Newsgroup sci.polymers 10814

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I'm currently facing a problem that many manufacturers / distributors of
janitorial products face: What material should you use for detergents?
Traditionally HDPE bottles have been used for detergents and that's
about the extent of my knowledge when it comes to plastics. Recently an
oppotunity has arisen whereby we can buy 500-ml/1 litre and 5 litre PET
"Jerry cans" at an extremely competitive price compared to the
equivalent HDPE containers of the same size.As far as I can make out PET
is widely used for drinking water bottles.
Stress cracking was a problem for poorly made HDPE containers, will it
be for PET containers? Our most popular container is a 130 gram
(anything less and they would "crack") 5 litre Jerry can manufactured
from HDPE, what do I need to look out for when I'm looking at PET
containers?
We fill the containers with three different grades of dishwashing
liquid, laundry liquid, fabric softener, disinfectants, sanitisers and
bleach (5-6% Sodium Hypochlorite). Can anybody forsee any problems with
using PET?
I would be grateful if any of the subscribers to this newsgroup were
able to shed some light on a subject which I've found to be closely
guarded by plastic bottle manufacturers, so much so that I wonder if
they can answer the question?
Bruce Cole
Marketing Manager (Detergents Division)

Of course, Mr. Glazman is correct- I meant poly(acetylene) (which is not
easy to make- one of the best methods, which is indirect, like the
dehydrohalogenation of poly(vinyl chloride) is to polymerize a bulky
structure which is leaves later and provides the fouble bond-see Brott's
papers in Polymer ca. late 1980's)
PBut is an insulator and a damn good rubber. (which it wouldn't be if
conjugated-this imparts stiffness to the chain!)
The point is that, yes there are conjugated polymers, and people don't
understand them well, so the more in on the theorizing, the better.
Brent
Jerry Glazman wrote:
> 
> Brent Viers wrote:
> >
> > All of the conducting polymers have conjugated backbones-that's why they
> > conduct electricity so well. Also poly(butadiene) when made correctly
> > (without dangling chain defects) will be completely conjugated-even
> > poorly synthesized PBut has long conjugated sequences.
> >
> > Brent D. Viers
> > Department of Chemistry
> > Polymer Research Center
> > Mail Location 0172
> > University of Cincinnati
> > Cincinnati, OH 45221-0172
> > Telephones: 513-556-9291
> >             513-556-9290
> > Fax: 513-556-9239
> > e-mail:viersbd@ucbeh.san.uc.edu
> >        brent@jemcom.crs.uc.edu
> > http://www.jem.research.uc.edu/~brent
> 
> I don't believe that is correct.
> 
> Butadiene's structure is CH2=CH-CH=CH2
> 
> When it undergoes polymerization the resulting chain repeat unit
> (assuming no dangling side chains) is:
> 
>         -[CH2-CH=CH-CH2]-
> 
> Therefore it is not a conjugated structure since a conjugated structure
> has alternating single and double bonds.  In polybutadiene the
> alternating structure is
> 
>  -single-double-single-single-double-single-single-double-single-etc.
> 
> With two single bonds on each side of the double bond there is not the
> opportunity for the delocalization of the electrons that you get with a
> true conjugated system.  I don't believe that polybutadiene is
> conductive.
> 
> Jerry Glazman
> Non-Metallic Materials Services, Inc.
> jerryg@esslink.com
-- 
Brent D. Viers                 
Department of Chemistry         
Polymer Research Center         
Mail Location 0172              
University of Cincinnati        
Cincinnati, OH 45221-0172       
Telephones: 513-556-9291        
            513-556-9290        
Fax: 513-556-9239                
e-mail:viersbd@ucbeh.san.uc.edu 
       brent@jemcom.crs.uc.edu
http://www.jem.research.uc.edu/~brent

For those who asked, I found the company that does DEVULCANIZATION of
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Check out http://www.americantire.com

Hello,
I am looking for some reference listing density of PET at different 
temperatures (from room temperature to its melting point) - also the
initial crystallinity of the polymer for which this density is reported.
I've already looked through common handbooks, chemical abstracts, etc.
It's easy to find PET density at room temperature but not as a function of
temperature.
Any help would be greatly appreciated. please reply by email.
Thanks.
Sincerely
Vishal Bansal
vbansal@mailhost.ecn.uoknor.edu
Chemical Engineering and Material Sciences
University of Oklahoma
Norman, OK 73019.

Hi Cathal,
I recall that DOA does carry a USFDA sanction for use in plasticised PVC 
compounds for food contact-- I think in meat and produce film wrap as 
well as plastisol foamed gaskets for jar cap liners.  I recall the C.F.R. (code 
of federal regulations) reference as CFR-21.2154 or 2155??
However two good references should answer the question:
1)- "Encyclopedia of PVC", edited by L.I.Nass, published by Marcel Dekker, 
NYC.
2)- "Plasticisers", by Joe Darby and Kern Sears, don't know the publisher.
A major DOA supplier in the U.S. is Aristech Chemicals, Pittsburgh PA. Ask 
for Dick Koslowski.
Hope this helps, Cathal.
Regards, Skip