Teflon®
or polytetrafluoroethylene (PTFE) is similar to polyethylene in structure, but
there are many important difference between the two.
The C-F bonds in PTFE is responsible for its unique
properties. Fluorine is the most electronegative atom, thus a highly polar bond
results between flourine and carbon. The flourine atoms are held very close to the
carbon atoms and the electrons around the flourine atoms are held very tightly. In
effect, the flourine atoms act as a shield that prohibits other chemicals from reacting
with the chain of carbon atoms. This results in a very inert polymer. PTFE
will not burn or corrode. In fact when Teflon® is applied to cooking surfaces, it has to be bonded mechanically rather than
chemically. This is why the coating can be scraped off.
PTFE is very resistant to heat. At 327 0C, it becomes a thick,
non-flowing liquid. Above 327 0C, PTFE simply decomposes. PTFE
remains unchanged at temperatures as low as -269 0C!
Polymers have been modeled after PTFE to try to keep the positive characteristics of
Teflon®, but with signficant
advantages. The most notable of which would be a polymer that allows adhesion called
Perfluoroalkoxy (PFA).
