Jelly sandals, 1990s
Source
MoDiP.
History
Acquired new.
Material
Entirely made of the featured material, polyvinyl chloride, except for the metal buckle.
Degradation
Polyvinyl chloride is a chemically unstable material. It was first noticed that these shoes were going sticky on 3.4.2014. This is caused by the migration of the plasticiser (ethyleneglycolmonoricanoleate) which is deposited as a liquid in places. The sole is apparently still flexible but the straps are beginning to stiffen. The metal is not corroded. The green is possibily going yellow.
Degradation typical of the material not visible in this example
PVC loses flexibility as the plasticiser migrates. Degrading PVC emits acidic vapours which will corrode metal as well as encourage the onset of deterioration in other PVC objects.
Treatments
The damage cannot be reversed. The object should be monitored on a six monthly basis to check for colour change and any other deterioration.
Display and storage
The shoes should be displayed and stored supported as if on a foot with silicone release paper ensuring the support does not stick to the object. Make sure the support maintains the shape without putting any pressure on the material. In store they should be loosely wrapped in silicone release paper. Follow standard practice: keep in a stable environment and, when not on display,in the dark.