4. Lubricated compounds

These are thermoplastics to which often significant quantities of internal lubricants such as PTFE, silicone oil, graphite, molybdenum disulfide (MoS ₂ ), etc. are incorporated. As they are expensive, they are used in mechanical fields such as gears, cams, guides, bearings. Their low density reduces the inertia of moving parts, dampens parasitic noise, and eliminates or reduces the need for oil or grease. Finally, their ease of processing allows total freedom of design.