PTFE has an unmatchable profile of unique properties which make it one of the most valuable and versatile engineering materials available.

Polytetrafluoroethylene - the high performance fluoropolymer

See below for more information on:

Total chemical resistance:

• Can be used in the most corrosive environments
• Will not contaminate the most sensitive medium

Completely insoluble with high purity

• No contamination in ultra-pure or corrosive applications
• Very high intrinsic purity

High thermal stability

• Working temperatures from -200 to +300°C
• Thermal degradation does not start until +400°C
• Does not melt to a liquid phase - an in-built safety feature

Exceptional electrical properties

• Extremely high electrical resistance
• Low dielectric constant and dielectric loss factor
• Does not support tracking

Exceptional anti-adhesion properties

• Lowest coefficient of friction of all solids
• Other materials exhibit little or no adhesion to PTFE

Good flexural properties

• Outstanding resistance to fatigue
• No embrittlement in liquid helium

Basic PTFE is a linear polymer of tetrafluoroethylene, CF2=CF2

Two co-polymers using perfluoropropylene-vinyl-ether (PPVE) as co-monomer are commercially important, these are:

• TFM, a copolymer with about 0.1% PPVE
• PFA, a copolymer with 3 - 15% PPVE

TFM is essentially similar to PTFE but with reduced porosity, improved tensile strength and a high degree of weldability.

PFA is a melt-processable thermoplastic with similar chemical resistance to PTFE. It has much lower porosity and is translucent.

FEP, Fluorinated Ethylene Propylene, a thermoplastic, is also a member of this family and shows the high chemical resistance characteristic of fluoropolymers along with excellent clarity.

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Properties of filled PTFE

A range of fillers, typically glass fibre, carbon, graphite, metal powders and molybdenum disulphide can be blended with PTFE resins, usually in the proportion of 2 - 40%, to improve certain characteristics.

The incorporation of fillers can:

• Increase compressive strength
• Improve thermal conductivity
• Improve abrasion resistance
• Reduce thermal expansion
• Reduce cold flow
• Impart electrical conductivity

It should be noted that the use of fillers may downgrade other properties of PTFE such as chemical and electrical resistance.

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Technical Data

Property	PTFE	TFM	PFA	FEP	Polypropylene
Appearance Density ( g.cm-3 ) Melting Point ( °C ) Max. Service Temperature ( °C ) Chemical Resistance Water absorption Hardness (Shore) Tensile Strength at 23°C (MPa) Elongation at break (%) Flammability Electrical Resistance (Ohms.m-1) Cost Index	Ivory-white, opaque 2.15 327 290 Excellent Nil 60 20-40 250-500 Non-flammable 1018 1.0	Ivory-white, opaque 2.15 327 290 Excellent Nil 60 40 250-500 Non-flammable 1018 1.5	Translucent 2.15 305 260 Excellent Nil 63-65 15-25 100-250 Non-flammable 1016 3.0	Transparent 2.14 270 205 Excellent Nil 63-65 20-30 250-300 Non-flammable 1018 2.5	Translucent 0.9 160 140 Short 110 Long Good except for HC and oxidising agents Nil 60-75 25-40 600 Ignites on flame contact & will burn 1016 0.25

Figures quoted are typical values

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