The ePTFE that I mentioned earlier is the Gore development. Regular PTFE
was around much longer.
I got the whole history lesson some years ago from a good friend who was the
regional manager of the Gore CTE Division; they printed a nice glossy
pamphlet showing the history and development.
My wife and I still have Gore-Tex winter jackets we received from him as
Christmas presents, impossible to wear out!
Carl
KM1H
----- Original Message -----
From: "Jim Jarvis" <jimjarvis@optonline.net>
To: <gdaught6@stanford.edu>; <towertalk@contesting.com>
Sent: Saturday, July 28, 2007 9:25 AM
Subject: [TowerTalk] Teflon vs. PTFE
>
> w1jr wrote:
>
> < snip >
>
>> In 1989 I helped develop a low cost PTFE coax for the Cushcraft
>> Corporation. They needed a cost effective coax for installing mobile
>> antennas in automobiles that wouldn't melt if placed near catalytic
>> converters etc. Cushcraft marketed it as "Ultra Link" coax. Ultra
>> Link, as I recall, is about the diameter of RG58. It uses PTFE
>> (instead of teflon) dielectric.
>
> k6gt questioned: Hmmm. I was under the impression that "Teflon" IS
> "PTFE".
> I thought
> that Teflon was DuPont's trade name for PolyTetraFluoroEthylene.
> <snip>
>
> quoth wikipedia:
>
> Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer which finds
> numerous applications. PTFE's most well known trademark in the industry is
> the DuPont brand name Teflon, as DuPont initially discovered PTFE.
> <snip> <summary appendage> Roy Plunkett is credited with the serendipitous
> discovery in 1938.
>
> To which I add:
>
> Gore later worked with extruding and drawing the stuff, to discover that
> its
> physical and dielectric properties changed with stress. Micro pores
> were created by the process. Which is why Goretex fabric foul wx gear
> breathes.
>
> In high-precision measurement systems, distinction was made between teflon
> and PTFE, as to differences in dielectric properties. If you're measuring
> charge..and using teflon cables...it could take several minutes to
> discharge
> the teflon cable capacitance to allow a proper measurement....whereas PTFE
> has a lower dielectric constant, due to the micropores. i.e. Same stuff,
> slightly different form.
>
> N2EA
>
>
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