A drill bit (100) for drilling a wellbore that traverses subterranean
formations includes a drill bit body (106) having a plurality of journal
pins (112), each having a bearing surface (128), and a rotary cutter
(104) rotatably mounted on each journal pin (112), each rotary cutter
(104) including a bearing surface (126). A pressure-compensated reservoir
(130) is in fluid communication with the bearing surfaces (126, 128) and
has a lubricant therein. A seal element (144) is positioned between each
journal pin (112) and rotary cutter (104) and retains the lubricant in
the bearing surfaces (126, 128). The seal element (144) is formed from a
nanocomposite material including a polymer host material and a plurality
of nanostructures.