Location:Technology / PTFE properties  

Polytetrafluoroethylene(PTFE) is in greatdemand, making it representative of fluorocarbon polymers. The chemicalstructure of PTFE has the hydrogen atoms of polyethylene completely displacedby fluorine atoms to form a high molecule. Its chemical structure is as follow.

                           

 

The shield of fluorine atoms renders theC-C chain immune to chemical attack, and the extremely stable C-F bond isattacked only by highly aggressive agents, such as alkali metals or elementalfluorine.

 

The extremely good electrical properties ofPTFE arise from the rigid alternately arranged CF2 groups coupledwith minium electron mobility within the molecule.

 

The high degree of crystallinity in PTFEresults from the unbranched structure of the molecules.

 

PTFE exhibits marked anti-adhesiveproperties and has a low coefficient of friction, since outwards directedresidua valency activity is obstructed by the fluorine layers.

 

PTFE has a unique combination ofoutstanding properties, including high and low temperature resistance, chemicallinertness dielectric behavior, non-sticking and self-lubricating properties,and the lowest coefficient of friction of all solid materials. However, themechanical properties of PTFE are not necessarily superior to those of otherplastics. In particular, it suffers from its low resistance to wear and creep,and low hardness.

 

The greatest improvements realized byfillers to PTFE are in its mechanical properties. Most other properties andcharacteristics of the basic PTFE are remained. Practically any material thatcan withstand the sintering temperature of PTFE(360~380) can beused as a filler. Among the filler materials used are glass fiber, graphite, metallicoxides, carbon fiber, polymide, etc.