As the art conservation field grows and gains more of a scientific footing, our understanding and concern increases for artifacts that date from the last 100 years. Many of these items contain modern materials (i.e.man-made paints and plastics, semi-synthetic and synthetic textile fibers, digital media.) Modern materials can deteriorate rapidly due to their manufacturing and proximity to/mixture with other materials. The inherent vices in these materials can be exacerbated by inappropriate storage and display conditions.
Two new MTS Handouts written by MTS Conservator Kayla Silvia are now available to download and distribute:
Modern materials can be identified using non-destructive and destructive means. The simplest non-destructive techniques are to use the appearance and odor of the artifact and its parts to identify its composition. Examine the material’s look, feel, surface, weight, pattern, style, sound when gently tapped, and smell when rubbed. However, odor given off by modern materials can be subjective (see Assessing Modern Materials handout). FTIR is a non-destructive analytical technique that has been commonly used to identify the polymers in modern materials. Other analytical techniques that can be used are GC-MS, XRF, SEM-EDX, and FT-Raman.
Learning to characterize changes to modern materials allows us to catch the early warning signs that indicate material is deteriorating. These include:
Blistering
Small surface bubbles where there is physical or chemical distortion
Bloom
Growths on the surface as a result of additives migrating to the surface of the plastic
Crazing
Pattern (regular or irregular) of microscopic cracks either at the surface of the plastic or internally
De-lamination
Peeling apart of multi-layer plastics due to incompatibility as the layers degrade
Discoloration
Change in color produced by degrading plastics caused by UV light and environment
Warping
Distortions, often accompanied by weeping, that can result in cracking
Weeping
Surface liquid caused by migrating plasticizer or acidic degradation products
1930s sheer dress composed of synthetic fibers. Courtesy Main State Museum.
The chart below will help in the identification and assessment of modern materials.
Untitled work of art made from urethane foam by John Chamberlain c 1970. Currently on exhibit in “Objects to Be Destroyed” at the Akron Art Museum through August 9, 2020. Copyright Akron Art Museum.
Some of the degradation products produced by modern materials can be harmful or an irritant. Therefore, please follow safety guidelines to protect yourself and others:
- Wear gloves (nitrile)
- Wash hands after handling
(even if wearing gloves) - Sniff odors cautiously (especially
if artifact has been stored wrapped, boxed, or in a bag) - Do not taste residues from an artifact to determine if they are acidic
Due to the risks to museum collections from modern materials used in fabrics and clothing accessories, you should consider storing them separately from other textile materials when possible.
- Some plastics are sensitive to water (i.e. polyurethane foam, polyester) so storing in conditions with low relative humidity (RH) of 30% is recommended. Low RH is best for a wide range of modern materials; however, casein should be stored in a higher RH (50-60%).
- Storage of plastics at low temperatures can slow down the rate of deterioration, however this can be potentially hazardous for composite materials. Care should be taken to make sure water does not condensate on the plastics.
- The degradation of modern materials can be slowed by placing absorbents (i.e. activated carbon, silica gel, zeolites) in their storage container.
- If a textile or costume accessory is sticky, it can be stored wrapped in silicone-release paper or Tyvek®.