[Nhcoll-l] Clear styrene in collections

[John E Simmons]

Paul,
Polystyrene will yellow or turn translucent, craze, and warp (because it
softens) in the presence of benzene rings, so if the boxes are exposed to
naphthalene, PDB, or any number of cleaning products that is likely to
happen. From your description it sounds like the boxes from private
collections were exposed to benzene rings.

The only drawback I have heard mentioned with clear, rigid polystyrene is
that when the surface is scratched it can offgas unwanted byproducts, but I
do not have a reference for this and have not personally seen any damage
from it. Perhaps one of the conservators on the list can offer better
information.

--John

John E. Simmons
Writer and Museum Consultant
Museologica
*and*
Associate Curator of Collections
Earth and Mineral Science Museum & Art Gallery
Penn State University
*and*
Investigador Asociado, Departamento de Ornitologia
Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima


On Fri, Jan 13, 2023 at 1:09 PM Callomon,Paul <prc44 at drexel.edu> wrote:

> Folks,
>
>
>
> We are working on a new storage system for small dry specimens that is
> more space-efficient than our current tray-and-vial setup. As part of the
> research, I’m trying to assess the long-term durability of polystyrene –
> the material from which clear plastic boxes (such as those sold by Althor)
> is made. We have been using this since the 1980s and with very few
> exceptions it has remained stable. However, we have also acquired private
> collections with polystyrene boxes that have yellowed and crazed over
> similar time periods. Inquiries in the industry previously revealed that
> the formula for polystyrene can vary between production runs, as the
> proportion of flow agent (an additive that helps the liquid plastic flow
> and form itself to the mold) to plastic can be adjusted to compensate for
> temperature and other environmental factors.
>
>
>
> If you know of any relevant literature, particularly published tests or
> long-term surveys on polystyrene, please pass the references on.
>
>
>
> Paul Callomon
>
> Collection Manager, Malacology and General Invertebrates
> ------------------------------
>
> *Academy of Natural Sciences of Drexel University*
>
> 1900 Benjamin Franklin Parkway, Philadelphia PA 19103-1195, USA
> *prc44 at drexel.edu <prc44 at drexel.edu> Tel 215-405-5096 - Fax 215-299-1170*
>
>
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