Unit 3- Class 13- High Polymers (Some commercial polymers - Teflon)

TEFLON (PTFE- polytetrafluoro ethylene):

Teflon is the trade name for PTFE. The monomer TFE is obtained by the following reaction.

                  CHCl3 + 2HF----------->CHClF2 + 2HCl     
                Chloroform                      Chlorodifluoro methane

               2CHClF2--------------->CF2=CF2 + 2HCl    
                                     TFE

Teflon is usually manufactured by emulsion polymerization of TFE using peroxide as initiators.
                              peroxide
          n CF2=CF2---------------->(-CF2 – CF2 -)n
        Teflon

Properties: 1. High degree of crystallinity 2. High m.p 3. High density 4. Insoluble in any solvent 5. High resistance to corrosive chemicals, oxidizing and reducing agents.6. Not wetted by either oil or water.7. Remains slippery over a wide range of temperature (-40 to 3000c). High thermal stability, good mechanical strength 9. Excellent electrical insulating properties.

Applications: 1. It is used for insulation of motors, generator, transformers, coils, capacitors, wires and cables.
2. Teflon is coated on articles such as bakery trays, frying pans and food processing equipments. 
3.Gaskets, industrial filters, widely used in army weapons.
4.Teflon is an ideal lubricant therefore used for non- lubricated bearings and as a dry lubricant.