From: John Woodgate
Subject: Re: Best insulator?
Date: Sat, 7 Sep 2002 19:43:00 +0100
Organization: JMWA Electronics Consultancy
Reply-To: John Woodgate
NNTP-Posting-Date: Sat, 7 Sep 2002 20:38:19 +0000 (UTC)
X-Newsreader: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>
I read in sci.electronics.design that Duane C. Johnson
wrote (in <3D7A27D9.F33C0959@redrok.com>) about
'Best insulator?', on Sat, 7 Sep 2002:
>> I think 'Mylar' is the name for polyethylene terephthalate
>> film. The same material is available in block form under
>> another name or three, which unfortunately I do not remember.
>What is the mechanism of the leakage?
>Is it through the bulk of the material?
>Or is it over the surface?
>Possibly through adsorbed water?
Leakage of polyethylene terephthalate is usually not an issue, AFAIK,
and it does not adsorb water, I think. Pinholes and bulk breakdown are
issues. Surface leakage is not counted against the insulator's merit
Nylon is the one where water adsorption is a significant factor, but not
for all grades. IIRC, 11-11 does not adsorb water.
I gave my out-of-print plastics reference book to a moulding designer in
Hong Kong about 30 years ago. We got better mouldings as a result, but I
still wish I had the book.
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
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