[AMPS] Alert-- ptfe does NOT give phosgene

[Dave Bowker]

Teflon is a (fluorocarbon resin) or (flourine plastic) and has the same
structure as polyethylene, in which the hydrogen is replaced by (flourine).
OR  a part may be replaced by (chlorine), in which case it is called a
(fluorohalocarbon resin).

Polymerized (tetrafluoro ethylene), aka PTFE, which carries the E.I. du Pont
trade name of  Teflon,  formula (CF2*CF2)n  is probably the most common
solid form used for insulating materials, bearings, gaskets, insulating
tapes, wire insulation, etc.  This is a white waxy solid with specific
gravity of up to 2.3, typical tensil strengths of up to 3500 psi, elongation
of 250-350%, dielectric strength of 1000 v/mil and melting point of 594*F.

Another commonly encountered material in electronic use and sometimes
referred to generally as "Teflon", is Teflon FEP, which is a fluorinated
(ethylene-propylene).  In thin films (typically down to 0.0005"), it is most
frequently found as insulation in capacitors.  Typical tensil strength is
3000 psi, elongation 250%,  and dielectric strength 3200 V/mil.

Neither PTFE or Teflon FEP emit phosgene upon decompositon at elevated
temps.

However, fluorothene plastic (which may be what Rich's info was referenced
to) has the formula (CF2*CFCL)n  and differ from (Teflon) in having one
chlorine atom on every unit of the polymer chain, replacing  the 4th
fluorine atom.  This is a (transparent) material with a specific gravity of
~2.1, has tensil strengths of up to 9400 psi, but has a lower withstanding
temp (as related to Teflon) of around 300*F.  This material is sometimes
called "Teflon" due to its similarity in chemical and polymer-structure
make-up, and will emit phosgene upon decomposition at elevated temps.

73, Dave, K1FK
Fort Kent, ME


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