[NHCOLL-L:2281] RE: "paper or plastic"

[Simmons, John E]

I agree that cardboard can help buffer relative humidity, but this buffering action can also lead to worse damage that the RH might cause, particularly if it is acidic cardboard.  Acid migration will occur faster under conditions of high RH.  If the cardboard absorbs sufficient RH, this accelerated acidi migration will continue even after the RH cycle goes down.  While in some instances your are quite correct about the advantage given by the buffering of cardboard, if such humidity swings are a problem, you are better off coping with them by dehumidification or the use of a buffer that is not a container, such as silica gel in the cases.  The reason I recommended polystyrene boxes rather than the PET boxes is that the PS boxes seal better against the outside environment (including RH) than do the PET boxes.  The PET boxes are excellent in many ways, but they don't close very well.
 
--John

	-----Original Message----- 
	From: Paul Callomon [mailto:callomon at acnatsci.org] 
	Sent: Fri 5/7/2004 10:39 AM 
	To: Simmons, John E; nhcoll-l at lists.yale.edu; gregory.watkins-colwell at yale.edu 
	Cc: 
	Subject: [NHCOLL-L:2279] RE: "paper or plastic"
	
	

	Re: cardboard in collections
	
	Despite its being a cellulose product, the humidity-absorbing property of cardboard can be a real advantage in high-humidity environments. The same goes for wood, which in almost every other respect is not a good storage medium. As always, one should take a holistic view. If the building has proper humidity control and does not suffer from wild temperature swings, then impermeable slow-cooling plastic is a better medium than anything cellulose-based. If, however, there is a lot of humidity present at times then the ameliorating effects of cardboard may be a net benefit. Remember too that slow-cooling, slow-heating materials like sheet metal are magnets for condensation.
	
	Regards,
	
	PC.
	
	Paul Callomon
	Collections Manager
	Malacology, Invertebrate Paleontology and General Invertebrates
	Department of Malacology
	Academy of Natural Sciences
	1900 Parkway, Philadelphia PA 19103-1195, USA
	Tel 215-405-5096
	Fax 215-299-1170
	Secretary, American Malacological Society
	On the web at http://erato.acnatsci.org/ams/
	
	
	>>> "Simmons, John E" <jsimmons at ku.edu> 05/07/04 09:13AM >>>
	Depends on the paper or the plastic.  The only acceptable cardboard is acid-free board.  The drawbacks to cardboard include that it absorbs relative humidity, can attract pests, and you have to open the container to see the specimen (which means more handling and it will take you longer to do pest inspections).  I personally prefer rigid polystyrene boxes because you can see through them and they are very durable.  However, do not use polystyrene if you are using naphthelene or paradichlorobenzene (PDB) as fumigants, or anything else that contains benzene rings, because it will craze and melt the plastic.
	
	--John
	
	        -----Original Message-----
	        From: Gregory Watkins-Colwell [mailto:gregory.watkins-colwell at yale.edu]
	        Sent: Fri 5/7/2004 7:12 AM
	        To: nhcoll-l at lists.yale.edu
	        Cc:
	        Subject: [NHCOLL-L:2276] "paper or plastic"
	       
	       
	        Skeleton storage boxes:  plastic or cardboard?  I'd be interested in hearing the various opinions on this.  I have my opinion... but what do others think?
	       
	        greg
	       
	       
	
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