Permanence
of Plasticizers in
Polyvinylchloride (PVC)
Objects in the Museum Environment
Abstract from
the national meeting of the American Chemical Society 24aug00
Yvonne Shashoua, Department of Conservation, National Museum of
Denmark
Postbox 260 Brede, 2800 Lyngby, Denmark, Fax: +45 -33 47 33 27, yvonne.shashoua@natmus.dk
Plasticizers are the major additive in PVC
formulations, in percentage by weight and their influence
on the final plastics product. Examples of PVC in museums
include protective clothing, footwear, toys and medical
equipment. Since the 1930s, the most frequently used
plasticizer has been dioctyl phthalate. Much of the
literature assumes that any amount of phthalate is fully
compatible with the finished product. This is not the
experience within museums. Instability of plasticized PVC
is exhibited as migration from the bulk to the surface
layer, detected by a tacky feel to the plastic, formation
of oily droplets and adhesion to packaging materials.
This paper discusses the mechanisms by which loss of
phthalates from PVC objects occurs in a museum
environment. Findings from FTIR, SEM and surface wetting
examinations applied to both model and naturally degraded
objects are presented. The results suggest that
permanence of plasticizer is dependent on the amount
included during manufacture.
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