<div dir="ltr"><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small;color:#000000">Paul,</div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small;color:#000000">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.</div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small;color:#000000"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small;color:#000000">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.<br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small;color:#000000"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small;color:#000000">--John</div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small;color:#000000"><br clear="all"></div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><font size="2"><span style="font-family:tahoma,sans-serif">John E. Simmons<br>Writer and Museum Consultant</span></font></div><div dir="ltr"><font size="2"><span style="font-family:tahoma,sans-serif">Museologica<br><i>and</i><br>Associate Curator of Collections<br>Earth and Mineral Science Museum & Art Gallery<br>Penn State University<br><i>and</i><br>Investigador Asociado, Departamento de Ornitologia<br>Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima</span></font><br></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Jan 13, 2023 at 1:09 PM Callomon,Paul <<a href="mailto:prc44@drexel.edu">prc44@drexel.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="msg4734722041015523225">
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<p class="MsoNormal">Folks,<u></u><u></u></p>
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<p class="MsoNormal">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.
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<p class="MsoNormal">If you know of any relevant literature, particularly published tests or long-term surveys on polystyrene, please pass the references on.
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<p class="MsoNormal" style="background:white"><span style="font-size:12pt;color:black">Paul Callomon<u></u><u></u></span></p>
<p class="MsoNormal" style="background:white"><span style="font-size:12pt;color:black">Collection Manager, Malacology and General Invertebrates<i><u></u><u></u></i></span></p>
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<p class="MsoNormal" style="background:white"><b><span style="font-size:12pt;color:black">Academy of Natural Sciences of Drexel University</span></b><b><span style="font-size:12pt;color:black"><u></u><u></u></span></b></p>
<p class="MsoNormal" style="background:white"><span style="font-size:12pt;color:black">1900 Benjamin Franklin Parkway, Philadelphia PA 19103-1195, USA<br>
<i><a href="mailto:prc44@drexel.edu" target="_blank"><span style="color:rgb(5,99,193)">prc44@drexel.edu</span></a> Tel 215-405-5096 - Fax 215-299-1170</i><u></u><u></u></span></p>
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