Cellulose nitrate (CN) 2

Spectroscopy chart CN

Pearlised hairbrush, c. 1930s

CN

Source

Donated by Steve Akhurst at the project's inaugural seminar.

History

The hair brush was probably used. After degradation began it was kept in a plastic bag.

Material

Both the brown and the pearlised areas of the brush handle and head are made of cellulose nitrate.

Degradation

Cellulose nitrate is a chemically unstable material. This example is discoloured, weeping acidic droplets, and going crystalline. It feels sticky. Its storage in a plastic bag, from which the acid could not escape, has accelerated the deterioration process.

 

Degradation typical of the material not visible in this example

It could smell of camphor.

Treatments

It is difficult to give advice for treatment of cellulose nitrate as any contact can lead to further deterioration. The acidic droplets could be removed with blotting paper or a lint free cloth by lightly patting the surface but both methods could lead to the surface of the material sticking to the surface of the object. They can also be removed with an almost dry swab barely dampened with deionised water and immediately dried however contact with water can lead to accelerated deterioration.

Display and storage

Ideally cellulose nitrate objects are kept in cooler (2 - 5°C) and dryer (20% - 30 % RH) conditions than other types of plastics to help slow down the degradation process. This object should be stored in a well-ventilated area and covered loosely with conservation grade acid free tissue paper or in a ventilated archival box. Ideally charcoal cloth would be placed inside the packaging of all cellulose nitrate objects to absorb volatile off gassing however it is expensive and needs to be changed regularly. For that reason you may decide to use it only for particularly degraded objects. It should be kept separate from other objects, especially those containing metal, to prevent any off-gassing affecting them. It should be checked every six months.

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