Compounds (Basis PTFE/modified PTFE)

Fillers are incorporated into PTFE for the following reasons:
  • Wear resistance is increased significantly
  • Cold flow under load is significantly reduced
  • Depending on the type of filler used, thermal conductivity may increase by a multiple
  • Thermal expansion is reduced
  • If required, the electric properties of the PTFE matrix may be modified by the selection of appropriate fillers
  • In addition, the choice of filler influences wear behavior of the mating surface
The influences on the ultimate properties of the compound, which may be influenced by both the PTFE matrix and the filler, have been summarized in the following table:

Influencing
parameter		 Mechanical
property		 Cold flow Friction
coefficient		 Wear Chemical
resistance		 Expansion
coefficient		 Thermal
conductivity
Effects when exchanging PTFE for mod. PTFE
Influence of fillers on the product properties of compounds

Trends:
lightgreenPositive
blauNeutral
orangeNegative

The direction of the arrows indicates the decrease or increase of the parameter. The color of the arrows describes the influences on the ultimate properties of the compound.

PTFE-Type Influence of Fillers Filler Content in % of Weight Limits of Use
PTFE filled with glass fibers
  • higher pressure and wear resistance as well as better thermal conductivity
  • very good chemical resistance
  • good dielectric properties
up to 40% resistant to organic solvents, non-resistant to alkaline solutions and acids
PTFE filled with carbon fibers
  • very low deformation under load
  • good wear resistance, even in water
  • higher thermal conductivity and lower thermal expansion than glass fibers
  • very good chemical resistance
 up to 25% carbon fibers are chemically inert
PTFE filled with carbon
  • high pressure resistance and hardness
  • good sliding properties and wear behavior
  • good thermal conductivity
  • good chemical resistance
  • low volume and surface resistivity
  • electrically conductive
 up to 35%, also in combination with graphite compound is brittle, filler may be attacked by oxidizing media
PTFE filled with graphite
  • good lubricating effect
  • low friction coefficient
  • no static charging
  • good thermal conductivity
  • very good chemical resistance
 typically up to 5%, in exceptional cases up to 15%, also in combination with glass fibers or carbon high abrasion when used with hard metals, is attacked by oxidizing media
PTFE filled with molybdenum disulfite (MoS2)
  • good sliding properties and wear behavior
  • good no-lube operation in combination with bronze
 up to 10%, also in combination with glass fibers or bronze not resistant when used with hot, concentrated sulfuric acid
PTFE filled with bronze
  • good sliding properties and wear behavior
  • low cold flow
  • good thermal conductivity
  • lower chemical resistance
  • high pressure resistance
 up to 60%, also in combination with MoS2 may be attacked by acids and water
PTFE filled with organic fillers (high-performance thermoplastics)
  • outstanding sliding properties and wear behavior
  • good chemical resistance
  • high pressure resistance in some cases
  • suitable for soft mating surfaces, e.g. aluminum
  • non-abrasive
 up to 20%, may be higher in combination with different fillers depending on the respective filler