Cellulose nitrate

Paul Storch <paul.storch [at] mnhs__org> writes

>Has anyone ever found white, acicular crystals growing on the
>surface of a cellulose nitrate object?  We recently removed a chair
>upholstered in faux-leather from exhibit after 12 years and found
>the sides and part of the back fairly uniformly covered with the
>crystals. The crystals brush off easily and there is no visible
>damage to the surface.  I tested the coating of the upholstery and
>found it to be cellulose nitrate, which is common in faux-leathers.
>The chair was made in the 1950's.  There was no camphor smell, or
other odors, and none of the other objects in the case with the
chair underwent any changes, so we have ruled out VOC's from the
case materials. The crystals were soluble in water, ethanol and
acetone.

This is hard to tell without analysis.  If camphor can
definitely be ruled out, chemical plasticizers or other additives
are the next culprits to suspect.  My survey of the Brantham
Company, UK manufacturing records showed that many additives in the
form of colorants, oils and stabilizers were tried in order to
improve the properties.

Sorry, not much of an answer, but I think you might have to wait for
the analysis.

Linda S. Roundhill
Art and Antiquities Conservation
18121 157th Ave NE
Woodinville, WA 98072
425-481-0720


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                  Conservation DistList Instance 18:23
                 Distributed: Monday, November 22, 2004
                       Message Id: cdl-18-23-002
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