 nm in diameter and 100-1000 nm in length. Tensile tests on the PI hybrids showed that the strength and the toughness of PI/AT hybrid materials were improved simultaneously when the content of AT was less than 5 wt.-%. The friction coefficient and wear rate of the PI hybrids first decreased and then increased with increasing content of AT. The wear rate of the hybrid containing 3 wt.-% AT was more than 6 times lower than that of pure PI. SEM examination of worn surfaces showed that type of wear changed from adhesive wear of pure PI into abrasive wear of the PI hybrids with adding AT to PI matrix. Debris analysis suggested that AT as filler inside the PI matrix could prevent the formation of bigger debris and a chemical reaction that occurred during the friction process of pure PI but not in the hybrids.