Cellulose acetate (CA) 1

Spectroscopy chart CA

Toothbrush, c. 1950

Cellulose acetate

Source

Hertford Museum.

History

Unused. Property of Robert Addis before entering the collection of Hertford Museum in 2002.

Material

The handle is made of the featured material cellulose acetate (unfilled, compare with the fish knife). The bristles are made of polyamide.

Degradation

Very good condition: there are a few minor scratches at the handle end of the toothbrush which may be manufacturing marks or the start of degradation. The museum number painted over a base coat may also be a source of potential trouble.

 

Degradation typical of the material not visible in this example

Degrading cellulose acetate can go crystalline although not to the extent of cellulose nitrate. Surface weeping can also occur. It can also give off a smell of vinegar/acetic acid.

Treatments

There is no safe way of removing the number. Tie on labels should be used rather than marking the object itself.

Display and storage

It should be kept in cool (ideally 2 - 5°C) and dry (ideally 20-30% RH) conditions. In storage it should be loosely wrapped in conservation grade acid free tissue and checked ideally every six months: look especially for changes to the texture of or shredding of the tissue. If you can smell vinegar then the object should be stored away from metal objects as acetic acid causes corrosion.

Cellulose acetate 2 >