Re[2]: Suitable capacitor dialectrics

[Aric_C_Rothman-at-email.whirlpool-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

I made a stack cap with styrene sheet, and observed no degradation after 1
year 
immersion in a house blend of Diala-AX and Univolt (I ran out :).

Aric

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Subject: Re: Suitable capacitor dialectrics
Author:  "Tesla list" <tesla-at-pupman-dot-com> at INTERNET
Date:    8/15/00 8:25 AM


Original poster: "Bert Hickman" <bert.hickman-at-aquila-dot-com> 
     
Tesla list wrote:
> 
> Original poster: "Metlicka Marc" <mystuffs-at-orwell-dot-net> 
> 
> hello bert,
> i was wondering what exactly happens to polystyrene in oil? i've had the 
> cup cap soaking for some time now and checked it after your post, it
> doesn't seem mushy or anything?
> marc
     
Marc,
     
Well, my notes indicated that (supposedly!) polystyrene either degraded 
or dissolved in mineral oil, and that it had poor chemical resistance. 
Unfortunately, my notes do not indicate the original source of the 
information, - I suspect it may have come out of one of the many books 
on plastics I rented from the local library a couple of years back. 
     
However, after seeing your post, I did a bit more digging and found that 
other (web-based) polymers references seem to indicate that polystyrene 
suffers no damage after 30 days immersion and that it has excellent 
resistance/no attack by mineral oils (as long as they have no aromatic 
or alaphatic solvent content). However, polystyrene is significantly 
more brittle than polyethylene or polypropylene, and may be more prone 
to cracking under applied stress. 
     
Your mileage may vary, but if your cup caps seem to be working OK, go 
for it! :^)
     
-- Bert --
-- 
Bert Hickman
Stoneridge Engineering
Email:    bert.hickman-at-aquila-dot-com
Web Site: http://www.teslamania-dot-com