Polystyrene (PS)

Spectroscopy chart PS

Cake stand, 1930s

Polystyrene

Source

MoDiP.

History

Purchased in a market and therefore likely to have had a life of use.

Material

Polystyrene base and tier, attached with a metal screw.

Degradation

Polystyrene is a chemically stable but brittle material. This object has evidence of stress marks caused as a result of the moulding process which will have been exacerbated by the drilling of the hole through which to pass the screw to hold its two parts together. The corrosion of the metal caused by contact with the air, not the polystyrene, may also have contributed to the stress cracking.

There is some residue from a sticky label.

 

Degradation typical of the material not visible in this example

None.

Treatments

The stress cracking cannot be reversed.

It may be possible to remove the residue from the sticky label with a swab just dampened with de-ionised water however the residue is close to a crack and it may be better to leave it alone. The corroding screw should be treated by a conservator to ensure it does not further damage the plastic.

Display and storage

Follow standard practice: keep in a stable environment and, when not on display, in the dark.

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