Para-phenylene terephthalamide (PPTA) pulp reinforced nitrile-butadiene rubber (NBR) composites were prepared on mill mixer.The effects of fiber content

friction time and load on the friction and wear properties of the composites under dry condition and water lubrication were investigated and wear mechanisms were discussed.The mechanical and tribological properties of the composites were significantly improved by the incorporation of PPTA-pulp.When the proportion of fiber was 20%(mass)

the composite showed the best performance.Under dry condition

the friction coefficient of the composites decreased and abrasion loss increased with the extension of friction time

and they both increased with increasing load.Compared with dry friction

the friction coefficient and abrasion loss of the composites decreased greatly under water lubrication.Besides

they were more stable owing to the lubricating and cooling effects of water.The main wear mechanism of the composites was abrasive wear and fatigue wear under dry friction while the wear mechanism was slight abrasion under water lubrication.