PTFE
(Polytetrafluoroethylene )

General information
  Name    :   Polytetrafluoroethylene (PTFE )

  Chemical Formula :    --[- CF2 – CF2 -]-- n        

  Formula weight   0.5-1.0 million

Physical & Chemical Characteristics
  PTFE has good heat-resistance , can be used for a long time under 260 °C high temperature , or temporarily under – 268 °C . It will decompose slowly and give out toxic gas when heated to 415 °C . It can bear any other chemicals except melting sodium and gaseous fluoride and do not change even in boiling chloronitric acid., especially its comprehensive property : excellent self–lubricating property , wide adoption for distant temperature range , perfect chemical stability ,anti-dirt , anti-coagulation , anti-aging , therefore , it is praised by people as “ The king of plastic resin “
Applications
PTFE is widely used in space flight , atomic energy , electronics , machinery , chemical , textile , building , instrument , computer , medical , equipment , light industry , including skived film and sheet , gaskets , packing, mechanical seals , bridge or pipeline bearing pads, shaft bearings, electrical insulators , piston rings , expansion bellows , diaphragms ,and chemical linings .
Physical Property

No

Item

 

Unit

Data sheet

Note

1

Relative density

 

2.1 – 2.3

 

2

Melting point

°C

327  +/-  5

 

3

Moisture

%

0.04  Max

 

4

Hardness

D

50 – 65

Rockwell hardness

5

Highest temperature allowed using .

°C

260

 

6

Coefficient of static  friction

 

0.04

Between brakes

7

Yield tensile strength

 

MPa

7.252/2.744

250 °C / 100°C

8

Modulus of elasticity in static bending

Mpa

350 – 630

28 °C

9

Coefficient of thermal expansion

10 –-5 / °C

5 – 10

 

10

Dielectric constant

 

 

2.1

 


Storage and Handling
  Performing is easiest when the resin is uniformly between 21-27 C ( 70-80 F ) . As temperature declines below this range , the resin will be increasingly difficult to mold without cracks and problems with condensed moisture . High temperatures inhibit flow and promote lumping . Storage condition should be set accordingly .

   Cleanliness is a critical requirement for successful use of PTFE . The white resin and high sintering temperatures cause even very small foreign particles to become visiblein finished moldings. Keep resin drums closed and clean . Good housekeeping and careful handling are essential .



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