Re: Polythene porosity ?

Paul Nutteing wrote:
>
> "Uncle Al" <UncleAl0@xxxxxxxxxxxxx> wrote in message
> news:4391C512.B12B5A3A@xxxxxxxxxxxxxxxx
> > Paul Nutteing wrote:
> > >
> > > For biological material in a sealed polythene bag
> > > but in surface contact with the polythene, is there any
> > > possibility of any
> > > cellular material migrating, in picogram terms,
> > > through the polythene ***.?
> >
> > Non-polar materials may diffuse into polyethylene, such as lipids and
> > fatty acids. Picograms? *Everything* molecular will penetrate nearly
> > anything at picogram levels. Water diffuses through polyolefins at
> > picogram levels.
> >
> > --
> > Uncle Al
> > http://www.mazepath.com/uncleal/
> > (Toxic URL! Unsafe for children and most mammals)
> > http://www.mazepath.com/uncleal/qz.pdf
>
> But could the smallest nucleated cellular material in an oil or water medium
> migrate across polythene *** of order 40 to 80 mirons thickness?

80 microns is 3 mils. That's very thin if you want guaranteed
containment. Worry about film microscopic physical flaws leaking and
overt material failure from contact with oil.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf
.