[NHCOLL-L:1354] Re: Large glass bottles

[Simmons, John E]

Amy,
Polycarbonate (PC) is a rigid (thermoset) plastic, and is more inclined to
crack than HDPE.  Like HDPE, it does not tolerate exposure to UV very well.
PC will yellow and become brittle with light exposure.  PC is also
susceptible to damage from compounds containing benzene rings, a serious
problem if you are fumigating with naphthalene or paradichlorobenzene, etc.
On the plus side, PC is very durable, and has high impact resistance.
However, it also scratches easily, is very susceptible to environmental
stress (RH and temperature fluctuations, contaminants, etc.), and has poor
fatigue and wear characteristics.  Its alcohol resistant rating is the same
as HDPE ("good"), it is almost as acid resistant as HDPE, but PC is only
rated poor for alkali exposure (HDPE ranks "good").
 
I looked at the containers on the web site.  Their weak spot is going to be
the lids, which are described as either "polyethylene" or "Camwear."  I
could not figure out what the latter material is.  The polyethylene I
suspect is not HDPE but PE because of the flexibility needed for a snap-top
lid (are the lids marked with any codes?).   A good seal is very important
to the long-term stability of fluid preserved specimens.  Oxidation is a
major cause of specimen (and probably preservative) deterioration.
 
However, the ultimate test is, of course, how well they do for you.  How
long have you had the containers in use?  Any idea how they compare to other
large containers for evaporative loss, etc?  Any problems with the
containers or the lids cracking?  Do you know of anyone else using them?
 
Thanks for the information on the containers.  Yours is the first
application of polycarbonate pails for fluid preserved specimens that I have
heard of.  Keep a record of their performance and environmental storage
conditions--it will be information of interest to all of us.
 
--John

-----Original Message-----
From: Amy Estep [mailto:aestep at ou.edu]
Sent: Friday, November 30, 2001 8:54 AM
To: jsimmons at KU.EDU
Cc: hendler at nhm.org; nhcoll-l at lists.yale.edu
Subject: Re: [NHCOLL-L:1349] Re: Large glass bottles


John, 

I cannot find a composition code on the pails.  Here is one description of
the material from Cambro's web site (for more detail, see link below): 


Camwear® Polycarbonate 


            Virtually unbreakable. 
            Storage containers are clear for easy identifying and
inventorying. 
            Non-porous, smooth surface resists staining. 
            Temperature range: ?40°F to +210°F (?40°C to +99°C). 
            Food Pans also available in Camwear White (148) and Black (110) 


If you follow this link to their web
<http://us.cambro.com/webapp/commerce/command/ExecMacro/CAMBRO/macros/main2.
d2w/report?cgname=Storage%20%26%20Shelving> site, you can scroll down and
see the pail we have.  It is item number RFSCW22, the 22 Qt. Camwear Round
Pail. 


Any experience with polycarbonate? 


Thanks, 
Amy 
  


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